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FFMPEG-CODECS(1)					      FFMPEG-CODECS(1)

NAME
       ffmpeg-codecs - FFmpeg codecs

DESCRIPTION
       This document describes the codecs (decoders and	encoders) provided by
       the libavcodec library.

CODEC OPTIONS
       libavcodec provides some	generic	global options,	which can be set on
       all the encoders	and decoders. In addition each codec may support so-
       called private options, which are specific for a	given codec.

       Sometimes, a global option may only affect a specific kind of codec,
       and may be nonsensical or ignored by another, so	you need to be aware
       of the meaning of the specified options.	Also some options are meant
       only for	decoding or encoding.

       Options may be set by specifying	-option	value in the FFmpeg tools, or
       by setting the value explicitly in the "AVCodecContext" options or
       using the libavutil/opt.h API for programmatic use.

       The list	of supported options follow:

       b integer (encoding,audio,video)
	   Set bitrate in bits/s. Default value	is 200K.

       ab integer (encoding,audio)
	   Set audio bitrate (in bits/s). Default value	is 128K.

       bt integer (encoding,video)
	   Set	video  bitrate	tolerance (in bits/s). In 1-pass mode, bitrate
	   tolerance specifies how far ratecontrol is willing to deviate  from
	   the	target	average	 bitrate value.	This is	not related to min/max
	   bitrate. Lowering tolerance too  much  has  an  adverse  effect  on
	   quality.

       flags flags (decoding/encoding,audio,video,subtitles)
	   Set generic flags.

	   Possible values:

	   mv4 Use four	motion vector by macroblock (mpeg4).

	   qpel
	       Use 1/4 pel motion compensation.

	   loop
	       Use loop	filter.

	   qscale
	       Use fixed qscale.

	   pass1
	       Use internal 2pass ratecontrol in first pass mode.

	   pass2
	       Use internal 2pass ratecontrol in second	pass mode.

	   gray
	       Only decode/encode grayscale.

	   psnr
	       Set error[?] variables during encoding.

	   truncated
	       Input bitstream might be	randomly truncated.

	   drop_changed
	       Don't  output frames whose parameters differ from first decoded
	       frame in	stream.	 Error AVERROR_INPUT_CHANGED is	returned  when
	       a frame is dropped.

	   ildct
	       Use interlaced DCT.

	   low_delay
	       Force low delay.

	   global_header
	       Place global headers in extradata instead of every keyframe.

	   bitexact
	       Only write platform-, build- and	time-independent data. (except
	       (I)DCT).	  This	ensures	 that  file  and  data	checksums  are
	       reproducible and	match between platforms. Its  primary  use  is
	       for regression testing.

	   aic Apply H263 advanced intra coding	/ mpeg4	ac prediction.

	   ilme
	       Apply interlaced	motion estimation.

	   cgop
	       Use closed gop.

	   output_corrupt
	       Output even potentially corrupted frames.

       time_base rational number
	   Set codec time base.

	   It  is  the fundamental unit	of time	(in seconds) in	terms of which
	   frame timestamps are	represented. For fixed-fps  content,  timebase
	   should  be  "1  /  frame_rate"  and	timestamp increments should be
	   identically 1.

       g integer (encoding,video)
	   Set the group of picture (GOP) size.	Default	value is 12.

       ar integer (decoding/encoding,audio)
	   Set audio sampling rate (in Hz).

       ac integer (decoding/encoding,audio)
	   Set number of audio channels.

       cutoff integer (encoding,audio)
	   Set cutoff bandwidth. (Supported only  by  selected	encoders,  see
	   their respective documentation sections.)

       frame_size integer (encoding,audio)
	   Set audio frame size.

	   Each	  submitted   frame  except  the  last	must  contain  exactly
	   frame_size samples per  channel.  May  be  0	 when  the  codec  has
	   CODEC_CAP_VARIABLE_FRAME_SIZE  set,	in that	case the frame size is
	   not restricted. It is set by	some  decoders	to  indicate  constant
	   frame size.

       frame_number integer
	   Set the frame number.

       delay integer
       qcomp float (encoding,video)
	   Set	video  quantizer  scale	 compression  (VBR).  It  is used as a
	   constant in the ratecontrol equation. Recommended range for default
	   rc_eq: 0.0-1.0.

       qblur float (encoding,video)
	   Set video quantizer scale blur (VBR).

       qmin integer (encoding,video)
	   Set min video quantizer scale (VBR).	Must be	 included  between  -1
	   and 69, default value is 2.

       qmax integer (encoding,video)
	   Set	max  video  quantizer scale (VBR). Must	be included between -1
	   and 1024, default value is 31.

       qdiff integer (encoding,video)
	   Set max difference between the quantizer scale (VBR).

       bf integer (encoding,video)
	   Set max number of B frames between non-B-frames.

	   Must	be an integer between -1 and 16. 0  means  that	 B-frames  are
	   disabled.  If  a  value  of -1 is used, it will choose an automatic
	   value depending on the encoder.

	   Default value is 0.

       b_qfactor float (encoding,video)
	   Set qp factor between P and B frames.

       codec_tag integer
       bug flags (decoding,video)
	   Workaround not auto detected	encoder	bugs.

	   Possible values:

	   autodetect
	   xvid_ilace
	       Xvid interlacing	bug (autodetected if fourcc==XVIX)

	   ump4
	       (autodetected if	fourcc==UMP4)

	   no_padding
	       padding bug (autodetected)

	   amv
	   qpel_chroma
	   std_qpel
	       old standard qpel (autodetected per fourcc/version)

	   qpel_chroma2
	   direct_blocksize
	       direct-qpel-blocksize bug (autodetected per fourcc/version)

	   edge
	       edge padding bug	(autodetected per fourcc/version)

	   hpel_chroma
	   dc_clip
	   ms  Workaround various bugs in microsoft broken decoders.

	   trunc
	       trancated frames

       strict integer (decoding/encoding,audio,video)
	   Specify how strictly	to follow the standards.

	   Possible values:

	   very
	       strictly	conform	to an older more strict	version	of the spec or
	       reference software

	   strict
	       strictly	conform	to all the things in the spec no  matter  what
	       consequences

	   normal
	   unofficial
	       allow unofficial	extensions

	   experimental
	       allow   non   standardized  experimental	 things,  experimental
	       (unfinished/work	in  progress/not  well	tested)	 decoders  and
	       encoders.   Note:  experimental	decoders  can  pose a security
	       risk, do	not use	this for decoding untrusted input.

       b_qoffset float (encoding,video)
	   Set QP offset between P and B frames.

       err_detect flags	(decoding,audio,video)
	   Set error detection flags.

	   Possible values:

	   crccheck
	       verify embedded CRCs

	   bitstream
	       detect bitstream	specification deviations

	   buffer
	       detect improper bitstream length

	   explode
	       abort decoding on minor error detection

	   ignore_err
	       ignore decoding errors, and continue decoding.  This is	useful
	       if  you	want  to  analyze the content of a video and thus want
	       everything to be	decoded	no matter what.	This option  will  not
	       result in a video that is pleasing to watch in case of errors.

	   careful
	       consider	things that violate the	spec and have not been seen in
	       the wild	as errors

	   compliant
	       consider	all spec non compliancies as errors

	   aggressive
	       consider	things that a sane encoder should not do as an error

       has_b_frames integer
       block_align integer
       rc_override_count integer
       maxrate integer (encoding,audio,video)
	   Set max bitrate tolerance (in bits/s). Requires bufsize to be set.

       minrate integer (encoding,audio,video)
	   Set	min bitrate tolerance (in bits/s). Most	useful in setting up a
	   CBR encode. It is of	little use elsewise.

       bufsize integer (encoding,audio,video)
	   Set ratecontrol buffer size (in bits).

       i_qfactor float (encoding,video)
	   Set QP factor between P and I frames.

       i_qoffset float (encoding,video)
	   Set QP offset between P and I frames.

       dct integer (encoding,video)
	   Set DCT algorithm.

	   Possible values:

	   auto
	       autoselect a good one (default)

	   fastint
	       fast integer

	   int accurate	integer

	   mmx
	   altivec
	   faan
	       floating	point AAN DCT

       lumi_mask float (encoding,video)
	   Compress bright areas stronger than medium ones.

       tcplx_mask float	(encoding,video)
	   Set temporal	complexity masking.

       scplx_mask float	(encoding,video)
	   Set spatial complexity masking.

       p_mask float (encoding,video)
	   Set inter masking.

       dark_mask float (encoding,video)
	   Compress dark areas stronger	than medium ones.

       idct integer (decoding/encoding,video)
	   Select IDCT implementation.

	   Possible values:

	   auto
	   int
	   simple
	   simplemmx
	   simpleauto
	       Automatically pick a IDCT compatible with the simple one

	   arm
	   altivec
	   sh4
	   simplearm
	   simplearmv5te
	   simplearmv6
	   simpleneon
	   xvid
	   faani
	       floating	point AAN IDCT

       slice_count integer
       ec flags	(decoding,video)
	   Set error concealment strategy.

	   Possible values:

	   guess_mvs
	       iterative motion	vector (MV) search (slow)

	   deblock
	       use strong deblock filter for damaged MBs

	   favor_inter
	       favor predicting	from the previous frame	instead	of the current

       bits_per_coded_sample integer
       aspect rational number (encoding,video)
	   Set sample aspect ratio.

       sar rational number (encoding,video)
	   Set sample aspect ratio. Alias to aspect.

       debug flags (decoding/encoding,audio,video,subtitles)
	   Print specific debug	info.

	   Possible values:

	   pict
	       picture info

	   rc  rate control

	   bitstream
	   mb_type
	       macroblock (MB) type

	   qp  per-block quantization parameter	(QP)

	   dct_coeff
	   green_metadata
	       display complexity metadata for the upcoming frame, GoP or  for
	       a given duration.

	   skip
	   startcode
	   er  error recognition

	   mmco
	       memory management control operations (H.264)

	   bugs
	   buffers
	       picture buffer allocations

	   thread_ops
	       threading operations

	   nomc
	       skip motion compensation

       cmp integer (encoding,video)
	   Set full pel	me compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard	transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal,	slow

	   zero
	       0

	   vsad
	       sum of absolute vertical	differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving	sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       subcmp integer (encoding,video)
	   Set sub pel me compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard	transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal,	slow

	   zero
	       0

	   vsad
	       sum of absolute vertical	differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving	sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       mbcmp integer (encoding,video)
	   Set macroblock compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard	transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal,	slow

	   zero
	       0

	   vsad
	       sum of absolute vertical	differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving	sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       ildctcmp	integer	(encoding,video)
	   Set interlaced dct compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard	transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal,	slow

	   zero
	       0

	   vsad
	       sum of absolute vertical	differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving	sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       dia_size	integer	(encoding,video)
	   Set diamond type & size for motion estimation.

	   (1024, INT_MAX)
	       full motion estimation(slowest)

	   (768, 1024]
	       umh motion estimation

	   (512, 768]
	       hex motion estimation

	   (256, 512]
	       l2s diamond motion estimation

	   [2,256]
	       var diamond motion estimation

	   (-1,	 2)
	       small diamond motion estimation

	   -1  funny diamond motion estimation

	   (INT_MIN, -1)
	       sab diamond motion estimation

       last_pred integer (encoding,video)
	   Set amount of motion	predictors from	the previous frame.

       precmp integer (encoding,video)
	   Set pre motion estimation compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard	transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal,	slow

	   zero
	       0

	   vsad
	       sum of absolute vertical	differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving	sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       pre_dia_size integer (encoding,video)
	   Set diamond type & size for motion estimation pre-pass.

       subq integer (encoding,video)
	   Set sub pel motion estimation quality.

       me_range	integer	(encoding,video)
	   Set limit motion vectors range (1023	for DivX player).

       global_quality integer (encoding,audio,video)
       slice_flags integer
       mbd integer (encoding,video)
	   Set macroblock decision algorithm (high quality mode).

	   Possible values:

	   simple
	       use mbcmp (default)

	   bits
	       use fewest bits

	   rd  use best	rate distortion

       rc_init_occupancy integer (encoding,video)
	   Set number of bits which should be loaded into the rc buffer	before
	   decoding starts.

       flags2 flags (decoding/encoding,audio,video,subtitles)
	   Possible values:

	   fast
	       Allow non spec compliant	speedup	tricks.

	   noout
	       Skip bitstream encoding.

	   ignorecrop
	       Ignore cropping information from	sps.

	   local_header
	       Place global headers at every keyframe instead of in extradata.

	   chunks
	       Frame data might	be split into multiple chunks.

	   showall
	       Show all	frames before the first	keyframe.

	   export_mvs
	       Export	 motion	   vectors    into    frame   side-data	  (see
	       "AV_FRAME_DATA_MOTION_VECTORS") for codecs that support it. See
	       also doc/examples/export_mvs.c.

	   skip_manual
	       Do not skip samples and export skip information as  frame  side
	       data.

	   ass_ro_flush_noop
	       Do not reset ASS	ReadOrder field	on flush.

	   icc_profiles
	       Generate/parse embedded ICC profiles from/to colorimetry	tags.

       export_side_data	flags (decoding/encoding,audio,video,subtitles)
	   Possible values:

	   mvs Export	 motion	   vectors    into    frame   side-data	  (see
	       "AV_FRAME_DATA_MOTION_VECTORS") for codecs that support it. See
	       also doc/examples/export_mvs.c.

	   prft
	       Export encoder Producer Reference Time  into  packet  side-data
	       (see "AV_PKT_DATA_PRFT")	for codecs that	support	it.

	   venc_params
	       Export  video  encoding parameters through frame	side data (see
	       "AV_FRAME_DATA_VIDEO_ENC_PARAMS") for codecs that  support  it.
	       At present, those are H.264 and VP9.

	   film_grain
	       Export  film  grain  parameters	through	 frame	side data (see
	       "AV_FRAME_DATA_FILM_GRAIN_PARAMS").  Supported  at  present  by
	       AV1 decoders.

       threads integer (decoding/encoding,video)
	   Set	the  number  of	threads	to be used, in case the	selected codec
	   implementation supports multi-threading.

	   Possible values:

	   auto, 0
	       automatically select the	number of threads to set

	   Default value is auto.

       dc integer (encoding,video)
	   Set intra_dc_precision.

       nssew integer (encoding,video)
	   Set nsse weight.

       skip_top	integer	(decoding,video)
	   Set number of macroblock rows at the	top which are skipped.

       skip_bottom integer (decoding,video)
	   Set number of macroblock rows at the	bottom which are skipped.

       profile integer (encoding,audio,video)
	   Set encoder	codec  profile.	 Default  value	 is  unknown.  Encoder
	   specific   profiles	 are   documented   in	the  relevant  encoder
	   documentation.

       level integer (encoding,audio,video)
	   Set the encoder level. This level depends on	 the  specific	codec,
	   and	might correspond to the	profile	level. It is set by default to
	   unknown.

	   Possible values:

	   unknown
       lowres integer (decoding,audio,video)
	   Decode at 1=	1/2, 2=1/4, 3=1/8 resolutions.

       mblmin integer (encoding,video)
	   Set min macroblock lagrange factor (VBR).

       mblmax integer (encoding,video)
	   Set max macroblock lagrange factor (VBR).

       skip_loop_filter	integer	(decoding,video)
       skip_idct	integer	(decoding,video)
       skip_frame	integer	(decoding,video)
	   Make	 decoder  discard  processing  depending  on  the  frame  type
	   selected by the option value.

	   skip_loop_filter  skips frame loop filtering, skip_idct skips frame
	   IDCT/dequantization,	skip_frame skips decoding.

	   Possible values:

	   none
	       Discard no frame.

	   default
	       Discard useless frames like 0-sized frames.

	   noref
	       Discard all non-reference frames.

	   bidir
	       Discard all bidirectional frames.

	   nokey
	       Discard all frames excepts keyframes.

	   nointra
	       Discard all frames except I frames.

	   all Discard all frames.

	   Default value is default.

       bidir_refine integer (encoding,video)
	   Refine the two motion vectors used in bidirectional macroblocks.

       keyint_min integer (encoding,video)
	   Set minimum interval	between	IDR-frames.

       refs integer (encoding,video)
	   Set reference frames	to consider for	motion compensation.

       trellis integer (encoding,audio,video)
	   Set rate-distortion optimal quantization.

       mv0_threshold integer (encoding,video)
       compression_level integer (encoding,audio,video)
       bits_per_raw_sample integer
       channel_layout integer (decoding/encoding,audio)
	   Possible values:

       request_channel_layout integer (decoding,audio)
	   Possible values:

       rc_max_vbv_use float (encoding,video)
       rc_min_vbv_use float (encoding,video)
       color_primaries integer (decoding/encoding,video)
	   Possible values:

	   bt709
	       BT.709

	   bt470m
	       BT.470 M

	   bt470bg
	       BT.470 BG

	   smpte170m
	       SMPTE 170 M

	   smpte240m
	       SMPTE 240 M

	   film
	       Film

	   bt2020
	       BT.2020

	   smpte428
	   smpte428_1
	       SMPTE ST	428-1

	   smpte431
	       SMPTE 431-2

	   smpte432
	       SMPTE 432-1

	   jedec-p22
	       JEDEC P22

       color_trc integer (decoding/encoding,video)
	   Possible values:

	   bt709
	       BT.709

	   gamma22
	       BT.470 M

	   gamma28
	       BT.470 BG

	   smpte170m
	       SMPTE 170 M

	   smpte240m
	       SMPTE 240 M

	   linear
	       Linear

	   log
	   log100
	       Log

	   log_sqrt
	   log316
	       Log square root

	   iec61966_2_4
	   iec61966-2-4
	       IEC 61966-2-4

	   bt1361
	   bt1361e
	       BT.1361

	   iec61966_2_1
	   iec61966-2-1
	       IEC 61966-2-1

	   bt2020_10
	   bt2020_10bit
	       BT.2020 - 10 bit

	   bt2020_12
	   bt2020_12bit
	       BT.2020 - 12 bit

	   smpte2084
	       SMPTE ST	2084

	   smpte428
	   smpte428_1
	       SMPTE ST	428-1

	   arib-std-b67
	       ARIB STD-B67

       colorspace integer (decoding/encoding,video)
	   Possible values:

	   rgb RGB

	   bt709
	       BT.709

	   fcc FCC

	   bt470bg
	       BT.470 BG

	   smpte170m
	       SMPTE 170 M

	   smpte240m
	       SMPTE 240 M

	   ycocg
	       YCOCG

	   bt2020nc
	   bt2020_ncl
	       BT.2020 NCL

	   bt2020c
	   bt2020_cl
	       BT.2020 CL

	   smpte2085
	       SMPTE 2085

	   chroma-derived-nc
	       Chroma-derived NCL

	   chroma-derived-c
	       Chroma-derived CL

	   ictcp
	       ICtCp

       color_range integer (decoding/encoding,video)
	   If used as input parameter, it serves as a  hint  to	 the  decoder,
	   which color_range the input has.  Possible values:

	   tv
	   mpeg
	   limited
	       MPEG (219*2^(n-8))

	   pc
	   jpeg
	   full
	       JPEG (2^n-1)

       chroma_sample_location integer (decoding/encoding,video)
	   Possible values:

	   left
	   center
	   topleft
	   top
	   bottomleft
	   bottom
       log_level_offset	integer
	   Set the log level offset.

       slices integer (encoding,video)
	   Number of slices, used in parallelized encoding.

       thread_type flags (decoding/encoding,video)
	   Select which	multithreading methods to use.

	   Use	of frame will increase decoding	delay by one frame per thread,
	   so clients which cannot provide future frames should	not use	it.

	   Possible values:

	   slice
	       Decode more than	one part of a single frame at once.

	       Multithreading using slices  works  only	 when  the  video  was
	       encoded with slices.

	   frame
	       Decode more than	one frame at once.

	   Default value is slice+frame.

       audio_service_type integer (encoding,audio)
	   Set audio service type.

	   Possible values:

	   ma  Main Audio Service

	   ef  Effects

	   vi  Visually	Impaired

	   hi  Hearing Impaired

	   di  Dialogue

	   co  Commentary

	   em  Emergency

	   vo  Voice Over

	   ka  Karaoke

       request_sample_fmt sample_fmt (decoding,audio)
	   Set	sample	format	audio decoders should prefer. Default value is
	   "none".

       pkt_timebase rational number
       sub_charenc encoding (decoding,subtitles)
	   Set the input subtitles character encoding.

       field_order  field_order	(video)
	   Set/override	the field order	of the video.  Possible	values:

	   progressive
	       Progressive video

	   tt  Interlaced video, top field coded and displayed first

	   bb  Interlaced video, bottom	field coded and	displayed first

	   tb  Interlaced video, top coded first, bottom displayed first

	   bt  Interlaced video, bottom	coded first, top displayed first

       skip_alpha bool (decoding,video)
	   Set to 1 to disable processing  alpha  (transparency).  This	 works
	   like	 the  gray  flag  in  the  flags  option  which	 skips	chroma
	   information instead of alpha. Default is 0.

       codec_whitelist list (input)
	   "," separated list of allowed decoders. By default all are allowed.

       dump_separator string (input)
	   Separator used to separate the fields printed on the	 command  line
	   about  the  Stream parameters.  For example,	to separate the	fields
	   with	newlines and indentation:

		   ffprobe -dump_separator "
					     "	-i ~/videos/matrixbench_mpeg2.mpg

       max_pixels integer (decoding/encoding,video)
	   Maximum number of pixels per	image. This value can be used to avoid
	   out of memory failures due to large images.

       apply_cropping bool (decoding,video)
	   Enable  cropping  if	 cropping  parameters  are  multiples  of  the
	   required  alignment	for  the  left	and  top  parameters.  If  the
	   alignment is	not met	the cropping  will  be	partially  applied  to
	   maintain  alignment.	  Default  is 1	(enabled).  Note: The required
	   alignment depends on	if "AV_CODEC_FLAG_UNALIGNED" is	 set  and  the
	   CPU.	 "AV_CODEC_FLAG_UNALIGNED"  cannot be changed from the command
	   line. Also hardware decoders	will not apply left/top	Cropping.

DECODERS
       Decoders	are configured elements	in FFmpeg which	allow the decoding  of
       multimedia streams.

       When you	configure your FFmpeg build, all the supported native decoders
       are  enabled by default.	Decoders requiring an external library must be
       enabled manually	via the	corresponding "--enable-lib" option.  You  can
       list    all    available	   decoders   using   the   configure	option
       "--list-decoders".

       You  can	 disable  all  the  decoders   with   the   configure	option
       "--disable-decoders"  and  selectively enable / disable single decoders
       with	  the	    options	   "--enable-decoder=DECODER"	     /
       "--disable-decoder=DECODER".

       The  option  "-decoders"	 of  the  ff*  tools  will display the list of
       enabled decoders.

VIDEO DECODERS
       A description  of  some	of  the	 currently  available  video  decoders
       follows.

   av1
       AOMedia Video 1 (AV1) decoder.

       Options

       operating_point
	   Select  an  operating  point	 of a scalable AV1 bitstream (0	- 31).
	   Default is 0.

   rawvideo
       Raw video decoder.

       This decoder decodes rawvideo streams.

       Options

       top top_field_first
	   Specify the assumed field type of the input video.

	   -1  the video is assumed to be progressive (default)

	   0   bottom-field-first is assumed

	   1   top-field-first is assumed

   libdav1d
       dav1d AV1 decoder.

       libdav1d	allows libavcodec to decode the	AOMedia	Video 1	 (AV1)	codec.
       Requires	 the  presence	of  the	 libdav1d  headers  and	library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       "--enable-libdav1d".

       Options

       The following options are supported by the libdav1d wrapper.

       framethreads
	   Set	amount	of  frame  threads to use during decoding. The default
	   value is 0 (autodetect).  This option is deprecated for libdav1d >=
	   1.0	and  will  be  removed	in  the	  future.   Use	  the	option
	   "max_frame_delay" and the global option "threads" instead.

       tilethreads
	   Set	amount	of  tile  threads  to use during decoding. The default
	   value is 0 (autodetect).  This option is deprecated for libdav1d >=
	   1.0 and will	be removed  in	the  future.  Use  the	global	option
	   "threads" instead.

       max_frame_delay
	   Set	max  amount  of	 frames	the decoder may	buffer internally. The
	   default value is 0 (autodetect).

       filmgrain
	   Apply film grain to the decoded video if present in the  bitstream.
	   Defaults  to	 the  internal default of the library.	This option is
	   deprecated and will be removed in the future. See the global	option
	   "export_side_data" to  export  Film	Grain  parameters  instead  of
	   applying it.

       oppoint
	   Select  an  operating  point	 of a scalable AV1 bitstream (0	- 31).
	   Defaults to the internal default of the library.

       alllayers
	   Output all spatial layers of	a scalable AV1 bitstream. The  default
	   value is false.

   libdavs2
       AVS2-P2/IEEE1857.4 video	decoder	wrapper.

       This  decoder  allows  libavcodec  to  decode  AVS2  streams with davs2
       library.

   libuavs3d
       AVS3-P2/IEEE1857.10 video decoder.

       libuavs3d allows	libavcodec  to	decode	AVS3  streams.	 Requires  the
       presence	 of  the  libuavs3d  headers and library during	configuration.
       You need	to explicitly configure	the build with "--enable-libuavs3d".

       Options

       The following option is supported by the	libuavs3d wrapper.

       frame_threads
	   Set amount of frame threads to use  during  decoding.  The  default
	   value is 0 (autodetect).

   QSV Decoders
       The family of Intel QuickSync Video decoders (VC1, MPEG-2, H.264, HEVC,
       JPEG/MJPEG, VP8,	VP9, AV1).

       Common Options

       The following options are supported by all qsv decoders.

       async_depth
	   Internal parallelization depth, the higher the value	the higher the
	   latency.

       gpu_copy
	   A GPU-accelerated copy between video	and system memory

	   default
	   on
	   off

       HEVC Options

       Extra options for hevc_qsv.

       load_plugin
	   A user plugin to load in an internal	session

	   none
	   hevc_sw
	   hevc_hw
       load_plugins
	   A :-separate	list of	hexadecimal plugin UIDs	to load	in an internal
	   session

   v210
       Uncompressed 4:2:2 10-bit decoder.

       Options

       custom_stride
	   Set the line	size of	the v210 data in bytes.	The default value is 0
	   (autodetect).  You  can  use	 the special -1	value for a strideless
	   v210	as seen	in BOXX	files.

AUDIO DECODERS
       A description  of  some	of  the	 currently  available  audio  decoders
       follows.

   ac3
       AC-3 audio decoder.

       This  decoder implements	part of	ATSC A/52:2010 and ETSI	TS 102 366, as
       well as the undocumented	RealAudio 3 (a.k.a. dnet).

       AC-3 Decoder Options

       -drc_scale value
	   Dynamic Range Scale Factor. The factor to apply  to	dynamic	 range
	   values  from	the AC-3 stream. This factor is	applied	exponentially.
	   The default value is	1.  There are 3	notable	scale factor ranges:

	   drc_scale ==	0
	       DRC disabled. Produces full range audio.

	   0 < drc_scale <= 1
	       DRC enabled.  Applies a	fraction  of  the  stream  DRC	value.
	       Audio reproduction is between full range	and full compression.

	   drc_scale > 1
	       DRC enabled. Applies drc_scale asymmetrically.  Loud sounds are
	       fully compressed.  Soft sounds are enhanced.

   flac
       FLAC audio decoder.

       This  decoder  aims  to	implement the complete FLAC specification from
       Xiph.

       FLAC Decoder options

       -use_buggy_lpc
	   The lavc FLAC encoder used to produce buggy streams with  high  lpc
	   values  (like  the default value). This option makes	it possible to
	   decode such streams correctly by using lavc's old buggy  lpc	 logic
	   for decoding.

   ffwavesynth
       Internal	wave synthesizer.

       This decoder generates wave patterns according to predefined sequences.
       Its use is purely internal and the format of the	data it	accepts	is not
       publicly	documented.

   libcelt
       libcelt decoder wrapper.

       libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio
       codec.  Requires	the presence of	the libcelt headers and	library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       "--enable-libcelt".

   libgsm
       libgsm decoder wrapper.

       libgsm allows libavcodec	to decode  the	GSM  full  rate	 audio	codec.
       Requires	 the  presence	of  the	 libgsm	 headers  and  library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libgsm".

       This decoder supports both the ordinary GSM and the Microsoft variant.

   libilbc
       libilbc decoder wrapper.

       libilbc	allows	libavcodec  to	decode	the Internet Low Bitrate Codec
       (iLBC) audio codec. Requires the	presence of the	 libilbc  headers  and
       library	during	configuration.	You  need  to explicitly configure the
       build with "--enable-libilbc".

       Options

       The following option is supported by the	libilbc	wrapper.

       enhance
	   Enable the enhancement of the decoded audio	when  set  to  1.  The
	   default value is 0 (disabled).

   libopencore-amrnb
       libopencore-amrnb decoder wrapper.

       libopencore-amrnb  allows  libavcodec to	decode the Adaptive Multi-Rate
       Narrowband  audio  codec.  Using	 it  requires  the  presence  of   the
       libopencore-amrnb headers and library during configuration. You need to
       explicitly configure the	build with "--enable-libopencore-amrnb".

       An  FFmpeg native decoder for AMR-NB exists, so users can decode	AMR-NB
       without this library.

   libopencore-amrwb
       libopencore-amrwb decoder wrapper.

       libopencore-amrwb allows	libavcodec to decode the  Adaptive  Multi-Rate
       Wideband	  audio	  codec.   Using  it  requires	the  presence  of  the
       libopencore-amrwb headers and library during configuration. You need to
       explicitly configure the	build with "--enable-libopencore-amrwb".

       An FFmpeg native	decoder	for AMR-WB exists, so users can	decode	AMR-WB
       without this library.

   libopus
       libopus decoder wrapper.

       libopus	allows	libavcodec to decode the Opus Interactive Audio	Codec.
       Requires	the  presence  of  the	libopus	 headers  and  library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       "--enable-libopus".

       An FFmpeg native	decoder	for Opus exists,  so  users  can  decode  Opus
       without this library.

SUBTITLES DECODERS
   libaribb24
       ARIB STD-B24 caption decoder.

       Implements profiles A and C of the ARIB STD-B24 standard.

       libaribb24 Decoder Options

       -aribb24-base-path path
	   Sets	the base path for the libaribb24 library. This is utilized for
	   reading  of	configuration  files (for custom unicode conversions),
	   and for dumping of non-text symbols as images under that location.

	   Unset by default.

       -aribb24-skip-ruby-text boolean
	   Tells the decoder wrapper to	skip text blocks  that	contain	 half-
	   height ruby text.

	   Enabled by default.

   libaribcaption
       Yet  another ARIB STD-B24 caption decoder using external	libaribcaption
       library.

       Implements profiles A and C  of	the  Japanse  ARIB  STD-B24  standard,
       Brazilian ABNT NBR 15606-1, and Philippines version of ISDB-T.

       Requires	 the  presence	of  the	 libaribcaption	 headers  and  library
       (<https://github.com/xqq/libaribcaption>)  during  configuration.   You
       need  to	explicitly configure the build with "--enable-libaribcaption".
       If both	libaribb24  and	 libaribcaption	 are  enabled,	libaribcaption
       decoder precedes.

       libaribcaption Decoder Options

       -sub_type subtitle_type
	   Specifies the format	of the decoded subtitles.

	   bitmap
	       Graphical image.

	   ass ASS formatted text.

	   text
	       Simple text based output	without	formatting.

	   The	default	 is  ass  as same as libaribb24	decoder.  Some present
	   players (e.g., mpv) expect ASS format for ARIB caption.

       -caption_encoding encoding_scheme
	   Specifies the encoding scheme of input subtitle text.

	   auto
	       Automatically detect text encoding (default).

	   jis 8bit-char JIS encoding defined in ARIB STD B24.	This  encoding
	       used in Japan for ISDB captions.

	   utf8
	       UTF-8  encoding defined in ARIB STD B24.	 This encoding is used
	       in Philippines for ISDB-T captions.

	   latin
	       Latin character encoding	defined	in  ABNT  NBR  15606-1.	  This
	       encoding	is used	in South America for SBTVD / ISDB-Tb captions.

       -font font_name[,font_name2,...]
	   Specify  comma-separated  list  of font family names	to be used for
	   bitmap or ass type subtitle rendering.  Only	 first	font  name  is
	   used	for ass	type subtitle.

	   If not specified, use internaly defined default font	family.

       -ass_single_rect	boolean
	   ARIB	 STD-B24  specifies  that  some	 captions  may be displayed at
	   different positions at a time  (multi-rectangle  subtitle).	 Since
	   some	 players  (e.g., old mpv) can't	handle multiple	ASS rectangles
	   in a	single AVSubtitle, or multiple ASS rectangles of indeterminate
	   duration with the same start	timestamp, this	option can change  the
	   behavior  so	 that  all  the	 texts	are  displayed in a single ASS
	   rectangle.

	   The default is false.

	   If  your  player  cannot  handle  AVSubtitles  with	multiple   ASS
	   rectangles	properly,   set	  this	 option	  to  true  or	define
	   ASS_SINGLE_RECT=1 to	change default behavior	at compilation.

       -force_outline_text boolean
	   Specify whether always  render  outline  text  for  all  characters
	   regardless of the indication	by charactor style.

	   The default is false.

       -outline_width number (0.0 - 3.0)
	   Specify width for outline text, in dots (relative).

	   The default is 1.5.

       -ignore_background boolean
	   Specify whether to ignore background	color rendering.

	   The default is false.

       -ignore_ruby boolean
	   Specify  whether  to	 ignore	 rendering  for	 ruby-like  (furigana)
	   characters.

	   The default is false.

       -replace_drcs boolean
	   Specify whether to  render  replaced	 DRCS  characters  as  Unicode
	   characters.

	   The default is true.

       -replace_msz_ascii boolean
	   Specify  whether to replace MSZ (Middle Size; half width) fullwidth
	   alphanumerics with halfwidth	alphanumerics.

	   The default is true.

       -replace_msz_japanese boolean
	   Specify whether to replace  some  MSZ  (Middle  Size;  half	width)
	   fullwidth japanese special characters with halfwidth	ones.

	   The default is true.

       -replace_msz_glyph boolean
	   Specify whether to replace MSZ (Middle Size;	half width) characters
	   with	 halfwidth glyphs if the fonts supports	it.  This option works
	   under FreeType or DirectWrite renderer with Adobe-Japan1  compliant
	   fonts.  e.g., IBM Plex Sans JP, Morisawa BIZ	UDGothic, Morisawa BIZ
	   UDMincho, Yu	Gothic,	Yu Mincho, and Meiryo.

	   The default is true.

       -canvas_size image_size
	   Specify  the	 resolution  of	 the  canvas  to  render subtitles to;
	   usually, this should	be frame  size	of  input  video.   This  only
	   applies when	"-subtitle_type" is set	to bitmap.

	   The	libaribcaption	decoder	 assumes  input	 frame size for	bitmap
	   rendering as	below:

	   1.  PROFILE_A : 1440	x 1080 with SAR	(PAR) 4:3

	   2.  PROFILE_C : 320 x 180 with SAR (PAR) 1:1

	   If  actual  frame  size  of	input  video  does  not	 match	 above
	   assumption,	the  rendered  captions	may be distorted.  To make the
	   captions undistorted, add "-canvas_size" option to  specify	actual
	   input video size.

	   Note	 that the "-canvas_size" option	is not required	for video with
	   different size but same aspect ratio.  In such cases,  the  caption
	   will	 be stretched or shrunk	to actual video	size if	"-canvas_size"
	   option is not specified.  If	 "-canvas_size"	 option	 is  specified
	   with	 different  size,  the	caption	will be	stretched or shrunk as
	   specified size with calculated SAR.

       libaribcaption decoder usage examples

       Display MPEG-TS file with ARIB subtitle by "ffplay" tool:

	       ffplay -sub_type	bitmap MPEG.TS

       Display MPEG-TS file with input frame size 1920x1080 by "ffplay"	tool:

	       ffplay -sub_type	bitmap -canvas_size 1920x1080 MPEG.TS

       Embed ARIB subtitle in transcoded video:

	       ffmpeg -sub_type	bitmap -i src.m2t -filter_complex "[0:v][0:s]overlay" -vcodec h264 dest.mp4

   dvbsub
       Options

       compute_clut
	   -2  Compute clut once if no matching	CLUT is	in the stream.

	   -1  Compute clut if no matching CLUT	is in the stream.

	   0   Never compute CLUT

	   1   Always compute CLUT  and	 override  the	one  provided  in  the
	       stream.

       dvb_substream
	   Selects  the	 dvb  substream,  or  all  substreams  if  -1 which is
	   default.

   dvdsub
       This codec  decodes  the	 bitmap	 subtitles  used  in  DVDs;  the  same
       subtitles  can  also be found in	VobSub file pairs and in some Matroska
       files.

       Options

       palette
	   Specify the global palette used by  the  bitmaps.  When  stored  in
	   VobSub,  the	 palette  is  normally specified in the	index file; in
	   Matroska, the palette is stored in the codec	extra-data in the same
	   format as in	VobSub.	In DVDs, the palette  is  stored  in  the  IFO
	   file,  and  therefore  not  available  when reading from dumped VOB
	   files.

	   The format for this	option	is  a  string  containing  16  24-bits
	   hexadecimal	numbers	 (without  0x prefix) separated	by commas, for
	   example "0d00ee, ee450d, 101010, eaeaea,  0ce60b,  ec14ed,  ebff0b,
	   0d617a,  7b7b7b,  d1d1d1,  7b2a0e,  0d950c, 0f007b, cf0dec, cfa80c,
	   7c127b".

       ifo_palette
	   Specify the IFO file	from which the	global	palette	 is  obtained.
	   (experimental)

       forced_subs_only
	   Only	 decode	 subtitle  entries  marked as forced. Some titles have
	   forced and non-forced subtitles in the  same	 track.	 Setting  this
	   flag	to 1 will only keep the	forced subtitles. Default value	is 0.

   libzvbi-teletext
       Libzvbi allows libavcodec to decode DVB teletext	pages and DVB teletext
       subtitles.  Requires  the  presence  of the libzvbi headers and library
       during configuration. You need to explicitly configure the  build  with
       "--enable-libzvbi".

       Options

       txt_page
	   List	 of  teletext  page numbers to decode. Pages that do not match
	   the specified list are dropped. You may use the special "*"	string
	   to  match  all  pages,  or  "subtitle" to match all subtitle	pages.
	   Default value is *.

       txt_default_region
	   Set default character set used for decoding,	a value	between	0  and
	   87  (see  ETS  300 706, Section 15, Table 32). Default value	is -1,
	   which does not override the libzvbi default.	This option is	needed
	   for	some  legacy  level  1.0 transmissions which cannot signal the
	   proper charset.

       txt_chop_top
	   Discards the	top teletext line. Default value is 1.

       txt_format
	   Specifies the format	of the decoded subtitles.

	   bitmap
	       The default format, you should use  this	 for  teletext	pages,
	       because	certain	 graphics  and	colors	cannot be expressed in
	       simple text or even ASS.

	   text
	       Simple text based output	without	formatting.

	   ass Formatted ASS output, subtitle pages  and  teletext  pages  are
	       returned	 in different styles, subtitle pages are stripped down
	       to text,	but an effort is made to keep the text	alignment  and
	       the formatting.

       txt_left
	   X offset of generated bitmaps, default is 0.

       txt_top
	   Y offset of generated bitmaps, default is 0.

       txt_chop_spaces
	   Chops  leading and trailing spaces and removes empty	lines from the
	   generated text. This	option is useful for teletext based  subtitles
	   where empty spaces may be present at	the start or at	the end	of the
	   lines  or  empty  lines  may	 be present between the	subtitle lines
	   because of double-sized teletext characters.	 Default value is 1.

       txt_duration
	   Sets	 the  display  duration	 of  the  decoded  teletext  pages  or
	   subtitles in	milliseconds. Default value is -1 which	means infinity
	   or until the	next subtitle event comes.

       txt_transparent
	   Force  transparent  background  of  the generated teletext bitmaps.
	   Default value is 0 which means an opaque background.

       txt_opacity
	   Sets	 the  opacity  (0-255)	of   the   teletext   background.   If
	   txt_transparent  is	not  set, it only affects characters between a
	   start box and an end	box, typically subtitles. Default value	 is  0
	   if txt_transparent is set, 255 otherwise.

ENCODERS
       Encoders	 are configured	elements in FFmpeg which allow the encoding of
       multimedia streams.

       When you	configure your FFmpeg build, all the supported native encoders
       are enabled by default. Encoders	requiring an external library must  be
       enabled	manually  via the corresponding	"--enable-lib" option. You can
       list   all   available	encoders   using    the	   configure	option
       "--list-encoders".

       You   can   disable   all   the	encoders  with	the  configure	option
       "--disable-encoders" and	selectively enable / disable  single  encoders
       with	   the	      options	    "--enable-encoder=ENCODER"	     /
       "--disable-encoder=ENCODER".

       The option "-encoders" of the  ff*  tools  will	display	 the  list  of
       enabled encoders.

AUDIO ENCODERS
       A  description  of  some	 of  the  currently  available	audio encoders
       follows.

   aac
       Advanced	Audio Coding (AAC) encoder.

       This encoder is the default  AAC	 encoder,  natively  implemented  into
       FFmpeg.

       Options

       b   Set	bit  rate  in  bits/s.	Setting	 this  automatically activates
	   constant bit	rate (CBR) mode. If this option	is unspecified	it  is
	   set to 128kbps.

       q   Set	quality	for variable bit rate (VBR) mode. This option is valid
	   only	using the ffmpeg  command-line	tool.  For  library  interface
	   users, use global_quality.

       cutoff
	   Set	cutoff	frequency.  If	unspecified  will allow	the encoder to
	   dynamically adjust the cutoff to improve clarity on low bitrates.

       aac_coder
	   Set AAC encoder coding method. Possible values:

	   twoloop
	       Two loop	searching (TLS)	method.	This is	the default method.

	       This method first sets quantizers depending on band  thresholds
	       and  then  tries	 to  find  an optimal combination by adding or
	       subtracting a specific value from all quantizers	and  adjusting
	       some  individual	quantizer a little.  Will tune itself based on
	       whether aac_is, aac_ms and aac_pns are enabled.

	   anmr
	       Average noise to	mask ratio (ANMR) trellis-based	solution.

	       This is an experimental coder which currently produces a	 lower
	       quality,	 is  more  unstable  and  is  slower  than the default
	       twoloop coder but has potential.	 Currently has no support  for
	       the aac_is or aac_pns options.  Not currently recommended.

	   fast
	       Constant	quantizer method.

	       Uses a cheaper version of twoloop algorithm that	doesn't	try to
	       do  as  many  clever adjustments. Worse with low	bitrates (less
	       than 64kbps), but is better and much faster at higher bitrates.

       aac_ms
	   Sets	mid/side  coding  mode.	 The  default  value  of  "auto"  will
	   automatically  use  M/S  with  bands	 which	will benefit from such
	   coding. Can be forced for all bands using the value "enable", which
	   is mainly useful for	debugging or disabled using "disable".

       aac_is
	   Sets	intensity stereo coding	tool usage. By default,	 it's  enabled
	   and	will automatically toggle IS for similar pairs of stereo bands
	   if it's beneficial.	Can be disabled	for debugging by  setting  the
	   value to "disable".

       aac_pns
	   Uses	 perceptual  noise  substitution  to  replace low entropy high
	   frequency bands with	imperceptible white noise during the  decoding
	   process.  By	 default,  it's	 enabled,  but	can  be	 disabled  for
	   debugging purposes by using "disable".

       aac_tns
	   Enables the use of a	multitap FIR filter which  spans  through  the
	   high	frequency bands	to hide	quantization noise during the encoding
	   process  and	 is  reverted  by  the	decoder. As well as decreasing
	   unpleasant artifacts	in  the	 high  range  this  also  reduces  the
	   entropy  in	the  high bands	and allows for more bits to be used by
	   the mid-low bands. By default it's enabled but can be disabled  for
	   debugging by	setting	the option to "disable".

       aac_ltp
	   Enables  the	 use  of  the  long  term  prediction  extension which
	   increases coding efficiency in very low bandwidth  situations  such
	   as  encoding	 of  voice  or	solo piano music by extending constant
	   harmonic peaks in bands throughout frames. This option  is  implied
	   by  profile:a  aac_low  and	is  incompatible with aac_pred.	Use in
	   conjunction with -ar	to decrease the	samplerate.

       aac_pred
	   Enables the use of a	more traditional style of prediction where the
	   spectral coefficients transmitted are replaced by the difference of
	   the	 current   coefficients	  minus	  the	previous   "predicted"
	   coefficients.  In theory and	sometimes in practice this can improve
	   quality for low to mid bitrate  audio.   This  option  implies  the
	   aac_main profile and	is incompatible	with aac_ltp.

       profile
	   Sets	the encoding profile, possible values:

	   aac_low
	       The   default,	AAC  "Low-complexity"  profile.	 Is  the  most
	       compatible and produces decent quality.

	   mpeg2_aac_low
	       Equivalent  to  "-profile:a  aac_low  -aac_pns  0".   PNS   was
	       introduced with the MPEG4 specifications.

	   aac_ltp
	       Long term prediction profile, is	enabled	by and will enable the
	       aac_ltp option. Introduced in MPEG4.

	   aac_main
	       Main-type prediction profile, is	enabled	by and will enable the
	       aac_pred	option.	Introduced in MPEG2.

	   If this option is unspecified it is set to aac_low.

   ac3 and ac3_fixed
       AC-3 audio encoders.

       These encoders implement	part of	ATSC A/52:2010 and ETSI	TS 102 366, as
       well as the undocumented	RealAudio 3 (a.k.a. dnet).

       The  ac3	 encoder uses floating-point math, while the ac3_fixed encoder
       only uses fixed-point integer math. This	does  not  mean	 that  one  is
       always  faster,	just  that  one	or the other may be better suited to a
       particular system. The ac3_fixed	encoder	is not the default  codec  for
       any of the output formats, so it	must be	specified explicitly using the
       option "-acodec ac3_fixed" in order to use it.

       AC-3 Metadata

       The  AC-3 metadata options are used to set parameters that describe the
       audio, but in most cases	do not affect the audio	encoding itself.  Some
       of  the	options	 do  directly  affect  or  influence  the decoding and
       playback	 of  the  resulting  bitstream,	 while	others	are  just  for
       informational  purposes.	 A  few	 of  the  options will add bits	to the
       output stream that could	otherwise be used for  audio  data,  and  will
       thus  affect  the  quality  of  the  output.  Those  will  be indicated
       accordingly with	a note in the option list below.

       These parameters	are described in detail	in several  publicly-available
       documents.

       *<<http://www.atsc.org/cms/standards/a_52-2010.pdf>>
       *<<http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf>>
       *<<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf>>
       *<<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf>>

       Metadata	Control	Options

       -per_frame_metadata boolean
	   Allow Per-Frame Metadata. Specifies if the encoder should check for
	   changing metadata for each frame.

	   0   The  metadata  values  set  at  initialization will be used for
	       every frame in the stream. (default)

	   1   Metadata	values can be changed before encoding each frame.

       Downmix Levels

       -center_mixlev level
	   Center Mix Level. The amount	of gain	the decoder  should  apply  to
	   the	center channel when downmixing to stereo. This field will only
	   be written to the bitstream if a center  channel  is	 present.  The
	   value is specified as a scale factor. There are 3 valid values:

	   0.707
	       Apply -3dB gain

	   0.595
	       Apply -4.5dB gain (default)

	   0.500
	       Apply -6dB gain

       -surround_mixlev	level
	   Surround  Mix Level.	The amount of gain the decoder should apply to
	   the surround	channel(s) when	downmixing to stereo. This field  will
	   only	 be  written to	the bitstream if one or	more surround channels
	   are present.	The value is specified as a scale factor.  There are 3
	   valid values:

	   0.707
	       Apply -3dB gain

	   0.500
	       Apply -6dB gain (default)

	   0.000
	       Silence Surround	Channel(s)

       Audio Production	Information

       Audio Production	Information is	optional  information  describing  the
       mixing  environment.   Either none or both of the fields	are written to
       the bitstream.

       -mixing_level number
	   Mixing Level. Specifies peak	sound  pressure	 level	(SPL)  in  the
	   production  environment when	the mix	was mastered. Valid values are
	   80 to 111, or -1 for	unknown	or not indicated. The default value is
	   -1,	but  that  value  cannot  be  used  if	the  Audio  Production
	   Information	 is  written  to  the  bitstream.  Therefore,  if  the
	   "room_type" option is not the  default  value,  the	"mixing_level"
	   option must not be -1.

       -room_type type
	   Room	 Type. Describes the equalization used during the final	mixing
	   session at the studio or on the dubbing stage. A large  room	 is  a
	   dubbing  stage  with	 the industry standard X-curve equalization; a
	   small room has flat equalization.  This field will not  be  written
	   to  the  bitstream  if  both	 the  "mixing_level"  option  and  the
	   "room_type" option have the default values.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   large
	       Large Room

	   2
	   small
	       Small Room

       Other Metadata Options

       -copyright boolean
	   Copyright Indicator.	Specifies whether a copyright exists for  this
	   audio.

	   0
	   off No Copyright Exists (default)

	   1
	   on  Copyright Exists

       -dialnorm value
	   Dialogue  Normalization.  Indicates	how  far  the average dialogue
	   level of the	program	is below digital 100%  full  scale  (0	dBFS).
	   This	 parameter  determines a level shift during audio reproduction
	   that	sets the average volume	of the dialogue	to a preset level. The
	   goal	is to match volume level between program sources. A  value  of
	   -31dB will result in	no volume level	change,	relative to the	source
	   volume,  during  audio reproduction.	Valid values are whole numbers
	   in the range	-31 to -1, with	-31 being the default.

       -dsur_mode mode
	   Dolby Surround Mode.	Specifies whether the stereo signal uses Dolby
	   Surround (Pro Logic). This  field  will  only  be  written  to  the
	   bitstream if	the audio stream is stereo. Using this option does NOT
	   mean	the encoder will actually apply	Dolby Surround processing.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   off Not Dolby Surround Encoded

	   2
	   on  Dolby Surround Encoded

       -original boolean
	   Original Bit	Stream Indicator. Specifies whether this audio is from
	   the original	source and not a copy.

	   0
	   off Not Original Source

	   1
	   on  Original	Source (default)

       Extended	Bitstream Information

       The  extended  bitstream	 options  are part of the Alternate Bit	Stream
       Syntax as specified in Annex D of the A/52:2010 standard. It is grouped
       into 2 parts.  If any one parameter in a	group is specified, all	values
       in that group will be written to	the  bitstream.	  Default  values  are
       used  for  those	 that are written but have not been specified.	If the
       mixing levels are written, the decoder will use these values instead of
       the ones	specified in the "center_mixlev" and "surround_mixlev" options
       if it supports the Alternate Bit	Stream Syntax.

       Extended	Bitstream Information -	Part 1

       -dmix_mode mode
	   Preferred Stereo Downmix Mode. Allows the  user  to	select	either
	   Lt/Rt  (Dolby  Surround)  or	Lo/Ro (normal stereo) as the preferred
	   stereo downmix mode.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   ltrt
	       Lt/Rt Downmix Preferred

	   2
	   loro
	       Lo/Ro Downmix Preferred

       -ltrt_cmixlev level
	   Lt/Rt Center	Mix Level. The amount of gain the decoder should apply
	   to the center channel when downmixing to stereo in Lt/Rt mode.

	   1.414
	       Apply +3dB gain

	   1.189
	       Apply +1.5dB gain

	   1.000
	       Apply 0dB gain

	   0.841
	       Apply -1.5dB gain

	   0.707
	       Apply -3.0dB gain

	   0.595
	       Apply -4.5dB gain (default)

	   0.500
	       Apply -6.0dB gain

	   0.000
	       Silence Center Channel

       -ltrt_surmixlev level
	   Lt/Rt Surround Mix Level. The amount	of  gain  the  decoder	should
	   apply to the	surround channel(s) when downmixing to stereo in Lt/Rt
	   mode.

	   0.841
	       Apply -1.5dB gain

	   0.707
	       Apply -3.0dB gain

	   0.595
	       Apply -4.5dB gain

	   0.500
	       Apply -6.0dB gain (default)

	   0.000
	       Silence Surround	Channel(s)

       -loro_cmixlev level
	   Lo/Ro Center	Mix Level. The amount of gain the decoder should apply
	   to the center channel when downmixing to stereo in Lo/Ro mode.

	   1.414
	       Apply +3dB gain

	   1.189
	       Apply +1.5dB gain

	   1.000
	       Apply 0dB gain

	   0.841
	       Apply -1.5dB gain

	   0.707
	       Apply -3.0dB gain

	   0.595
	       Apply -4.5dB gain (default)

	   0.500
	       Apply -6.0dB gain

	   0.000
	       Silence Center Channel

       -loro_surmixlev level
	   Lo/Ro  Surround  Mix	 Level.	 The amount of gain the	decoder	should
	   apply to the	surround channel(s) when downmixing to stereo in Lo/Ro
	   mode.

	   0.841
	       Apply -1.5dB gain

	   0.707
	       Apply -3.0dB gain

	   0.595
	       Apply -4.5dB gain

	   0.500
	       Apply -6.0dB gain (default)

	   0.000
	       Silence Surround	Channel(s)

       Extended	Bitstream Information -	Part 2

       -dsurex_mode mode
	   Dolby Surround EX Mode. Indicates whether  the  stream  uses	 Dolby
	   Surround  EX	(7.1 matrixed to 5.1). Using this option does NOT mean
	   the encoder will actually apply Dolby Surround EX processing.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   on  Dolby Surround EX Off

	   2
	   off Dolby Surround EX On

       -dheadphone_mode	mode
	   Dolby Headphone Mode.  Indicates  whether  the  stream  uses	 Dolby
	   Headphone  encoding	(multi-channel	matrixed  to  2.0 for use with
	   headphones).	Using this option  does	 NOT  mean  the	 encoder  will
	   actually apply Dolby	Headphone processing.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   on  Dolby Headphone Off

	   2
	   off Dolby Headphone On

       -ad_conv_type type
	   A/D	Converter Type.	Indicates whether the audio has	passed through
	   HDCD	A/D conversion.

	   0
	   standard
	       Standard	A/D Converter (default)

	   1
	   hdcd
	       HDCD A/D	Converter

       Other AC-3 Encoding Options

       -stereo_rematrixing boolean
	   Stereo Rematrixing. Enables/Disables	use of rematrixing for	stereo
	   input.  This	 is an optional	AC-3 feature that increases quality by
	   selectively encoding	the  left/right	 channels  as  mid/side.  This
	   option  is enabled by default, and it is highly recommended that it
	   be left as enabled except for testing purposes.

       cutoff frequency
	   Set lowpass cutoff frequency. If unspecified, the encoder selects a
	   default determined by various other encoding	parameters.

       Floating-Point-Only AC-3	Encoding Options

       These options are only valid for	the floating-point encoder and do  not
       exist for the fixed-point encoder due to	the corresponding features not
       being implemented in fixed-point.

       -channel_coupling boolean
	   Enables/Disables use	of channel coupling, which is an optional AC-3
	   feature   that   increases  quality	by  combining  high  frequency
	   information from multiple channels into a single channel. The  per-
	   channel  high  frequency  information is sent with less accuracy in
	   both	the frequency and time domains.	This allows more  bits	to  be
	   used	 for  lower frequencies	while preserving enough	information to
	   reconstruct the high	frequencies. This option is enabled by default
	   for the floating-point encoder and  should  generally  be  left  as
	   enabled except for testing purposes or to increase encoding speed.

	   -1
	   auto
	       Selected	by Encoder (default)

	   0
	   off Disable Channel Coupling

	   1
	   on  Enable Channel Coupling

       -cpl_start_band number
	   Coupling  Start  Band. Sets the channel coupling start band,	from 1
	   to 15. If a value higher than the bandwidth is  used,  it  will  be
	   reduced  to 1 less than the coupling	end band. If auto is used, the
	   start band will be determined by the	encoder	based on the bit rate,
	   sample rate,	and channel layout.  This  option  has	no  effect  if
	   channel coupling is disabled.

	   -1
	   auto
	       Selected	by Encoder (default)

   flac
       FLAC (Free Lossless Audio Codec)	Encoder

       Options

       The following options are supported by FFmpeg's flac encoder.

       compression_level
	   Sets	 the  compression level, which chooses defaults	for many other
	   options if they are not set explicitly. Valid values	are from 0  to
	   12, 5 is the	default.

       frame_size
	   Sets	the size of the	frames in samples per channel.

       lpc_coeff_precision
	   Sets	 the LPC coefficient precision,	valid values are from 1	to 15,
	   15 is the default.

       lpc_type
	   Sets	the first stage	LPC algorithm

	   none
	       LPC is not used

	   fixed
	       fixed LPC coefficients

	   levinson
	   cholesky
       lpc_passes
	   Number of passes to	use  for  Cholesky  factorization  during  LPC
	   analysis

       min_partition_order
	   The minimum partition order

       max_partition_order
	   The maximum partition order

       prediction_order_method
	   estimation
	   2level
	   4level
	   8level
	   search
	       Bruteforce search

	   log
       ch_mode
	   Channel mode

	   auto
	       The mode	is chosen automatically	for each frame

	   indep
	       Channels	are independently coded

	   left_side
	   right_side
	   mid_side
       exact_rice_parameters
	   Chooses if rice parameters are calculated exactly or	approximately.
	   if set to 1 then they are chosen exactly, which slows the code down
	   slightly and	improves compression slightly.

       multi_dim_quant
	   Multi  Dimensional  Quantization.  If set to	1 then a 2nd stage LPC
	   algorithm  is  applied  after  the  first  stage  to	 finetune  the
	   coefficients. This is quite slow and	slightly improves compression.

   opus
       Opus encoder.

       This  is	 a native FFmpeg encoder for the Opus format. Currently	its in
       development and only implements the CELT	part of	the codec. Its quality
       is usually worse	and at best is equal to	the libopus encoder.

       Options

       b   Set bit rate	in bits/s.  If	unspecified  it	 uses  the  number  of
	   channels and	the layout to make a good guess.

       opus_delay
	   Sets	the maximum delay in milliseconds. Lower delays	than 20ms will
	   very	quickly	decrease quality.

   libfdk_aac
       libfdk-aac AAC (Advanced	Audio Coding) encoder wrapper.

       The libfdk-aac library is based on the Fraunhofer FDK AAC code from the
       Android project.

       Requires	 the  presence	of  the	 libfdk-aac headers and	library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libfdk-aac". The library is also incompatible with GPL, so if
       you  allow  the	use  of	 GPL,  you should configure with "--enable-gpl
       --enable-nonfree	--enable-libfdk-aac".

       This encoder has	support	for the	AAC-HE profiles.

       VBR encoding, enabled through the vbr  or  flags	 +qscale  options,  is
       experimental and	only works with	some combinations of parameters.

       Support	for encoding 7.1 audio is only available with libfdk-aac 0.1.3
       or higher.

       For    more    information    see    the	    fdk-aac	project	    at
       <http://sourceforge.net/p/opencore-amr/fdk-aac/>.

       Options

       The following options are mapped	on the shared FFmpeg codec options.

       b   Set bit rate	in bits/s. If the bitrate is not explicitly specified,
	   it  is  automatically  set  to  a  suitable	value depending	on the
	   selected profile.

	   In case VBR mode is enabled the option is ignored.

       ar  Set audio sampling rate (in Hz).

       channels
	   Set the number of audio channels.

       flags +qscale
	   Enable fixed	quality, VBR (Variable Bit Rate) mode.	Note that  VBR
	   is implicitly enabled when the vbr value is positive.

       cutoff
	   Set	cutoff frequency. If not specified (or explicitly set to 0) it
	   will	use a value automatically computed  by	the  library.  Default
	   value is 0.

       profile
	   Set audio profile.

	   The following profiles are recognized:

	   aac_low
	       Low Complexity AAC (LC)

	   aac_he
	       High Efficiency AAC (HE-AAC)

	   aac_he_v2
	       High Efficiency AAC version 2 (HE-AACv2)

	   aac_ld
	       Low Delay AAC (LD)

	   aac_eld
	       Enhanced	Low Delay AAC (ELD)

	   If not specified it is set to aac_low.

       The following are private options of the	libfdk_aac encoder.

       afterburner
	   Enable  afterburner feature if set to 1, disabled if	set to 0. This
	   improves the	quality	but also the required processing power.

	   Default value is 1.

       eld_sbr
	   Enable SBR (Spectral	 Band  Replication)  for  ELD  if  set	to  1,
	   disabled if set to 0.

	   Default value is 0.

       eld_v2
	   Enable ELDv2	(LD-MPS	extension for ELD stereo signals) for ELDv2 if
	   set to 1, disabled if set to	0.

	   Note	   that	   option    is	  available   when   fdk-aac   version
	   (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2)	     >
	   (4.0.0).

	   Default value is 0.

       signaling
	   Set SBR/PS signaling	style.

	   It can assume one of	the following values:

	   default
	       choose  signaling implicitly (explicit hierarchical by default,
	       implicit	if global header is disabled)

	   implicit
	       implicit	backwards compatible signaling

	   explicit_sbr
	       explicit	SBR, implicit PS signaling

	   explicit_hierarchical
	       explicit	hierarchical signaling

	   Default value is default.

       latm
	   Output LATM/LOAS encapsulated data if set to	1, disabled if set  to
	   0.

	   Default value is 0.

       header_period
	   Set	StreamMuxConfig	 and  PCE  repetition  period  (in frames) for
	   sending in-band configuration buffers  within  LATM/LOAS  transport
	   layer.

	   Must	be a 16-bits non-negative integer.

	   Default value is 0.

       vbr Set VBR mode, from 1	to 5. 1	is lowest quality (though still	pretty
	   good)  and 5	is highest quality. A value of 0 will disable VBR, and
	   CBR (Constant Bit Rate) is enabled.

	   Currently only the aac_low profile supports VBR encoding.

	   VBR modes 1-5 correspond  to	 roughly  the  following  average  bit
	   rates:

	   1   32 kbps/channel

	   2   40 kbps/channel

	   3   48-56 kbps/channel

	   4   64 kbps/channel

	   5   about 80-96 kbps/channel

	   Default value is 0.

       frame_length
	   Set	the  audio  frame  length  in  samples.	 Default  value	is the
	   internal  default  of  the  library.	  Refer	  to   the   library's
	   documentation for information about supported values.

       Examples

          Use	ffmpeg	to  convert  an	 audio file to VBR AAC in an M4A (MP4)
	   container:

		   ffmpeg -i input.wav -codec:a	libfdk_aac -vbr	3 output.m4a

          Use ffmpeg to convert an audio file to CBR 64k kbps AAC, using  the
	   High-Efficiency AAC profile:

		   ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a

   libmp3lame
       LAME (Lame Ain't	an MP3 Encoder)	MP3 encoder wrapper.

       Requires	 the  presence	of  the	 libmp3lame headers and	library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libmp3lame".

       See  libshine  for  a  fixed-point  MP3	encoder, although with a lower
       quality.

       Options

       The following options are supported  by	the  libmp3lame	 wrapper.  The
       lame-equivalent of the options are listed in parentheses.

       b (-b)
	   Set	bitrate	 expressed in bits/s for CBR or	ABR. LAME "bitrate" is
	   expressed in	kilobits/s.

       q (-V)
	   Set constant	quality	setting	for VBR. This  option  is  valid  only
	   using  the  ffmpeg  command-line tool. For library interface	users,
	   use global_quality.

       compression_level (-q)
	   Set algorithm quality. Valid	arguments  are	integers  in  the  0-9
	   range,  with	 0  meaning highest quality but	slowest, and 9 meaning
	   fastest while producing the worst quality.

       cutoff (--lowpass)
	   Set	lowpass	 cutoff	 frequency.  If	  unspecified,	 the   encoder
	   dynamically adjusts the cutoff.

       reservoir
	   Enable use of bit reservoir when set	to 1. Default value is 1. LAME
	   has	this  enabled by default, but can be overridden	by use --nores
	   option.

       joint_stereo (-m	j)
	   Enable the encoder to use (on a frame by frame  basis)  either  L/R
	   stereo or mid/side stereo. Default value is 1.

       abr (--abr)
	   Enable  the	encoder	 to use	ABR when set to	1. The lame --abr sets
	   the target bitrate, while this options only tells FFmpeg to use ABR
	   still relies	on b to	set bitrate.

       copyright (-c)
	   Set MPEG audio copyright flag when set to 1.	The default value is 0
	   (disabled).

       original	(-o)
	   Set MPEG audio original flag	when set to 1. The default value is  1
	   (enabled).

   libopencore-amrnb
       OpenCORE	Adaptive Multi-Rate Narrowband encoder.

       Requires	 the  presence	of  the	 libopencore-amrnb headers and library
       during configuration. You need to explicitly configure the  build  with
       "--enable-libopencore-amrnb --enable-version3".

       This  is	a mono-only encoder. Officially	it only	supports 8000Hz	sample
       rate, but you can override it by	setting	strict to unofficial or	lower.

       Options

       b   Set bitrate in bits per second. Only	 the  following	 bitrates  are
	   supported,  otherwise  libavcodec  will  round to the nearest valid
	   bitrate.

	   4750
	   5150
	   5900
	   6700
	   7400
	   7950
	   10200
	   12200
       dtx Allow discontinuous transmission (generate comfort noise) when  set
	   to 1. The default value is 0	(disabled).

   libopus
       libopus Opus Interactive	Audio Codec encoder wrapper.

       Requires	 the  presence	of  the	 libopus  headers  and	library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libopus".

       Option Mapping

       Most  libopus options are modelled after	the opusenc utility from opus-
       tools. The following is an  option  mapping  chart  describing  options
       supported  by  the  libopus  wrapper,  and  their opusenc-equivalent in
       parentheses.

       b (bitrate)
	   Set the bit rate in bits/s.	FFmpeg's  b  option  is	 expressed  in
	   bits/s, while opusenc's bitrate in kilobits/s.

       vbr (vbr, hard-cbr, and cvbr)
	   Set	VBR  mode.  The	 FFmpeg	 vbr  option  has  the following valid
	   arguments, with the opusenc equivalent options in parentheses:

	   off (hard-cbr)
	       Use constant bit	rate encoding.

	   on (vbr)
	       Use variable bit	rate encoding (the default).

	   constrained (cvbr)
	       Use constrained variable	bit rate encoding.

       compression_level (comp)
	   Set encoding	algorithm complexity. Valid options  are  integers  in
	   the	0-10  range.  0	 gives	the fastest encodes but	lower quality,
	   while 10 gives  the	highest	 quality  but  slowest	encoding.  The
	   default is 10.

       frame_duration (framesize)
	   Set maximum frame size, or duration of a frame in milliseconds. The
	   argument  must  be  exactly	the following: 2.5, 5, 10, 20, 40, 60.
	   Smaller frame sizes achieve lower latency but  less	quality	 at  a
	   given  bitrate.   Sizes  greater  than 20ms are only	interesting at
	   fairly low bitrates.	 The default is	20ms.

       packet_loss (expect-loss)
	   Set expected	packet loss percentage.	The default is 0.

       fec (n/a)
	   Enable inband forward error correction. packet_loss	must  be  non-
	   zero	  to   take  advantage	-  frequency  of  FEC  'side-data'  is
	   proportional	to expected packet loss.  Default is disabled.

       application (N.A.)
	   Set intended	application type. Valid	options	are listed below:

	   voip
	       Favor improved speech intelligibility.

	   audio
	       Favor faithfulness to the input (the default).

	   lowdelay
	       Restrict	to only	the lowest delay  modes	 by  disabling	voice-
	       optimized modes.

       cutoff (N.A.)
	   Set cutoff bandwidth	in Hz. The argument must be exactly one	of the
	   following:  4000,  6000,  8000,  12000,  or 20000, corresponding to
	   narrowband, mediumband,  wideband,  super  wideband,	 and  fullband
	   respectively. The default is	0 (cutoff disabled). Note that libopus
	   forces  a  wideband cutoff for bitrates < 15	kbps, unless CELT-only
	   (application	set to lowdelay) mode is used.

       mapping_family (mapping_family)
	   Set channel mapping family to be used by the	encoder.  The  default
	   value  of  -1 uses mapping family 0 for mono	and stereo inputs, and
	   mapping family 1 otherwise. The default also	disables the  surround
	   masking  and	 LFE  bandwidth	 optimzations in libopus, and requires
	   that	the input contains 8 channels or fewer.

	   Other values	include	0 for mono and stereo, 1  for  surround	 sound
	   with	  masking   and	 LFE  bandwidth	 optimizations,	 and  255  for
	   independent streams with an unspecified channel layout.

       apply_phase_inv (N.A.) (requires	libopus	>= 1.2)
	   If set to 0,	disables the use  of  phase  inversion	for  intensity
	   stereo,  improving  the  quality  of	 mono  downmixes, but slightly
	   reducing normal stereo quality. The default is 1  (phase  inversion
	   enabled).

   libshine
       Shine Fixed-Point MP3 encoder wrapper.

       Shine  is a fixed-point MP3 encoder. It has a far better	performance on
       platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
       However,	as it is more targeted on performance than quality, it is  not
       on  par	with  LAME  and	 other production-grade	encoders quality-wise.
       Also, according to the project's	homepage, this encoder may not be free
       of bugs as the code was written a long time ago	and  the  project  was
       dead for	at least 5 years.

       This  encoder  only  supports  stereo and mono input. This is also CBR-
       only.

       The  original  project	(last	updated	  in   early   2007)   is   at
       <http://sourceforge.net/projects/libshine-fxp/>.	 We  only  support the
       updated	  fork	  by	 the	 Savonet/Liquidsoap	project	    at
       <https://github.com/savonet/shine>.

       Requires	 the  presence	of  the	 libshine  headers  and	library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libshine".

       See also	libmp3lame.

       Options

       The  following  options	are  supported	by  the	 libshine wrapper. The
       shineenc-equivalent of the options are listed in	parentheses.

       b (-b)
	   Set bitrate expressed in bits/s for	CBR.  shineenc	-b  option  is
	   expressed in	kilobits/s.

   libtwolame
       TwoLAME MP2 encoder wrapper.

       Requires	 the  presence	of  the	 libtwolame headers and	library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libtwolame".

       Options

       The  following  options	are  supported	by the libtwolame wrapper. The
       twolame-equivalent  options  follow  the	 FFmpeg	 ones	and   are   in
       parentheses.

       b (-b)
	   Set	bitrate	 expressed  in	bits/s	for  CBR.  twolame b option is
	   expressed in	kilobits/s. Default value is 128k.

       q (-V)
	   Set quality for experimental	VBR support. Maximum  value  range  is
	   from	 -50  to  50,  useful  range is	from -10 to 10.	The higher the
	   value, the better the quality. This option is valid only using  the
	   ffmpeg   command-line   tool.  For  library	interface  users,  use
	   global_quality.

       mode (--mode)
	   Set the mode	of the resulting audio.	Possible values:

	   auto
	       Choose mode automatically based	on  the	 input.	 This  is  the
	       default.

	   stereo
	       Stereo

	   joint_stereo
	       Joint stereo

	   dual_channel
	       Dual channel

	   mono
	       Mono

       psymodel	(--psyc-mode)
	   Set	psychoacoustic	model to use in	encoding. The argument must be
	   an integer between -1 and 4,	inclusive. The higher the  value,  the
	   better the quality. The default value is 3.

       energy_levels (--energy)
	   Enable energy levels	extensions when	set to 1. The default value is
	   0 (disabled).

       error_protection	(--protect)
	   Enable  CRC	error protection when set to 1.	The default value is 0
	   (disabled).

       copyright (--copyright)
	   Set MPEG audio copyright flag when set to 1.	The default value is 0
	   (disabled).

       original	(--original)
	   Set MPEG audio original flag	when set to 1. The default value is  0
	   (disabled).

   libvo-amrwbenc
       VisualOn	Adaptive Multi-Rate Wideband encoder.

       Requires	 the presence of the libvo-amrwbenc headers and	library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libvo-amrwbenc	--enable-version3".

       This is a mono-only encoder. Officially it only supports	16000Hz	sample
       rate, but you can override it by	setting	strict to unofficial or	lower.

       Options

       b   Set	bitrate	 in bits/s. Only the following bitrates	are supported,
	   otherwise libavcodec	will round to the nearest valid	bitrate.

	   6600
	   8850
	   12650
	   14250
	   15850
	   18250
	   19850
	   23050
	   23850
       dtx Allow discontinuous transmission (generate comfort noise) when  set
	   to 1. The default value is 0	(disabled).

   libvorbis
       libvorbis encoder wrapper.

       Requires	 the  presence	of the libvorbisenc headers and	library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libvorbis".

       Options

       The  following  options	are  supported	by  the	libvorbis wrapper. The
       oggenc-equivalent of the	options	are listed in parentheses.

       To get a	more accurate and extensive  documentation  of	the  libvorbis
       options,	 consult  the libvorbisenc's and oggenc's documentations.  See
       <http://xiph.org/vorbis/>,   <http://wiki.xiph.org/Vorbis-tools>,   and
       oggenc(1).

       b (-b)
	   Set	bitrate	expressed in bits/s for	ABR. oggenc -b is expressed in
	   kilobits/s.

       q (-q)
	   Set constant	quality	setting	for VBR. The value should be  a	 float
	   number  in  the  range  of  -1.0 to 10.0. The higher	the value, the
	   better the quality. The default value is 3.0.

	   This	option is valid	only using the ffmpeg command-line tool.   For
	   library interface users, use	global_quality.

       cutoff (--advanced-encode-option	lowpass_frequency=N)
	   Set	cutoff bandwidth in Hz,	a value	of 0 disables cutoff. oggenc's
	   related option is expressed in kHz. The default value is 0  (cutoff
	   disabled).

       minrate (-m)
	   Set	minimum	bitrate	expressed in bits/s. oggenc -m is expressed in
	   kilobits/s.

       maxrate (-M)
	   Set maximum bitrate expressed in bits/s. oggenc -M is expressed  in
	   kilobits/s. This only has effect on ABR mode.

       iblock (--advanced-encode-option	impulse_noisetune=N)
	   Set	noise  floor  bias  for	 impulse  blocks. The value is a float
	   number from -15.0 to	0.0. A negative	bias instructs the encoder  to
	   pay special attention to the	crispness of transients	in the encoded
	   audio.  The	tradeoff  for  better  transient  response is a	higher
	   bitrate.

   mjpeg
       Motion JPEG encoder.

       Options

       huffman
	   Set the huffman encoding strategy. Possible values:

	   default
	       Use the default huffman tables. This is the default strategy.

	   optimal
	       Compute and use optimal huffman tables.

   wavpack
       WavPack lossless	audio encoder.

       Options

       The equivalent options for wavpack command line utility are  listed  in
       parentheses.

       Shared options

       The  following  shared  options	are  effective	for this encoder. Only
       special notes about this	particular encoder will	 be  documented	 here.
       For the general meaning of the options, see the Codec Options chapter.

       frame_size (--blocksize)
	   For	this  encoder,	the  range  for	this option is between 128 and
	   131072. Default is automatically decided based on sample  rate  and
	   number of channel.

	   For	  the	complete   formula   of	  calculating	default,   see
	   libavcodec/wavpackenc.c.

       compression_level (-f, -h, -hh, and -x)

       Private options

       joint_stereo (-j)
	   Set whether to enable joint stereo. Valid values are:

	   on (1)
	       Force mid/side audio encoding.

	   off (0)
	       Force left/right	audio encoding.

	   auto
	       Let the encoder decide automatically.

       optimize_mono
	   Set whether to enable optimization for mono.	This  option  is  only
	   effective for non-mono streams. Available values:

	   on  enabled

	   off disabled

VIDEO ENCODERS
       A  description  of  some	 of  the  currently  available	video encoders
       follows.

   a64_multi, a64_multi5
       A64 / Commodore 64 multicolor charset encoder. "a64_multi5" is extended
       with 5th	color (colram).

   Cinepak
       Cinepak aka CVID	encoder.  Compatible  with  Windows  3.1  and  vintage
       MacOS.

       Options

       g integer
	   Keyframe  interval.	 A  keyframe  is  inserted at least every "-g"
	   frames, sometimes sooner.

       q:v integer
	   Quality factor. Lower is better. Higher gives lower	bitrate.   The
	   following  table  lists  bitrates  when  encoding akiyo_cif.y4m for
	   various values of "-q:v" with "-g 100":

	   "-q:v 1" 1918 kb/s
	   "-q:v 2" 1735 kb/s
	   "-q:v 4" 1500 kb/s
	   "-q:v 10" 1041 kb/s
	   "-q:v 20" 826 kb/s
	   "-q:v 40" 553 kb/s
	   "-q:v 100" 394 kb/s
	   "-q:v 200" 312 kb/s
	   "-q:v 400" 266 kb/s
	   "-q:v 1000" 237 kb/s
       max_extra_cb_iterations integer
	   Max extra codebook recalculation passes, more is better and slower.

       skip_empty_cb boolean
	   Avoid wasting bytes,	ignore vintage MacOS decoder.

       max_strips integer
       min_strips integer
	   The minimum and maximum number  of  strips  to  use.	  Wider	 range
	   sometimes  improves	quality.   More	 strips	 is  generally	better
	   quality but costs more bits.	  Fewer	 strips	 tend  to  yield  more
	   keyframes.  Vintage compatible is 1..3.

       strip_number_adaptivity integer
	   How	much  number  of  strips  is allowed to	change between frames.
	   Higher is better but	slower.

   GIF
       GIF image/animation encoder.

       Options

       gifflags	integer
	   Sets	the flags used for GIF encoding.

	   offsetting
	       Enables picture offsetting.

	       Default is enabled.

	   transdiff
	       Enables transparency detection between frames.

	       Default is enabled.

       gifimage	integer
	   Enables encoding one	full GIF  image	 per  frame,  rather  than  an
	   animated GIF.

	   Default value is 0.

       global_palette integer
	   Writes a palette to the global GIF header where feasible.

	   If  disabled,  every	frame will always have a palette written, even
	   if there is a global	palette	supplied.

	   Default value is 1.

   Hap
       Vidvox Hap video	encoder.

       Options

       format integer
	   Specifies the Hap format to encode.

	   hap
	   hap_alpha
	   hap_q

	   Default value is hap.

       chunks integer
	   Specifies the number	of chunks to split frames into,	between	1  and
	   64.	 This	permits	  multithreaded	  decoding  of	large  frames,
	   potentially at the cost of data-rate. The encoder may  modify  this
	   value to divide frames evenly.

	   Default value is 1.

       compressor integer
	   Specifies  the  second-stage	 compressor  to	 use.  If set to none,
	   chunks will be limited to 1,	as chunked uncompressed	 frames	 offer
	   no benefit.

	   none
	   snappy

	   Default value is snappy.

   jpeg2000
       The native jpeg 2000 encoder is lossy by	default, the "-q:v" option can
       be  used	to set the encoding quality. Lossless encoding can be selected
       with "-pred 1".

       Options

       format integer
	   Can be set to either	"j2k" or "jp2" (the  default)  that  makes  it
	   possible to store non-rgb pix_fmts.

       tile_width integer
	   Sets	tile width. Range is 1 to 1073741824. Default is 256.

       tile_height integer
	   Sets	tile height. Range is 1	to 1073741824. Default is 256.

       pred integer
	   Allows setting the discrete wavelet transform (DWT) type

	   dwt97int (Lossy)
	   dwt53 (Lossless)

	   Default is "dwt97int"

       sop boolean
	   Enable this to add SOP marker at the	start of each packet. Disabled
	   by default.

       eph boolean
	   Enable  this	 to  add  EPH marker at	the end	of each	packet header.
	   Disabled by default.

       prog integer
	   Sets	the progression	order to be used  by  the  encoder.   Possible
	   values are:

	   lrcp
	   rlcp
	   rpcl
	   pcrl
	   cprl

	   Set to "lrcp" by default.

       layer_rates string
	   By default, when this option	is not used, compression is done using
	   the	quality	 metric.   This	 option	 allows	 for compression using
	   compression ratio. The compression ratio for	each  level  could  be
	   specified.  The  compression	 ratio of a layer "l" species the what
	   ratio of total file size is contained in the	first "l" layers.

	   Example usage:

		   ffmpeg -i input.bmp -c:v jpeg2000 -layer_rates "100,10,1" output.j2k

	   This	would compress the image to contain 3 layers, where  the  data
	   contained  in  the  first  layer would be compressed	by 1000	times,
	   compressed by 100 in	the first two layers, and  shall  contain  all
	   data	while using all	3 layers.

   librav1e
       rav1e AV1 encoder wrapper.

       Requires	  the  presence	 of  the  rav1e	 headers  and  library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       "--enable-librav1e".

       Options

       qmax
	   Sets	the maximum quantizer to use when using	bitrate	mode.

       qmin
	   Sets	the minimum quantizer to use when using	bitrate	mode.

       qp  Uses	quantizer mode to encode at the	given quantizer	(0-255).

       speed
	   Selects the speed preset (0-10) to encode with.

       tiles
	   Selects how many tiles to encode with.

       tile-rows
	   Selects how many rows of tiles to encode with.

       tile-columns
	   Selects how many columns of tiles to	encode with.

       rav1e-params
	   Set rav1e options using a list of key=value pairs separated by ":".
	   See rav1e --help for	a list of options.

	   For	 example   to	specify	  librav1e   encoding	options	  with
	   -rav1e-params:

		   ffmpeg -i input -c:v	librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4

   libaom-av1
       libaom AV1 encoder wrapper.

       Requires	 the  presence	of  the	 libaom	 headers  and  library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       "--enable-libaom".

       Options

       The wrapper supports the	following standard libavcodec options:

       b   Set bitrate target  in  bits/second.	  By  default  this  will  use
	   variable-bitrate  mode.  If maxrate and minrate are also set	to the
	   same	value then it will use constant-bitrate	mode, otherwise	if crf
	   is set as well then it will use constrained-quality mode.

       g keyint_min
	   Set key frame placement.  The GOP size sets	the  maximum  distance
	   between  key	 frames; if zero the output stream will	be intra-only.
	   The minimum distance	is ignored unless it is	the same  as  the  GOP
	   size,  in  which  case  key	frames	will  always appear at a fixed
	   interval.  Not set by default, so without this option  the  library
	   has completely free choice about where to place key frames.

       qmin qmax
	   Set	minimum/maximum	quantisation values.  Valid range is from 0 to
	   63 (warning:	this does not match the	quantiser values actually used
	   by AV1 - divide by four  to	map  real  quantiser  values  to  this
	   range).  Defaults to	min/max	(no constraint).

       minrate maxrate bufsize rc_init_occupancy
	   Set	rate  control  buffering  parameters.	Not  used if not set -
	   defaults to unconstrained variable bitrate.

       threads
	   Set the number of threads to	use while encoding.  This may  require
	   the	tiles  or  row-mt  options  to also be set to actually use the
	   specified number of	threads	 fully.	 Defaults  to  the  number  of
	   hardware threads supported by the host machine.

       profile
	   Set	the  encoding  profile.	  Defaults  to using the profile which
	   matches the bit depth and chroma subsampling	of the input.

       The wrapper also	has some specific options:

       cpu-used
	   Set the quality/encoding speed tradeoff.  Valid range is from 0  to
	   8,  higher numbers indicating greater speed and lower quality.  The
	   default value is 1, which will be slow and high quality.

       auto-alt-ref
	   Enable use of alternate reference frames.  Defaults to the internal
	   default of the library.

       arnr-max-frames (frames)
	   Set altref noise reduction max frame	count. Default is -1.

       arnr-strength (strength)
	   Set altref noise reduction filter  strength.	 Range	is  -1	to  6.
	   Default is -1.

       aq-mode (aq-mode)
	   Set adaptive	quantization mode. Possible values:

	   none	(0)
	       Disabled.

	   variance (1)
	       Variance-based.

	   complexity (2)
	       Complexity-based.

	   cyclic (3)
	       Cyclic refresh.

       tune (tune)
	   Set	the  distortion	 metric	 the encoder is	tuned with. Default is
	   "psnr".

	   psnr	(0)
	   ssim	(1)
       lag-in-frames
	   Set the maximum number of frames which  the	encoder	 may  keep  in
	   flight  at  any  one	 time for lookahead purposes.  Defaults	to the
	   internal default of the library.

       error-resilience
	   Enable error	resilience features:

	   default
	       Improve resilience against losses of whole frames.

	   Not enabled by default.

       crf Set the quality/size	 tradeoff  for	constant-quality  (no  bitrate
	   target)  and	 constrained-quality  (with  maximum  bitrate  target)
	   modes. Valid	range is 0 to  63,  higher  numbers  indicating	 lower
	   quality and smaller output size.  Only used if set; by default only
	   the bitrate target is used.

       static-thresh
	   Set	a  change threshold on blocks below which they will be skipped
	   by the encoder.   Defined  in  arbitrary  units  as	a  nonnegative
	   integer, defaulting to zero (no blocks are skipped).

       drop-threshold
	   Set	a  threshold  for  dropping  frames when close to rate control
	   bounds.  Defined as a percentage of the target buffer  -  when  the
	   rate	 control  buffer  falls	 below this percentage,	frames will be
	   dropped until it has	refilled above	the  threshold.	  Defaults  to
	   zero	(no frames are dropped).

       denoise-noise-level (level)
	   Amount  of noise to be removed for grain synthesis. Grain synthesis
	   is disabled if this option is not set or set	to 0.

       denoise-block-size (pixels)
	   Block size used for denoising for grain synthesis. If not set,  AV1
	   codec uses the default value	of 32.

       undershoot-pct (pct)
	   Set	datarate  undershoot  (min)  percentage	of the target bitrate.
	   Range is -1 to 100.	Default	is -1.

       overshoot-pct (pct)
	   Set datarate	overshoot (max)	 percentage  of	 the  target  bitrate.
	   Range is -1 to 1000.	 Default is -1.

       minsection-pct (pct)
	   Minimum  percentage	variation  of  the GOP bitrate from the	target
	   bitrate. If	minsection-pct	is  not	 set,  the  libaomenc  wrapper
	   computes  it	 as follows: "(minrate * 100 / bitrate)".  Range is -1
	   to 100. Default is -1 (unset).

       maxsection-pct (pct)
	   Maximum percentage variation	of the GOP  bitrate  from  the	target
	   bitrate.  If	 maxsection-pct	 is  not  set,	the  libaomenc wrapper
	   computes it as follows: "(maxrate * 100 / bitrate)".	 Range	is  -1
	   to 5000. Default is -1 (unset).

       frame-parallel (boolean)
	   Enable frame	parallel decodability features.	Default	is true.

       tiles
	   Set	the number of tiles to encode the input	video with, as columns
	   x rows.  Larger numbers allow greater parallelism in	both  encoding
	   and	decoding, but may decrease coding efficiency.  Defaults	to the
	   minimum number of tiles required by the size	 of  the  input	 video
	   (this is 1x1	(that is, a single tile) for sizes up to and including
	   4K).

       tile-columns tile-rows
	   Set	the  number  of	 tiles	as log2	of the number of tile rows and
	   columns.  Provided for compatibility	with libvpx/VP9.

       row-mt (Requires	libaom >= 1.0.0-759-g90a15f4f2)
	   Enable row based multi-threading. Disabled by default.

       enable-cdef (boolean)
	   Enable Constrained Directional Enhancement Filter.  The  libaom-av1
	   encoder enables CDEF	by default.

       enable-restoration (boolean)
	   Enable Loop Restoration Filter. Default is true for libaom-av1.

       enable-global-motion (boolean)
	   Enable  the	use  of	global motion for block	prediction. Default is
	   true.

       enable-intrabc (boolean)
	   Enable block	copy mode for intra block  prediction.	This  mode  is
	   useful for screen content. Default is true.

       enable-rect-partitions (boolean)	(Requires libaom >= v2.0.0)
	   Enable rectangular partitions. Default is true.

       enable-1to4-partitions (boolean)	(Requires libaom >= v2.0.0)
	   Enable 1:4/4:1 partitions. Default is true.

       enable-ab-partitions (boolean) (Requires	libaom >= v2.0.0)
	   Enable AB shape partitions. Default is true.

       enable-angle-delta (boolean) (Requires libaom >=	v2.0.0)
	   Enable angle	delta intra prediction.	Default	is true.

       enable-cfl-intra	(boolean) (Requires libaom >= v2.0.0)
	   Enable  chroma  predicted  from  luma  intra	prediction. Default is
	   true.

       enable-filter-intra (boolean) (Requires libaom >= v2.0.0)
	   Enable filter intra predictor. Default is true.

       enable-intra-edge-filter	(boolean) (Requires libaom >= v2.0.0)
	   Enable intra	edge filter. Default is	true.

       enable-smooth-intra (boolean) (Requires libaom >= v2.0.0)
	   Enable smooth intra prediction mode.	Default	is true.

       enable-paeth-intra (boolean) (Requires libaom >=	v2.0.0)
	   Enable paeth	predictor in intra prediction. Default is true.

       enable-palette (boolean)	(Requires libaom >= v2.0.0)
	   Enable palette prediction mode. Default is true.

       enable-flip-idtx	(boolean) (Requires libaom >= v2.0.0)
	   Enable   extended   transform   type,    including	 FLIPADST_DCT,
	   DCT_FLIPADST,   FLIPADST_FLIPADST,	ADST_FLIPADST,	FLIPADST_ADST,
	   IDTX, V_DCT,	H_DCT, V_ADST, H_ADST, V_FLIPADST, H_FLIPADST. Default
	   is true.

       enable-tx64 (boolean) (Requires libaom >= v2.0.0)
	   Enable 64-pt	transform. Default is true.

       reduced-tx-type-set (boolean) (Requires libaom >= v2.0.0)
	   Use reduced set of transform	types. Default is false.

       use-intra-dct-only (boolean) (Requires libaom >=	v2.0.0)
	   Use DCT only	for INTRA modes. Default is false.

       use-inter-dct-only (boolean) (Requires libaom >=	v2.0.0)
	   Use DCT only	for INTER modes. Default is false.

       use-intra-default-tx-only (boolean) (Requires libaom >= v2.0.0)
	   Use Default-transform only for INTRA	modes. Default is false.

       enable-ref-frame-mvs (boolean) (Requires	libaom >= v2.0.0)
	   Enable temporal mv prediction. Default is true.

       enable-reduced-reference-set (boolean) (Requires	libaom >= v2.0.0)
	   Use reduced set of  single  and  compound  references.  Default  is
	   false.

       enable-obmc (boolean) (Requires libaom >= v2.0.0)
	   Enable obmc.	Default	is true.

       enable-dual-filter (boolean) (Requires libaom >=	v2.0.0)
	   Enable dual filter. Default is true.

       enable-diff-wtd-comp (boolean) (Requires	libaom >= v2.0.0)
	   Enable difference-weighted compound.	Default	is true.

       enable-dist-wtd-comp (boolean) (Requires	libaom >= v2.0.0)
	   Enable distance-weighted compound. Default is true.

       enable-onesided-comp (boolean) (Requires	libaom >= v2.0.0)
	   Enable one sided compound. Default is true.

       enable-interinter-wedge (boolean) (Requires libaom >= v2.0.0)
	   Enable interinter wedge compound. Default is	true.

       enable-interintra-wedge (boolean) (Requires libaom >= v2.0.0)
	   Enable interintra wedge compound. Default is	true.

       enable-masked-comp (boolean) (Requires libaom >=	v2.0.0)
	   Enable masked compound. Default is true.

       enable-interintra-comp (boolean)	(Requires libaom >= v2.0.0)
	   Enable interintra compound. Default is true.

       enable-smooth-interintra	(boolean) (Requires libaom >= v2.0.0)
	   Enable smooth interintra mode. Default is true.

       aom-params
	   Set	libaom	options	 using	a list of key=value pairs separated by
	   ":".	For a list of supported	options, see aomenc --help  under  the
	   section "AV1	Specific Options".

	   For example to specify libaom encoding options with -aom-params:

		   ffmpeg -i input -c:v	libaom-av1 -b:v	500K -aom-params tune=psnr:enable-tpl-model=1 output.mp4

   libsvtav1
       SVT-AV1 encoder wrapper.

       Requires	 the  presence	of  the	 SVT-AV1  headers  and	library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       "--enable-libsvtav1".

       Options

       profile
	   Set the encoding profile.

	   main
	   high
	   professional
       level
	   Set the operating point level. For example: '4.0'

       hielevel
	   Set the Hierarchical	prediction levels.

	   3level
	   4level
	       This is the default.

       tier
	   Set the operating point tier.

	   main
	       This is the default.

	   high
       qmax
	   Set the maximum quantizer to	use when using a bitrate mode.

       qmin
	   Set the minimum quantizer to	use when using a bitrate mode.

       crf Constant rate factor	value used in crf rate control mode (0-63).

       qp  Set the quantizer used in cqp rate control mode (0-63).

       sc_detection
	   Enable scene	change detection.

       la_depth
	   Set number of frames	to look	ahead (0-120).

       preset
	   Set	the  quality-speed  tradeoff,  in  the	range 0	to 13.	Higher
	   values are faster but lower quality.

       tile_rows
	   Set log2 of the number of rows of tiles to use (0-6).

       tile_columns
	   Set log2 of the number of columns of	tiles to use (0-4).

       svtav1-params
	   Set SVT-AV1 options using a list of key=value  pairs	 separated  by
	   ":".	 See  the  SVT-AV1  encoder  user guide	for a list of accepted
	   parameters.

   libjxl
       libjxl JPEG XL encoder wrapper.

       Requires	 the  presence	of  the	 libjxl	 headers  and  library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       "--enable-libjxl".

       Options

       The libjxl wrapper supports the following options:

       distance
	   Set the target Butteraugli distance.	This  is  a  quality  setting:
	   lower  distance  yields  higher  quality, with distance=1.0 roughly
	   comparable to libjpeg Quality 90 for	photographic content.  Setting
	   distance=0.0	 yields	 true  lossless	 encoding.  Valid values range
	   between 0.0 and 15.0, and sane values rarely	 exceed	 5.0.  Setting
	   distance=0.1	 usually  attains  transparency	 for  most  input. The
	   default is 1.0.

       effort
	   Set the encoding effort used. Higher	 effort	 values	 produce  more
	   consistent quality and usually produces a better quality/bpp	curve,
	   at the cost of more CPU time	required. Valid	values range from 1 to
	   9, and the default is 7.

       modular
	   Force   the	encoder	 to  use  Modular  mode	 instead  of  choosing
	   automatically. The default is to use	VarDCT for lossy encoding  and
	   Modular  for	 lossless. VarDCT is generally superior	to Modular for
	   lossy encoding but does not support lossless	encoding.

   libkvazaar
       Kvazaar H.265/HEVC encoder.

       Requires	the presence of	the  libkvazaar	 headers  and  library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       --enable-libkvazaar.

       Options

       b   Set target video bitrate in bit/s and enable	rate control.

       kvazaar-params
	   Set kvazaar parameters as a list of name=value pairs	 separated  by
	   commas (,). See kvazaar documentation for a list of options.

   libopenh264
       Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.

       This  encoder  requires	the  presence  of  the libopenh264 headers and
       library during configuration. You  need	to  explicitly	configure  the
       build  with  "--enable-libopenh264". The	library	is detected using pkg-
       config.

       For more	information about the library see <http://www.openh264.org>.

       Options

       The following FFmpeg global options affect the  configurations  of  the
       libopenh264 encoder.

       b   Set the bitrate (as a number	of bits	per second).

       g   Set the GOP size.

       maxrate
	   Set the max bitrate (as a number of bits per	second).

       flags +global_header
	   Set global header in	the bitstream.

       slices
	   Set	the  number  of	slices,	used in	parallelized encoding. Default
	   value is 0. This is only used when slice_mode is set	to fixed.

       loopfilter
	   Enable loop filter, if set to 1 (automatically enabled). To disable
	   set a value of 0.

       profile
	   Set profile restrictions. If	set to the value of main enable	 CABAC
	   (set	the "SEncParamExt.iEntropyCodingModeFlag" flag to 1).

       max_nal_size
	   Set maximum NAL size	in bytes.

       allow_skip_frames
	   Allow skipping frames to hit	the target bitrate if set to 1.

   libtheora
       libtheora Theora	encoder	wrapper.

       Requires	 the  presence	of  the	 libtheora  headers and	library	during
       configuration.  You  need  to  explicitly  configure  the  build	  with
       "--enable-libtheora".

       For    more    information    about    the    libtheora	 project   see
       <http://www.theora.org/>.

       Options

       The following global options are	mapped to internal  libtheora  options
       which affect the	quality	and the	bitrate	of the encoded stream.

       b   Set	the  video  bitrate in bit/s for CBR (Constant Bit Rate) mode.
	   In case VBR (Variable Bit Rate) mode	 is  enabled  this  option  is
	   ignored.

       flags
	   Used	 to  enable  constant  quality mode (VBR) encoding through the
	   qscale flag,	and to enable the "pass1" and "pass2" modes.

       g   Set the GOP size.

       global_quality
	   Set the global quality as an	integer	in lambda units.

	   Only	relevant when VBR mode is enabled with	"flags	+qscale".  The
	   value  is  converted	 to QP units by	dividing it by "FF_QP2LAMBDA",
	   clipped in the [0 - 10] range, and then multiplied by 6.3 to	get  a
	   value  in  the  native  libtheora  range  [0-63].  A	 higher	 value
	   corresponds to a higher quality.

       q   Enable VBR mode when	set to a non-negative value, and set  constant
	   quality value as a double floating point value in QP	units.

	   The	value  is  clipped in the [0-10] range,	and then multiplied by
	   6.3 to get a	value in the native libtheora range [0-63].

	   This	option is valid	only using the ffmpeg command-line  tool.  For
	   library interface users, use	global_quality.

       Examples

          Set maximum constant	quality	(VBR) encoding with ffmpeg:

		   ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg

          Use ffmpeg to convert a CBR 1000 kbps Theora	video stream:

		   ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg

   libvpx
       VP8/VP9 format supported	through	libvpx.

       Requires	 the  presence	of  the	 libvpx	 headers  and  library	during
       configuration.	You  need  to  explicitly  configure  the  build  with
       "--enable-libvpx".

       Options

       The  following  options	are  supported	by  the	 libvpx	 wrapper.  The
       vpxenc-equivalent options or values are listed in parentheses for  easy
       migration.

       To  reduce  the	duplication of documentation, only the private options
       and some	others requiring special attention are	documented  here.  For
       the  documentation  of  the undocumented	generic	options, see the Codec
       Options chapter.

       To get more documentation of the	libvpx	options,  invoke  the  command
       ffmpeg  -h  encoder=libvpx,  ffmpeg  -h	encoder=libvpx-vp9  or	vpxenc
       --help.	Further	 information  is   available   in   the	  libvpx   API
       documentation.

       b (target-bitrate)
	   Set	bitrate	in bits/s. Note	that FFmpeg's b	option is expressed in
	   bits/s, while vpxenc's target-bitrate is in kilobits/s.

       g (kf-max-dist)
       keyint_min (kf-min-dist)
       qmin (min-q)
	   Minimum (Best Quality) Quantizer.

       qmax (max-q)
	   Maximum (Worst Quality) Quantizer.  Can be changed per-frame.

       bufsize (buf-sz,	buf-optimal-sz)
	   Set ratecontrol buffer size (in bits). Note	vpxenc's  options  are
	   specified  in  milliseconds,	the libvpx wrapper converts this value
	   as follows: "buf-sz = bufsize * 1000	/ bitrate", "buf-optimal-sz  =
	   bufsize * 1000 / bitrate * 5	/ 6".

       rc_init_occupancy (buf-initial-sz)
	   Set number of bits which should be loaded into the rc buffer	before
	   decoding starts. Note vpxenc's option is specified in milliseconds,
	   the	  libvpx    wrapper    converts	  this	 value	 as   follows:
	   "rc_init_occupancy *	1000 / bitrate".

       undershoot-pct
	   Set datarate	undershoot (min) percentage of the target bitrate.

       overshoot-pct
	   Set datarate	overshoot (max)	percentage of the target bitrate.

       skip_threshold (drop-frame)
       qcomp (bias-pct)
       maxrate (maxsection-pct)
	   Set GOP max bitrate in bits/s. Note vpxenc's	option is specified as
	   a percentage	of the target bitrate,	the  libvpx  wrapper  converts
	   this	value as follows: "(maxrate * 100 / bitrate)".

       minrate (minsection-pct)
	   Set GOP min bitrate in bits/s. Note vpxenc's	option is specified as
	   a  percentage  of  the  target bitrate, the libvpx wrapper converts
	   this	value as follows: "(minrate * 100 / bitrate)".

       minrate,	maxrate, b end-usage=cbr
	   "(minrate ==	maxrate	== bitrate)".

       crf (end-usage=cq, cq-level)
       tune (tune)
	   psnr	(psnr)
	   ssim	(ssim)
       quality,	deadline (deadline)
	   best
	       Use best	quality	deadline. Poorly named and  quite  slow,  this
	       option  should  be  avoided as it may give worse	quality	output
	       than good.

	   good
	       Use good	quality	deadline. This is  a  good  trade-off  between
	       speed and quality when used with	the cpu-used option.

	   realtime
	       Use realtime quality deadline.

       speed, cpu-used (cpu-used)
	   Set quality/speed ratio modifier. Higher values speed up the	encode
	   at the cost of quality.

       nr (noise-sensitivity)
       static-thresh
	   Set	a  change threshold on blocks below which they will be skipped
	   by the encoder.

       slices (token-parts)
	   Note	 that  FFmpeg's	 slices	 option	 gives	the  total  number  of
	   partitions,	  while	   vpxenc's    token-parts    is    given   as
	   "log2(partitions)".

       max-intra-rate
	   Set maximum I-frame bitrate as a percentage of the target  bitrate.
	   A value of 0	means unlimited.

       force_key_frames
	   "VPX_EFLAG_FORCE_KF"

       Alternate reference frame related
	   auto-alt-ref
	       Enable use of alternate reference frames	(2-pass	only).	Values
	       greater	than  1	 enable	multi-layer alternate reference	frames
	       (VP9 only).

	   arnr-maxframes
	       Set altref noise	reduction max frame count.

	   arnr-type
	       Set altref noise	 reduction  filter  type:  backward,  forward,
	       centered.

	   arnr-strength
	       Set altref noise	reduction filter strength.

	   rc-lookahead, lag-in-frames (lag-in-frames)
	       Set   number   of  frames  to  look  ahead  for	frametype  and
	       ratecontrol.

	   min-gf-interval
	       Set minimum  golden/alternate  reference	 frame	interval  (VP9
	       only).

       error-resilient
	   Enable error	resiliency features.

       sharpness integer
	   Increase  sharpness	at the expense of lower	PSNR.  The valid range
	   is [0, 7].

       ts-parameters
	   Sets	the temporal scalability  configuration	 using	a  :-separated
	   list	  of   key=value  pairs.  For  example,	 to  specify  temporal
	   scalability parameters with "ffmpeg":

		   ffmpeg -i INPUT -c:v	libvpx -ts-parameters ts_number_layers=3:\
		   ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\
		   ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT

	   Below is a brief explanation	of  each  of  the  parameters,	please
	   refer to "struct vpx_codec_enc_cfg" in "vpx/vpx_encoder.h" for more
	   details.

	   ts_number_layers
	       Number of temporal coding layers.

	   ts_target_bitrate
	       Target  bitrate	for  each  temporal layer (in kbps).  (bitrate
	       should be inclusive of the lower	temporal layer).

	   ts_rate_decimator
	       Frame rate decimation factor for	each temporal layer.

	   ts_periodicity
	       Length  of  the	sequence   defining   frame   temporal	 layer
	       membership.

	   ts_layer_id
	       Template	defining the membership	of frames to temporal layers.

	   ts_layering_mode
	       (optional)  Selecting the temporal structure from a set of pre-
	       defined	temporal  layering  modes.   Currently	supports   the
	       following options.

	       0   No  temporal	layering flags are provided internally,	relies
		   on  flags  being  passed  in	 using	"metadata"  field   in
		   "AVFrame" with following keys.

		   vp8-flags
		       Sets  the flags passed into the encoder to indicate the
		       referencing scheme for the  current  frame.   Refer  to
		       function	 "vpx_codec_encode" in "vpx/vpx_encoder.h" for
		       more details.

		   temporal_id
		       Explicitly sets the temporal id of the current frame to
		       encode.

	       2   Two temporal	layers.	0-1...

	       3   Three temporal layers. 0-2-1-2...;  with  single  reference
		   frame.

	       4   Same	 as  option  "3", except there is a dependency between
		   the two temporal layer 2 frames within the temporal period.

       VP9-specific options
	   lossless
	       Enable lossless mode.

	   tile-columns
	       Set number of tile columns  to  use.  Note  this	 is  given  as
	       "log2(tile_columns)".  For  example,  8	tile  columns would be
	       requested by setting the	tile-columns option to 3.

	   tile-rows
	       Set number  of  tile  rows  to  use.  Note  this	 is  given  as
	       "log2(tile_rows)".  For example,	4 tile rows would be requested
	       by setting the tile-rows	option to 2.

	   frame-parallel
	       Enable frame parallel decodability features.

	   aq-mode
	       Set  adaptive  quantization mode	(0: off	(default), 1: variance
	       2: complexity, 3: cyclic	refresh, 4: equator360).

	   colorspace color-space
	       Set input color space. The VP9 bitstream	supports signaling the
	       following colorspaces:

	       rgb sRGB
	       bt709 bt709
	       unspecified unknown
	       bt470bg bt601
	       smpte170m smpte170
	       smpte240m smpte240
	       bt2020_ncl bt2020
	   row-mt boolean
	       Enable row based	multi-threading.

	   tune-content
	       Set content type: default (0), screen (1), film (2).

	   corpus-complexity
	       Corpus VBR  mode	 is  a	variant	 of  standard  VBR  where  the
	       complexity  distribution	 midpoint  is  passed  in  rather than
	       calculated for a	specific clip or chunk.

	       The valid range is [0, 10000]. 0	(default) uses standard	VBR.

	   enable-tpl boolean
	       Enable temporal dependency model.

	   ref-frame-config
	       Using  per-frame	 metadata,  set	 members  of   the   structure
	       "vpx_svc_ref_frame_config_t"  in	 "vpx/vp8cx.h" to fine-control
	       referencing  schemes  and  frame	 buffer	 management.   Use   a
	       :-separated list	of key=value pairs.  For example,

		       av_dict_set(&av_frame->metadata,	"ref-frame-config", \
		       "rfc_update_buffer_slot=7:rfc_lst_fb_idx=0:rfc_gld_fb_idx=1:rfc_alt_fb_idx=2:rfc_reference_last=0:rfc_reference_golden=0:rfc_reference_alt_ref=0");

	       rfc_update_buffer_slot
		   Indicates the buffer	slot number to update

	       rfc_update_last
		   Indicates whether to	update the LAST	frame

	       rfc_update_golden
		   Indicates whether to	update GOLDEN frame

	       rfc_update_alt_ref
		   Indicates whether to	update ALT_REF frame

	       rfc_lst_fb_idx
		   LAST	frame buffer index

	       rfc_gld_fb_idx
		   GOLDEN frame	buffer index

	       rfc_alt_fb_idx
		   ALT_REF frame buffer	index

	       rfc_reference_last
		   Indicates whether to	reference LAST frame

	       rfc_reference_golden
		   Indicates whether to	reference GOLDEN frame

	       rfc_reference_alt_ref
		   Indicates whether to	reference ALT_REF frame

	       rfc_reference_duration
		   Indicates frame duration

       For more	information about libvpx see: <http://www.webmproject.org/>

   libwebp
       libwebp WebP Image encoder wrapper

       libwebp	is Google's official encoder for WebP images. It can encode in
       either lossy or lossless	mode. Lossy images are essentially  a  wrapper
       around  a  VP8 frame. Lossless images are a separate codec developed by
       Google.

       Pixel Format

       Currently, libwebp only supports	YUV420 for lossy and RGB for  lossless
       due  to	limitations  of	the format and libwebp.	Alpha is supported for
       either mode.  Because of	API limitations, if  RGB  is  passed  in  when
       encoding	 lossy	or  YUV	 is passed in for encoding lossless, the pixel
       format will automatically be converted using  functions	from  libwebp.
       This is not ideal and is	done only for convenience.

       Options

       -lossless boolean
	   Enables/Disables use	of lossless mode. Default is 0.

       -compression_level integer
	   For	lossy,	this  is  a quality/speed tradeoff. Higher values give
	   better quality for a	given size at the cost of  increased  encoding
	   time.  For  lossless,  this is a size/speed tradeoff. Higher	values
	   give	smaller	size at	the cost  of  increased	 encoding  time.  More
	   specifically,  it  controls	the  number  of	 extra	algorithms and
	   compression tools used, and varies the combination of these	tools.
	   This	 maps to the method option in libwebp. The valid range is 0 to
	   6.  Default is 4.

       -quality	float
	   For lossy encoding,	this  controls	image  quality.	 For  lossless
	   encoding,  this  controls the effort	and time spent in compression.
	   Range is 0 to 100. Default is 75.

       -preset type
	   Configuration preset. This does some	automatic  settings  based  on
	   the general type of the image.

	   none
	       Do not use a preset.

	   default
	       Use the encoder default.

	   picture
	       Digital picture,	like portrait, inner shot

	   photo
	       Outdoor photograph, with	natural	lighting

	   drawing
	       Hand or line drawing, with high-contrast	details

	   icon
	       Small-sized colorful images

	   text
	       Text-like

   libx264, libx264rgb
       x264 H.264/MPEG-4 AVC encoder wrapper.

       This  encoder  requires the presence of the libx264 headers and library
       during configuration. You need to explicitly configure the  build  with
       "--enable-libx264".

       libx264	supports  an  impressive number	of features, including 8x8 and
       4x4 adaptive spatial transform, adaptive	B-frame	placement, CAVLC/CABAC
       entropy coding, interlacing (MBAFF), lossless mode,  psy	 optimizations
       for detail retention (adaptive quantization, psy-RD, psy-trellis).

       Many libx264 encoder options are	mapped to FFmpeg global	codec options,
       while  unique  encoder  options	are  provided through private options.
       Additionally the	x264opts and x264-params private options allows	one to
       pass  a	list  of  key=value  tuples  as	 accepted   by	 the   libx264
       "x264_param_parse" function.

       The	    x264	 project	 website	 is	    at
       <http://www.videolan.org/developers/x264.html>.

       The libx264rgb encoder is the same as libx264, except it	accepts	packed
       RGB pixel formats as input instead of YUV.

       Supported Pixel Formats

       x264 supports 8-	to  10-bit  color  spaces.  The	 exact	bit  depth  is
       controlled at x264's configure time.

       Options

       The  following  options	are  supported	by  the	 libx264  wrapper. The
       x264-equivalent options or values are listed in	parentheses  for  easy
       migration.

       To  reduce  the	duplication of documentation, only the private options
       and some	others requiring special attention are	documented  here.  For
       the  documentation  of  the undocumented	generic	options, see the Codec
       Options chapter.

       To get a	more accurate  and  extensive  documentation  of  the  libx264
       options,	 invoke	 the  command  x264  --fullhelp	or consult the libx264
       documentation.

       b (bitrate)
	   Set bitrate in bits/s. Note that FFmpeg's b option is expressed  in
	   bits/s, while x264's	bitrate	is in kilobits/s.

       bf (bframes)
       g (keyint)
       qmin (qpmin)
	   Minimum quantizer scale.

       qmax (qpmax)
	   Maximum quantizer scale.

       qdiff (qpstep)
	   Maximum difference between quantizer	scales.

       qblur (qblur)
	   Quantizer curve blur

       qcomp (qcomp)
	   Quantizer curve compression factor

       refs (ref)
	   Number  of reference	frames each P-frame can	use. The range is from
	   0-16.

       level (level)
	   Set the "x264_param_t.i_level_idc"  value  in  case	the  value  is
	   positive, it	is ignored otherwise.

	   This	 value	can  be	 set  using  the "AVCodecContext" API (e.g. by
	   setting the "AVCodecContext"	value directly), and is	 specified  as
	   an  integer mapped on a corresponding level (e.g. the value 31 maps
	   to H.264 level IDC "3.1", as	defined	in the	"x264_levels"  table).
	   It is ignored when set to a non positive value.

	   Alternatively  it  can  be  set as a	private	option,	overriding the
	   value set in	"AVCodecContext", and in this case must	 be  specified
	   as the level	IDC identifier (e.g. "3.1"), as	defined	by H.264 Annex
	   A.

       sc_threshold (scenecut)
	   Sets	the threshold for the scene change detection.

       trellis (trellis)
	   Performs  Trellis  quantization  to increase	efficiency. Enabled by
	   default.

       nr  (nr)
       me_range	(merange)
	   Maximum range of the	motion search in pixels.

       me_method (me)
	   Set motion estimation method. Possible  values  in  the  decreasing
	   order of speed:

	   dia (dia)
	   epzs	(dia)
	       Diamond	search	with  radius 1 (fastest). epzs is an alias for
	       dia.

	   hex (hex)
	       Hexagonal search	with radius 2.

	   umh (umh)
	       Uneven multi-hexagon search.

	   esa (esa)
	       Exhaustive search.

	   tesa	(tesa)
	       Hadamard	exhaustive search (slowest).

       forced-idr
	   Normally, when forcing a I-frame type, the encoder can  select  any
	   type	of I-frame. This option	forces it to choose an IDR-frame.

       subq (subme)
	   Sub-pixel motion estimation method.

       b_strategy (b-adapt)
	   Adaptive  B-frame  placement	decision algorithm. Use	only on	first-
	   pass.

       keyint_min (min-keyint)
	   Minimum GOP size.

       coder
	   Set entropy encoder.	Possible values:

	   ac  Enable CABAC.

	   vlc Enable CAVLC and	disable	CABAC. It generates the	same effect as
	       x264's --no-cabac option.

       cmp Set full pixel motion  estimation  comparison  algorithm.  Possible
	   values:

	   chroma
	       Enable chroma in	motion estimation.

	   sad Ignore  chroma  in  motion  estimation.	It  generates the same
	       effect as x264's	--no-chroma-me option.

       threads (threads)
	   Number of encoding threads.

       thread_type
	   Set multithreading technique. Possible values:

	   slice
	       Slice-based multithreading. It generates	 the  same  effect  as
	       x264's --sliced-threads option.

	   frame
	       Frame-based multithreading.

       flags
	   Set encoding	flags. It can be used to disable closed	GOP and	enable
	   open	 GOP  by  setting  it to "-cgop". The result is	similar	to the
	   behavior of x264's --open-gop option.

       rc_init_occupancy (vbv-init)
       preset (preset)
	   Set the encoding preset.

       tune (tune)
	   Set tuning of the encoding params.

       profile (profile)
	   Set profile restrictions.

       fastfirstpass
	   Enable fast settings	when encoding first pass, when set to 1.  When
	   set to 0, it	has the	same effect of x264's --slow-firstpass option.

       crf (crf)
	   Set the quality for constant	quality	mode.

       crf_max (crf-max)
	   In CRF mode,	prevents VBV from lowering quality beyond this point.

       qp (qp)
	   Set constant	quantization rate control method parameter.

       aq-mode (aq-mode)
	   Set AQ method. Possible values:

	   none	(0)
	       Disabled.

	   variance (1)
	       Variance	AQ (complexity mask).

	   autovariance	(2)
	       Auto-variance AQ	(experimental).

       aq-strength (aq-strength)
	   Set	AQ strength, reduce blocking and blurring in flat and textured
	   areas.

       psy Use psychovisual optimizations when set to 1. When set to 0,	it has
	   the same effect as x264's --no-psy option.

       psy-rd  (psy-rd)
	   Set strength	of psychovisual	 optimization,	in  psy-rd:psy-trellis
	   format.

       rc-lookahead (rc-lookahead)
	   Set number of frames	to look	ahead for frametype and	ratecontrol.

       weightb
	   Enable  weighted prediction for B-frames when set to	1. When	set to
	   0, it has the same effect as	x264's --no-weightb option.

       weightp (weightp)
	   Set weighted	prediction method for P-frames.	Possible values:

	   none	(0)
	       Disabled

	   simple (1)
	       Enable only weighted refs

	   smart (2)
	       Enable both weighted refs and duplicates

       ssim (ssim)
	   Enable calculation and printing SSIM	stats after the	encoding.

       intra-refresh (intra-refresh)
	   Enable the use of Periodic Intra Refresh instead of IDR frames when
	   set to 1.

       avcintra-class (class)
	   Configure the encoder to  generate  AVC-Intra.   Valid  values  are
	   50,100 and 200

       bluray-compat (bluray-compat)
	   Configure  the  encoder  to be compatible with the bluray standard.
	   It is a shorthand for setting "bluray-compat=1 force-cfr=1".

       b-bias (b-bias)
	   Set the influence on	how often B-frames are used.

       b-pyramid (b-pyramid)
	   Set method for keeping of some  B-frames  as	 references.  Possible
	   values:

	   none	(none)
	       Disabled.

	   strict (strict)
	       Strictly	hierarchical pyramid.

	   normal (normal)
	       Non-strict (not Blu-ray compatible).

       mixed-refs
	   Enable  the	use  of	one reference per partition, as	opposed	to one
	   reference per macroblock when set to	1. When	set to 0, it  has  the
	   same	effect as x264's --no-mixed-refs option.

       8x8dct
	   Enable adaptive spatial transform (high profile 8x8 transform) when
	   set	to  1.	When  set  to  0,  it  has  the	 same effect as	x264's
	   --no-8x8dct option.

       fast-pskip
	   Enable early	SKIP detection on P-frames when	set to 1. When set  to
	   0, it has the same effect as	x264's --no-fast-pskip option.

       aud (aud)
	   Enable use of access	unit delimiters	when set to 1.

       mbtree
	   Enable  use	macroblock tree	ratecontrol when set to	1. When	set to
	   0, it has the same effect as	x264's --no-mbtree option.

       deblock (deblock)
	   Set loop filter parameters, in alpha:beta form.

       cplxblur	(cplxblur)
	   Set fluctuations reduction in QP (before curve compression).

       partitions (partitions)
	   Set partitions to consider as a comma-separated list	 of.  Possible
	   values in the list:

	   p8x8
	       8x8 P-frame partition.

	   p4x4
	       4x4 P-frame partition.

	   b8x8
	       4x4 B-frame partition.

	   i8x8
	       8x8 I-frame partition.

	   i4x4
	       4x4  I-frame  partition.	  (Enabling  p4x4  requires p8x8 to be
	       enabled.	Enabling  i8x8	requires  adaptive  spatial  transform
	       (8x8dct option) to be enabled.)

	   none	(none)
	       Do not consider any partitions.

	   all (all)
	       Consider	every partition.

       direct-pred (direct)
	   Set direct MV prediction mode. Possible values:

	   none	(none)
	       Disable MV prediction.

	   spatial (spatial)
	       Enable spatial predicting.

	   temporal (temporal)
	       Enable temporal predicting.

	   auto	(auto)
	       Automatically decided.

       slice-max-size (slice-max-size)
	   Set	the limit of the size of each slice in bytes. If not specified
	   but RTP payload size	(ps) is	specified, that	is used.

       stats (stats)
	   Set the file	name for multi-pass stats.

       nal-hrd (nal-hrd)
	   Set signal  HRD  information	 (requires  vbv-bufsize	 to  be	 set).
	   Possible values:

	   none	(none)
	       Disable HRD information signaling.

	   vbr (vbr)
	       Variable	bit rate.

	   cbr (cbr)
	       Constant	bit rate (not allowed in MP4 container).

       x264opts	(N.A.)
	   Set any x264	option,	see x264 --fullhelp for	a list.

	   Argument is a list of key=value couples separated by	":". In	filter
	   and	psy-rd options that use	":" as a separator themselves, use ","
	   instead. They accept	it as well since long ago  but	this  is  kept
	   undocumented	for some reason.

	   For example to specify libx264 encoding options with	ffmpeg:

		   ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv

       a53cc boolean
	   Import  closed captions (which must be ATSC compatible format) into
	   output.  Only the mpeg2 and h264 decoders provide these. Default is
	   1 (on).

       udu_sei boolean
	   Import user data unregistered SEI if	available into output. Default
	   is 0	(off).

       mb_info boolean
	   Set mb_info data through AVFrameSideData,  only  useful  when  used
	   from	the API. Default is 0 (off).

       x264-params (N.A.)
	   Override  the  x264	configuration  using  a	 :-separated  list  of
	   key=value parameters.

	   This	option is functionally	the  same  as  the  x264opts,  but  is
	   duplicated for compatibility	with the Libav fork.

	   For example to specify libx264 encoding options with	ffmpeg:

		   ffmpeg -i INPUT -c:v	libx264	-x264-params level=30:bframes=0:weightp=0:\
		   cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
		   no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT

       Encoding	 ffpresets  for	common usages are provided so they can be used
       with the	general	presets	system (e.g. passing the pre option).

   libx265
       x265 H.265/HEVC encoder wrapper.

       This encoder requires the presence of the libx265 headers  and  library
       during  configuration.  You need	to explicitly configure	the build with
       --enable-libx265.

       Options

       b   Sets	target video bitrate.

       bf
       g   Set the GOP size.

       keyint_min
	   Minimum GOP size.

       refs
	   Number of reference frames each P-frame can use. The	range is  from
	   1-16.

       preset
	   Set the x265	preset.

       tune
	   Set the x265	tune parameter.

       profile
	   Set profile restrictions.

       crf Set the quality for constant	quality	mode.

       qp  Set constant	quantization rate control method parameter.

       qmin
	   Minimum quantizer scale.

       qmax
	   Maximum quantizer scale.

       qdiff
	   Maximum difference between quantizer	scales.

       qblur
	   Quantizer curve blur

       qcomp
	   Quantizer curve compression factor

       i_qfactor
       b_qfactor
       forced-idr
	   Normally,  when  forcing a I-frame type, the	encoder	can select any
	   type	of I-frame. This option	forces it to choose an IDR-frame.

       udu_sei boolean
	   Import user data unregistered SEI if	available into output. Default
	   is 0	(off).

       x265-params
	   Set x265 options using a list of  key=value	couples	 separated  by
	   ":".	See x265 --help	for a list of options.

	   For example to specify libx265 encoding options with	-x265-params:

		   ffmpeg -i input -c:v	libx265	-x265-params crf=26:psy-rd=1 output.mp4

   libxavs2
       xavs2 AVS2-P2/IEEE1857.4	encoder	wrapper.

       This  encoder requires the presence of the libxavs2 headers and library
       during configuration. You need to explicitly configure the  build  with
       --enable-libxavs2.

       The following standard libavcodec options are used:

          b / bit_rate

          g / gop_size

          bf /	max_b_frames

       The encoder also	has its	own specific options:

       Options

       lcu_row_threads
	   Set	the  number  of	parallel threads for rows from 1 to 8 (default
	   5).

       initial_qp
	   Set the xavs2 quantization parameter	from 1	to  63	(default  34).
	   This	is used	to set the initial qp for the first frame.

       qp  Set	the  xavs2  quantization  parameter from 1 to 63 (default 34).
	   This	is used	to set the qp value under constant-QP mode.

       max_qp
	   Set the max qp for rate control from	1 to 63	(default 55).

       min_qp
	   Set the min qp for rate control from	1 to 63	(default 20).

       speed_level
	   Set the Speed level from 0 to 9 (default 0).	Higher is  better  but
	   slower.

       log_level
	   Set	the log	level from -1 to 3 (default 0).	-1: none, 0: error, 1:
	   warning, 2: info, 3:	debug.

       xavs2-params
	   Set xavs2 options using a list of key=value	couples	 separated  by
	   ":".

	   For	 example   to	specify	  libxavs2   encoding	options	  with
	   -xavs2-params:

		   ffmpeg -i input -c:v	libxavs2 -xavs2-params RdoqLevel=0 output.avs2

   libxvid
       Xvid MPEG-4 Part	2 encoder wrapper.

       This encoder requires the  presence  of	the  libxvidcore  headers  and
       library	during	configuration.	You  need  to explicitly configure the
       build with "--enable-libxvid --enable-gpl".

       The native "mpeg4" encoder supports the MPEG-4 Part 2 format, so	 users
       can encode to this format without this library.

       Options

       The following options are supported by the libxvid wrapper. Some	of the
       following  options are listed but are not documented, and correspond to
       shared  codec  options.	See  the  Codec	 Options  chapter  for	 their
       documentation.  The  other  shared options which	are not	listed have no
       effect for the libxvid encoder.

       b
       g
       qmin
       qmax
       mpeg_quant
       threads
       bf
       b_qfactor
       b_qoffset
       flags
	   Set specific	encoding flags.	Possible values:

	   mv4 Use four	motion vector by macroblock.

	   aic Enable high quality AC prediction.

	   gray
	       Only encode grayscale.

	   gmc Enable the use of global	motion compensation (GMC).

	   qpel
	       Enable quarter-pixel motion compensation.

	   cgop
	       Enable closed GOP.

	   global_header
	       Place global headers in extradata instead of every keyframe.

       trellis
       me_quality
	   Set motion estimation quality level.	Possible values	in  decreasing
	   order of speed and increasing order of quality:

	   0   Use no motion estimation	(default).

	   1, 2
	       Enable advanced diamond zonal search for	16x16 blocks and half-
	       pixel refinement	for 16x16 blocks.

	   3, 4
	       Enable all of the things	described above, plus advanced diamond
	       zonal  search  for 8x8 blocks and half-pixel refinement for 8x8
	       blocks, also enable motion estimation on	chroma	planes	for  P
	       and B-frames.

	   5, 6
	       Enable  all  of the things described above, plus	extended 16x16
	       and 8x8 blocks search.

       mbd Set	macroblock  decision  algorithm.  Possible   values   in   the
	   increasing order of quality:

	   simple
	       Use macroblock comparing	function algorithm (default).

	   bits
	       Enable  rate  distortion-based  half  pixel  and	 quarter pixel
	       refinement for 16x16 blocks.

	   rd  Enable all of the things	described above, plus rate distortion-
	       based half pixel	and quarter pixel refinement for  8x8  blocks,
	       and rate	distortion-based search	using square pattern.

       lumi_aq
	   Enable lumi masking adaptive	quantization when set to 1. Default is
	   0 (disabled).

       variance_aq
	   Enable  variance  adaptive quantization when	set to 1. Default is 0
	   (disabled).

	   When	combined with lumi_aq,	the  resulting	quality	 will  not  be
	   better  than	any of the two specified individually. In other	words,
	   the resulting quality will be the worse one of the two effects.

       ssim
	   Set	structural  similarity	(SSIM)	displaying  method.   Possible
	   values:

	   off Disable displaying of SSIM information.

	   avg Output  average	SSIM  at  the  end  of encoding	to stdout. The
	       format of showing the average SSIM is:

		       Average SSIM: %f

	       For users who are not familiar with C, %f means a float number,
	       or a decimal (e.g. 0.939232).

	   frame
	       Output both per-frame SSIM data	during	encoding  and  average
	       SSIM  at	the end	of encoding to stdout. The format of per-frame
	       information is:

			      SSIM: avg: %1.3f min: %1.3f max: %1.3f

	       For users who are not familiar with  C,	%1.3f  means  a	 float
	       number rounded to 3 digits after	the dot	(e.g. 0.932).

       ssim_acc
	   Set	SSIM  accuracy.	Valid options are integers within the range of
	   0-4,	while 0	gives the most accurate	 result	 and  4	 computes  the
	   fastest.

   MediaFoundation
       This  provides  wrappers	 to  encoders  (both  audio  and video)	in the
       MediaFoundation framework. It can  access  both	SW  and	 HW  encoders.
       Video  encoders	can take input in either of nv12 or yuv420p form (some
       encoders	support	both, some support only	either - in practice, nv12  is
       the safer choice, especially among HW encoders).

   Microsoft RLE
       Microsoft  RLE  aka  MSRLE encoder.  Only 8-bit palette mode supported.
       Compatible with Windows 3.1 and Windows 95.

       Options

       g integer
	   Keyframe interval.  A keyframe is  inserted	at  least  every  "-g"
	   frames, sometimes sooner.

   mpeg2
       MPEG-2 video encoder.

       Options

       profile
	   Select the mpeg2 profile to encode:

	   422
	   high
	   ss  Spatially Scalable

	   snr SNR Scalable

	   main
	   simple
       level
	   Select the mpeg2 level to encode:

	   high
	   high1440
	   main
	   low
       seq_disp_ext integer
	   Specifies  if the encoder should write a sequence_display_extension
	   to the output.

	   -1
	   auto
	       Decide automatically to write it	or not (this is	 the  default)
	       by  checking  if	 the  data to be written is different from the
	       default or unspecified values.

	   0
	   never
	       Never write it.

	   1
	   always
	       Always write it.

       video_format integer
	   Specifies  the  video_format	 written  into	the  sequence  display
	   extension  indicating the source of the video pictures. The default
	   is unspecified, can be component, pal, ntsc,	 secam	or  mac.   For
	   maximum compatibility, use component.

       a53cc boolean
	   Import  closed captions (which must be ATSC compatible format) into
	   output.  Default is 1 (on).

   png
       PNG image encoder.

       Private options

       dpi integer
	   Set physical	density	of pixels, in dots per inch, unset by default

       dpm integer
	   Set physical	density	of pixels, in dots per meter, unset by default

   ProRes
       Apple ProRes encoder.

       FFmpeg contains 2 ProRes	encoders, the prores-aw	and prores-ks encoder.
       The used	encoder	can be chosen with the "-vcodec" option.

       Private Options for prores-ks

       profile integer
	   Select the ProRes profile to	encode

	   proxy
	   lt
	   standard
	   hq
	   4444
	   4444xq
       quant_mat integer
	   Select quantization matrix.

	   auto
	   default
	   proxy
	   lt
	   standard
	   hq

	   If set to auto, the matrix matching the profile will	be picked.  If
	   not set, the	matrix providing the highest quality, default, will be
	   picked.

       bits_per_mb integer
	   How many  bits  to  allot  for  coding  one	macroblock.  Different
	   profiles  use between 200 and 2400 bits per macroblock, the maximum
	   is 8000.

       mbs_per_slice integer
	   Number of macroblocks in each slice (1-8); the  default  value  (8)
	   should be good in almost all	situations.

       vendor string
	   Override  the 4-byte	vendor ID.  A custom vendor ID like apl0 would
	   claim the stream was	produced by the	Apple encoder.

       alpha_bits integer
	   Specify number of bits for alpha component.	Possible values	are 0,
	   8 and 16.  Use 0 to disable alpha plane coding.

       Speed considerations

       In the default mode  of	operation  the	encoder	 has  to  honor	 frame
       constraints  (i.e.  not produce frames with size	bigger than requested)
       while still making  output  picture  as	good  as  possible.   A	 frame
       containing a lot	of small details is harder to compress and the encoder
       would  spend  more  time	 searching for appropriate quantizers for each
       slice.

       Setting a higher	bits_per_mb limit will improve the speed.

       For the fastest encoding	speed set  the	qscale	parameter  (4  is  the
       recommended value) and do not set a size	constraint.

   QSV Encoders
       The  family  of	Intel  QuickSync  Video	encoders (MPEG-2, H.264, HEVC,
       JPEG/MJPEG, VP9,	AV1)

       Ratecontrol Method

       The ratecontrol method is selected as follows:

          When	global_quality is specified, a	quality-based  mode  is	 used.
	   Specifically	this means either

	   -   CQP  -  constant	quantizer scale, when the qscale codec flag is
	       also set	(the -qscale ffmpeg option).

	   -   LA_ICQ -	intelligent constant quality with lookahead, when  the
	       look_ahead option is also set.

	   -   ICQ  --	intelligent  constant  quality	otherwise. For the ICQ
	       modes, global quality range is 1	to 51, with 1 being  the  best
	       quality.

          Otherwise,  a  bitrate-based	 mode  is  used. For all of those, you
	   should specify at least the desired	average	 bitrate  with	the  b
	   option.

	   -   LA  -  VBR  with	 lookahead,  when  the	look_ahead  option  is
	       specified.

	   -   VCM - video conferencing	mode, when the vcm option is set.

	   -   CBR - constant bitrate, when maxrate is specified and equal  to
	       the average bitrate.

	   -   VBR  -  variable	 bitrate,  when	 maxrate  is specified,	but is
	       higher than the average bitrate.

	   -   AVBR - average VBR mode,	when maxrate is	 not  specified,  both
	       avbr_accuracy  and  avbr_convergence  are set to	non-zero. This
	       mode is available for H264 and HEVC on Windows.

       Note that depending on your system, a different mode than the  one  you
       specified  may  be  selected by the encoder. Set	the verbosity level to
       verbose or higher to see	the actual settings used by the	QSV runtime.

       Global Options -> MSDK Options

       Additional libavcodec global options are	 mapped	 to  MSDK  options  as
       follows:

          g/gop_size -> GopPicSize

          bf/max_b_frames+1 ->	GopRefDist

          rc_init_occupancy/rc_initial_buffer_occupancy -> InitialDelayInKB

          slices -> NumSlice

          refs	-> NumRefFrame

          b_strategy/b_frame_strategy -> BRefType

          cgop/CLOSED_GOP codec flag -> GopOptFlag

          For	the  CQP mode, the i_qfactor/i_qoffset and b_qfactor/b_qoffset
	   set	the  difference	 between  QPP  and  QPI,  and  QPP   and   QPB
	   respectively.

          Setting  the	 coder	option	to  the	 value vlc will	make the H.264
	   encoder use CAVLC instead of	CABAC.

       Common Options

       Following options are used by all qsv encoders.

       async_depth
	   Specifies how many asynchronous operations an application  performs
	   before the application explicitly synchronizes the result. If zero,
	   the value is	not specified.

       preset
	   This	 option	itemizes a range of choices from veryfast (best	speed)
	   to veryslow (best quality).

	   veryfast
	   faster
	   fast
	   medium
	   slow
	   slower
	   veryslow
       forced_idr
	   Forcing I frames as IDR frames.

       low_power
	   For encoders	set this flag to ON to reduce  power  consumption  and
	   GPU usage.

       Runtime Options

       Following options can be	used durning qsv encoding.

       global_quality
       i_quant_factor
       i_quant_offset
       b_quant_factor
       b_quant_offset
	   Supported  in  h264_qsv  and	hevc_qsv.  Change these	value to reset
	   qsv codec's qp configuration.

       max_frame_size
	   Supported in	h264_qsv and hevc_qsv.	Change this value to reset qsv
	   codec's MaxFrameSize	configuration.

       gop_size
	   Change this value to	reset qsv codec's gop configuration.

       int_ref_type
       int_ref_cycle_size
       int_ref_qp_delta
       int_ref_cycle_dist
	   Supported in	h264_qsv and hevc_qsv.	Change these  value  to	 reset
	   qsv codec's Intra Refresh configuration.

       qmax
       qmin
       max_qp_i
       min_qp_i
       max_qp_p
       min_qp_p
       max_qp_b
       min_qp_b
	   Supported  in  h264_qsv.   Change  these value to reset qsv codec's
	   max/min qp configuration.

       low_delay_brc
	   Supported in	h264_qsv, hevc_qsv and av1_qsv.	 Change	this value  to
	   reset qsv codec's low_delay_brc configuration.

       framerate
	   Change this value to	reset qsv codec's framerate configuration.

       bit_rate
       rc_buffer_size
       rc_initial_buffer_occupancy
       rc_max_rate
	   Change   these   value   to	 reset	qsv  codec's  bitrate  control
	   configuration.

       pic_timing_sei
	   Supported in	h264_qsv and hevc_qsv.	Change this value to reset qsv
	   codec's pic_timing_sei configuration.

       H264 options

       These options are used by h264_qsv

       extbrc
	   Extended bitrate control.

       recovery_point_sei
	   Set this flag to insert the	recovery  point	 SEI  message  at  the
	   beginning of	every intra refresh cycle.

       rdo Enable rate distortion optimization.

       max_frame_size
	   Maximum encoded frame size in bytes.

       max_frame_size_i
	   Maximum  encoded frame size for I frames in bytes. If this value is
	   set as larger than zero,  then  for	I  frames  the	value  set  by
	   max_frame_size is ignored.

       max_frame_size_p
	   Maximum  encoded frame size for P frames in bytes. If this value is
	   set as larger than zero,  then  for	P  frames  the	value  set  by
	   max_frame_size is ignored.

       max_slice_size
	   Maximum encoded slice size in bytes.

       bitrate_limit
	   Toggle  bitrate  limitations.   Modifies bitrate to be in the range
	   imposed by the QSV encoder. Setting	this  flag  off	 may  lead  to
	   violation  of  HRD  conformance. Mind that specifying bitrate below
	   the QSV encoder range might significantly  affect  quality.	If  on
	   this	option takes effect in non CQP modes: if bitrate is not	in the
	   range  imposed  by the QSV encoder, it will be changed to be	in the
	   range.

       mbbrc
	   Setting this	flag enables macroblock	 level	bitrate	 control  that
	   generally  improves	subjective  visual quality. Enabling this flag
	   may have  negative  impact  on  performance	and  objective	visual
	   quality metric.

       low_delay_brc
	   Setting  this  flag	turns  on  or  off  LowDelayBRC	feautre	in qsv
	   plugin, which provides more accurate	bitrate	 control  to  minimize
	   the	variance  of  bitstream	size frame by frame. Value: -1-default
	   0-off 1-on

       adaptive_i
	   This	flag controls insertion	of I frames by the QSV	encoder.  Turn
	   ON this flag	to allow changing of frame type	from P and B to	I.

       adaptive_b
	   This	flag controls changing of frame	type from B to P.

       p_strategy
	   Enable P-pyramid: 0-default 1-simple	2-pyramid(bf need to be	set to
	   0).

       b_strategy
	   This	option controls	usage of B frames as reference.

       dblk_idc
	   This	option disable deblocking. It has value	in range 0~2.

       cavlc
	   If set, CAVLC is used; if unset, CABAC is used for encoding.

       vcm Video conferencing mode, please see ratecontrol method.

       idr_interval
	   Distance (in	I-frames) between IDR frames.

       pic_timing_sei
	   Insert picture timing SEI with pic_struct_syntax element.

       single_sei_nal_unit
	   Put all the SEI messages into one NALU.

       max_dec_frame_buffering
	   Maximum number of frames buffered in	the DPB.

       look_ahead
	   Use VBR algorithm with look ahead.

       look_ahead_depth
	   Depth of look ahead in number frames.

       look_ahead_downsampling
	   Downscaling factor for the frames saved for the lookahead analysis.

	   unknown
	   auto
	   off
	   2x
	   4x
       int_ref_type
	   Specifies  intra  refresh  type. The	major goal of intra refresh is
	   improvement of  error  resilience  without  significant  impact  on
	   encoded bitstream size caused by I frames. The SDK encoder achieves
	   this	 by  encoding  part of each frame in refresh cycle using intra
	   MBs.	none means no refresh. vertical	 means	vertical  refresh,  by
	   column of MBs. horizontal means horizontal refresh, by rows of MBs.
	   slice  means	 horizontal  refresh by	slices without overlapping. In
	   case	of  slice,  in_ref_cycle_size  is  ignored.  To	 enable	 intra
	   refresh, B frame should be set to 0.

       int_ref_cycle_size
	   Specifies  number of	pictures within	refresh	cycle starting from 2.
	   0 and 1 are invalid values.

       int_ref_qp_delta
	   Specifies QP	difference for inserted	 intra	MBs.  This  is	signed
	   value  in  [-51,  51]  range	 if target encoding bit-depth for luma
	   samples is 8	and this range is [-63,	63] for	10 bit-depth or	 [-75,
	   75] for 12 bit-depth	respectively.

       int_ref_cycle_dist
	   Distance  between  the  beginnings  of  the intra-refresh cycles in
	   frames.

       profile
	   unknown
	   baseline
	   main
	   high
       a53cc
	   Use A53 Closed Captions (if available).

       aud Insert the Access Unit Delimiter NAL.

       mfmode
	   Multi-Frame Mode.

	   off
	   auto
       repeat_pps
	   Repeat pps for every	frame.

       max_qp_i
	   Maximum video quantizer scale for I frame.

       min_qp_i
	   Minimum video quantizer scale for I frame.

       max_qp_p
	   Maximum video quantizer scale for P frame.

       min_qp_p
	   Minimum video quantizer scale for P frame.

       max_qp_b
	   Maximum video quantizer scale for B frame.

       min_qp_b
	   Minimum video quantizer scale for B frame.

       scenario
	   Provides a hint to encoder about  the  scenario  for	 the  encoding
	   session.

	   unknown
	   displayremoting
	   videoconference
	   archive
	   livestreaming
	   cameracapture
	   videosurveillance
	   gamestreaming
	   remotegaming
       avbr_accuracy
	   Accuracy of the AVBR	ratecontrol (unit of tenth of percent).

       avbr_convergence
	   Convergence of the AVBR ratecontrol (unit of	100 frames)

	   The	parameters  avbr_accuracy  and	avbr_convergence  are  for the
	   average variable bitrate control (AVBR) algorithm.	The  algorithm
	   focuses  on	overall	 encoding  quality while meeting the specified
	   bitrate, target_bitrate, within the accuracy	 range	avbr_accuracy,
	   after  a  avbr_Convergence  period. This method does	not follow HRD
	   and the instant bitrate is not capped or padded.

       skip_frame
	   Use	per-frame  metadata  "qsv_skip_frame"  to  skip	  frame	  when
	   encoding. This option defines the usage of this metadata.

	   no_skip
	       Frame skipping is disabled.

	   insert_dummy
	       Encoder	inserts	into bitstream frame where all macroblocks are
	       encoded as skipped.

	   insert_nothing
	       Similar to  insert_dummy,  but  encoder	inserts	 nothing  into
	       bitstream.  The	skipped	 frames	 are  still  used  in brc. For
	       example,	gop still include skipped frames, and the frames after
	       skipped frames will be larger in	size.

	   brc_only
	       skip_frame metadata  indicates  the  number  of	missed	frames
	       before the current frame.

       HEVC Options

       These options are used by hevc_qsv

       extbrc
	   Extended bitrate control.

       recovery_point_sei
	   Set	this  flag  to	insert	the  recovery point SEI	message	at the
	   beginning of	every intra refresh cycle.

       rdo Enable rate distortion optimization.

       max_frame_size
	   Maximum encoded frame size in bytes.

       max_frame_size_i
	   Maximum encoded frame size for I frames in bytes. If	this value  is
	   set	as  larger  than  zero,	 then  for  I  frames the value	set by
	   max_frame_size is ignored.

       max_frame_size_p
	   Maximum encoded frame size for P frames in bytes. If	this value  is
	   set	as  larger  than  zero,	 then  for  P  frames the value	set by
	   max_frame_size is ignored.

       max_slice_size
	   Maximum encoded slice size in bytes.

       mbbrc
	   Setting this	flag enables macroblock	 level	bitrate	 control  that
	   generally  improves	subjective  visual quality. Enabling this flag
	   may have  negative  impact  on  performance	and  objective	visual
	   quality metric.

       low_delay_brc
	   Setting  this  flag	turns  on  or  off  LowDelayBRC	feautre	in qsv
	   plugin, which provides more accurate	bitrate	 control  to  minimize
	   the	variance  of  bitstream	size frame by frame. Value: -1-default
	   0-off 1-on

       adaptive_i
	   This	flag controls insertion	of I frames by the QSV	encoder.  Turn
	   ON this flag	to allow changing of frame type	from P and B to	I.

       adaptive_b
	   This	flag controls changing of frame	type from B to P.

       p_strategy
	   Enable P-pyramid: 0-default 1-simple	2-pyramid(bf need to be	set to
	   0).

       b_strategy
	   This	option controls	usage of B frames as reference.

       dblk_idc
	   This	option disable deblocking. It has value	in range 0~2.

       idr_interval
	   Distance (in	I-frames) between IDR frames.

	   begin_only
	       Output an IDR-frame only	at the beginning of the	stream.

       load_plugin
	   A user plugin to load in an internal	session.

	   none
	   hevc_sw
	   hevc_hw
       load_plugins
	   A :-separate	list of	hexadecimal plugin UIDs	to load	in an internal
	   session.

       look_ahead_depth
	   Depth  of look ahead	in number frames, available when extbrc	option
	   is enabled.

       profile
	   Set the encoding profile (scc requires libmfx >= 1.32).

	   unknown
	   main
	   main10
	   mainsp
	   rext
	   scc
       tier
	   Set the encoding tier (only level >=	 4  can	 support  high	tier).
	   This	option only takes effect when the level	option is specified.

	   main
	   high
       gpb 1: GPB (generalized P/B frame)

	   0: regular P	frame.

       tile_cols
	   Number of columns for tiled encoding.

       tile_rows
	   Number of rows for tiled encoding.

       aud Insert the Access Unit Delimiter NAL.

       pic_timing_sei
	   Insert picture timing SEI with pic_struct_syntax element.

       transform_skip
	   Turn	 this  option  ON  to enable transformskip. It is supported on
	   platform equal or newer than	ICL.

       int_ref_type
	   Specifies intra refresh type. The major goal	of  intra  refresh  is
	   improvement	of  error  resilience  without	significant  impact on
	   encoded bitstream size caused by I frames. The SDK encoder achieves
	   this	by encoding part of each frame in refresh  cycle  using	 intra
	   MBs.	 none  means  no  refresh. vertical means vertical refresh, by
	   column of MBs. horizontal means horizontal refresh, by rows of MBs.
	   slice means horizontal refresh by slices  without  overlapping.  In
	   case	 of  slice,  in_ref_cycle_size	is  ignored.  To  enable intra
	   refresh, B frame should be set to 0.

       int_ref_cycle_size
	   Specifies number of pictures	within refresh cycle starting from  2.
	   0 and 1 are invalid values.

       int_ref_qp_delta
	   Specifies  QP  difference  for  inserted  intra MBs.	This is	signed
	   value in [-51, 51] range if	target	encoding  bit-depth  for  luma
	   samples  is 8 and this range	is [-63, 63] for 10 bit-depth or [-75,
	   75] for 12 bit-depth	respectively.

       int_ref_cycle_dist
	   Distance between the	beginnings  of	the  intra-refresh  cycles  in
	   frames.

       max_qp_i
	   Maximum video quantizer scale for I frame.

       min_qp_i
	   Minimum video quantizer scale for I frame.

       max_qp_p
	   Maximum video quantizer scale for P frame.

       min_qp_p
	   Minimum video quantizer scale for P frame.

       max_qp_b
	   Maximum video quantizer scale for B frame.

       min_qp_b
	   Minimum video quantizer scale for B frame.

       scenario
	   Provides  a	hint  to  encoder  about the scenario for the encoding
	   session.

	   unknown
	   displayremoting
	   videoconference
	   archive
	   livestreaming
	   cameracapture
	   videosurveillance
	   gamestreaming
	   remotegaming
       avbr_accuracy
	   Accuracy of the AVBR	ratecontrol (unit of tenth of percent).

       avbr_convergence
	   Convergence of the AVBR ratecontrol (unit of	100 frames)

	   The parameters  avbr_accuracy  and  avbr_convergence	 are  for  the
	   average  variable  bitrate control (AVBR) algorithm.	 The algorithm
	   focuses on overall encoding quality	while  meeting	the  specified
	   bitrate,  target_bitrate,  within the accuracy range	avbr_accuracy,
	   after a avbr_Convergence period. This method	does  not  follow  HRD
	   and the instant bitrate is not capped or padded.

       skip_frame
	   Use	 per-frame   metadata  "qsv_skip_frame"	 to  skip  frame  when
	   encoding. This option defines the usage of this metadata.

	   no_skip
	       Frame skipping is disabled.

	   insert_dummy
	       Encoder inserts into bitstream frame where all macroblocks  are
	       encoded as skipped.

	   insert_nothing
	       Similar	to  insert_dummy,  but	encoder	 inserts  nothing into
	       bitstream. The skipped  frames  are  still  used	 in  brc.  For
	       example,	gop still include skipped frames, and the frames after
	       skipped frames will be larger in	size.

	   brc_only
	       skip_frame  metadata  indicates	the  number  of	 missed	frames
	       before the current frame.

       MPEG2 Options

       These options are used by mpeg2_qsv

       profile
	   unknown
	   simple
	   main
	   high

       VP9 Options

       These options are used by vp9_qsv

       profile
	   unknown
	   profile0
	   profile1
	   profile2
	   profile3
       tile_cols
	   Number of columns for tiled encoding	(requires libmfx >= 1.29).

       tile_rows
	   Number of rows for tiled encoding (requires libmfx  >= 1.29).

       AV1 Options

       These options are used by av1_qsv (requires libvpl).

       profile
	   unknown
	   main
       tile_cols
	   Number of columns for tiled encoding.

       tile_rows
	   Number of rows for tiled encoding.

       adaptive_i
	   This	flag controls insertion	of I frames by the QSV	encoder.  Turn
	   ON this flag	to allow changing of frame type	from P and B to	I.

       adaptive_b
	   This	flag controls changing of frame	type from B to P.

       b_strategy
	   This	option controls	usage of B frames as reference.

       extbrc
	   Extended bitrate control.

       look_ahead_depth
	   Depth  of look ahead	in number frames, available when extbrc	option
	   is enabled.

       low_delay_brc
	   Setting this	flag turns  on	or  off	 LowDelayBRC  feautre  in  qsv
	   plugin,  which  provides  more accurate bitrate control to minimize
	   the variance	of bitstream size frame	by  frame.  Value:  -1-default
	   0-off 1-on

       max_frame_size
	   Set the allowed max size in bytes for each frame. If	the frame size
	   exceeds the limitation, encoder will	adjust the QP value to control
	   the frame size.  Invalid in CQP rate	control	mode.

   snow
       Options

       iterative_dia_size
	   dia size for	the iterative motion estimation

   VAAPI encoders
       Wrappers	for hardware encoders accessible via VAAPI.

       These  encoders	only  accept input in VAAPI hardware surfaces.	If you
       have input in software frames, use the hwupload filter to  upload  them
       to the GPU.

       The following standard libavcodec options are used:

          g / gop_size

          bf /	max_b_frames

          profile

	   If  not  set, this will be determined automatically from the	format
	   of the input	frames and the profiles	supported by the driver.

          level

          b / bit_rate

          maxrate / rc_max_rate

          bufsize / rc_buffer_size

          rc_init_occupancy / rc_initial_buffer_occupancy

          compression_level

	   Speed / quality tradeoff: higher values are faster /	worse quality.

          q / global_quality

	   Size	/ quality tradeoff: higher values are smaller /	worse quality.

          qmin

          qmax

          i_qfactor / i_quant_factor

          i_qoffset / i_quant_offset

          b_qfactor / b_quant_factor

          b_qoffset / b_quant_offset

          slices

       All encoders support the	following options:

       low_power
	   Some	drivers/platforms offer	 a  second  encoder  for  some	codecs
	   intended  to	 use less power	than the default encoder; setting this
	   option will attempt to use that encoder.  Note that it may  support
	   a  reduced  feature set, so some other options may not be available
	   in this mode.

       idr_interval
	   Set the number of normal intra frames  between  full-refresh	 (IDR)
	   frames  in  open-GOP	 mode.	 The intra frames are still IRAPs, but
	   will	not include global headers and may have	non-decodable  leading
	   pictures.

       b_depth
	   Set	the  B-frame  reference	depth.	When set to one	(the default),
	   all B-frames	will refer only	 to  P-	 or  I-frames.	 When  set  to
	   greater  values multiple layers of B-frames will be present,	frames
	   in each layer only referring	to frames in higher layers.

       async_depth
	   Maximum processing parallelism. Increase  this  to  improve	single
	   channel  performance.  This	option	doesn't	work if	driver doesn't
	   implement vaSyncBuffer function. Please make	sure there are	enough
	   hw_frames allocated if a large number of async_depth	is used.

       max_frame_size
	   Set the allowed max size in bytes for each frame. If	the frame size
	   exceeds the limitation, encoder will	adjust the QP value to control
	   the frame size.  Invalid in CQP rate	control	mode.

       rc_mode
	   Set	the rate control mode to use.  A given driver may only support
	   a subset of modes.

	   Possible modes:

	   auto
	       Choose the mode automatically based on driver support  and  the
	       other options.  This is the default.

	   CQP Constant-quality.

	   CBR Constant-bitrate.

	   VBR Variable-bitrate.

	   ICQ Intelligent constant-quality.

	   QVBR
	       Quality-defined variable-bitrate.

	   AVBR
	       Average variable	bitrate.

       Each encoder also has its own specific options:

       av1_vaapi
	   profile  sets  the  value  of  seq_profile.	tier sets the value of
	   seq_tier.  level sets the value of seq_level_idx.

	   tiles
	       Set the number of tiles to encode  the  input  video  with,  as
	       columns x rows.	(default is auto, which	means use minimal tile
	       column/row number).

	   tile_groups
	       Set  tile  groups  number. All the tiles	will be	distributed as
	       evenly as possible to each tile group. (default is 1).

       h264_vaapi
	   profile    sets    the    value    of    profile_idc	   and	   the
	   constraint_set*_flags.  level sets the value	of level_idc.

	   coder
	       Set entropy encoder (default is cabac).	Possible values:

	       ac
	       cabac
		   Use CABAC.

	       vlc
	       cavlc
		   Use CAVLC.

	   aud Include	access	unit delimiters	in the stream (not included by
	       default).

	   sei Set SEI message types to	 include.   Some  combination  of  the
	       following values:

	       identifier
		   Include   a	 user_data_unregistered	  message   containing
		   information about the encoder.

	       timing
		   Include picture  timing  parameters	(buffering_period  and
		   pic_timing messages).

	       recovery_point
		   Include  recovery  points where appropriate (recovery_point
		   messages).

       hevc_vaapi
	   profile  and	 level	set  the  values  of  general_profile_idc  and
	   general_level_idc respectively.

	   aud Include	access	unit delimiters	in the stream (not included by
	       default).

	   tier
	       Set general_tier_flag.  This may	affect the  level  chosen  for
	       the stream if it	is not explicitly specified.

	   sei Set  SEI	 message  types	 to  include.  Some combination	of the
	       following values:

	       hdr Include  HDR	 metadata  if  the  input   frames   have   it
		   (mastering_display_colour_volume   and  content_light_level
		   messages).

	   tiles
	       Set the number of tiles to encode  the  input  video  with,  as
	       columns	x  rows.   Larger numbers allow	greater	parallelism in
	       both encoding and decoding, but may decrease coding efficiency.

       mjpeg_vaapi
	   Only	baseline DCT encoding is supported.  The encoder  always  uses
	   the	standard  quantisation	and  huffman  tables  -	global_quality
	   scales the standard quantisation table (range 1-100).

	   For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling	modes  are  supported.
	   RGB is also supported, and will create an RGB JPEG.

	   jfif
	       Include JFIF header in each frame (not included by default).

	   huffman
	       Include	standard huffman tables	(on by default).  Turning this
	       off will	save a few hundred bytes in each output	frame, but may
	       lose compatibility with some JPEG decoders  which  don't	 fully
	       handle MJPEG.

       mpeg2_vaapi
	   profile and level set the value of profile_and_level_indication.

       vp8_vaapi
	   B-frames are	not supported.

	   global_quality  sets	 the  q_idx  used  for	non-key	 frames	(range
	   0-127).

	   loop_filter_level
	   loop_filter_sharpness
	       Manually	set the	loop filter parameters.

       vp9_vaapi
	   global_quality sets the q_idx used for P-frames (range 0-255).

	   loop_filter_level
	   loop_filter_sharpness
	       Manually	set the	loop filter parameters.

	   B-frames are	supported, but the output stream is always  in	encode
	   order  rather  than display order.  If B-frames are enabled,	it may
	   be necessary	to use the vp9_raw_reorder bitstream filter to	modify
	   the output stream to	display	frames in the correct order.

	   Only	 normal	 frames	 are  produced	- the vp9_superframe bitstream
	   filter may  be  required  to	 produce  a  stream  usable  with  all
	   decoders.

   vbn
       Vizrt Binary Image encoder.

       This  format  is	 used  by the broadcast	vendor Vizrt for quick texture
       streaming.  Advanced features of	the format such	as LZW compression  of
       texture data or generation of mipmaps are not supported.

       Options

       format string
	   Sets	 the  texture  compression  used by the	VBN file. Can be dxt1,
	   dxt5	or raw.	Default	is dxt5.

   vc2
       SMPTE VC-2 (previously BBC Dirac	Pro). This codec was  primarily	 aimed
       at  professional	 broadcasting but since	it supports yuv420, yuv422 and
       yuv444 at 8 (limited range or full range), 10 or	12 bits, this makes it
       suitable	for other tasks	which require low overhead and low compression
       (like screen recording).

       Options

       b   Sets	target	video  bitrate.	 Usually  that's  around  1:6  of  the
	   uncompressed	 video	bitrate	 (e.g.	for  1920x1080 50fps yuv422p10
	   that's around 400Mbps). Higher values (close	 to  the  uncompressed
	   bitrate) turn on lossless compression mode.

       field_order
	   Enables  field  coding  when	set (e.g. to tt	- top field first) for
	   interlaced inputs.  Should  increase	 compression  with  interlaced
	   content as it splits	the fields and encodes each separately.

       wavelet_depth
	   Sets	the total amount of wavelet transforms to apply, between 1 and
	   5  (default).   Lower  values  reduce compression and quality. Less
	   capable decoders may	not be able to handle values of	 wavelet_depth
	   over	3.

       wavelet_type
	   Sets	 the  transform	 type.	Currently  only	 5_3  (LeGall) and 9_7
	   (Deslauriers-Dubuc) are implemented,	with 9_7 being	the  one  with
	   better compression and thus is the default.

       slice_width
       slice_height
	   Sets	 the slice size	for each slice.	Larger values result in	better
	   compression.	 For compatibility with	other  more  limited  decoders
	   use slice_width of 32 and slice_height of 8.

       tolerance
	   Sets	 the  undershoot  tolerance  of	 the  rate  control  system in
	   percent. This is to prevent an expensive search from	being run.

       qm  Sets	the quantization matrix	preset	to  use	 by  default  or  when
	   wavelet_depth is set	to 5

	   -   default	 Uses	the   default  quantization  matrix  from  the
	       specifications, extended	with values for	the fifth level.  This
	       provides	 a  good  balance  between keeping detail and omitting
	       artifacts.

	   -   flat Use	a completely  zeroed  out  quantization	 matrix.  This
	       increases  PSNR	but  might  reduce  perception.	 Use  in bogus
	       benchmarks.

	   -   color  Reduces  detail  but  attempts  to  preserve  color   at
	       extremely low bitrates.

SUBTITLES ENCODERS
   dvdsub
       This  codec  encodes  the  bitmap subtitle format that is used in DVDs.
       Typically they are stored in VOBSUB file	pairs  (*.idx  +  *.sub),  and
       they can	also be	used in	Matroska files.

       Options

       palette
	   Specify the global palette used by the bitmaps.

	   The	format	for  this  option  is  a  string containing 16 24-bits
	   hexadecimal numbers (without	0x prefix) separated  by  commas,  for
	   example  "0d00ee,  ee450d,  101010, eaeaea, 0ce60b, ec14ed, ebff0b,
	   0d617a, 7b7b7b, d1d1d1, 7b2a0e,  0d950c,  0f007b,  cf0dec,  cfa80c,
	   7c127b".

       even_rows_fix
	   When	 set to	1, enable a work-around	that makes the number of pixel
	   rows	even in	all subtitles.	This fixes a problem with some players
	   that	cut off	the bottom row if the number is	odd.  The  work-around
	   just	 adds a	fully transparent row if needed.  The overhead is low,
	   typically one byte per subtitle on average.

	   By default, this work-around	is disabled.

SEE ALSO
       ffmpeg(1), ffplay(1), ffprobe(1), libavcodec(3)

AUTHORS
       The FFmpeg developers.

       For details about the authorship, see the Git history  of  the  project
       (https://git.ffmpeg.org/ffmpeg),	 e.g. by typing	the command git	log in
       the FFmpeg source directory,  or	 browsing  the	online	repository  at
       <https://git.ffmpeg.org/ffmpeg>.

       Maintainers  for	 the  specific	components  are	 listed	 in  the  file
       MAINTAINERS in the source code tree.

							      FFMPEG-CODECS(1)

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