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Xv(3)				libXv Functions				 Xv(3)

NAME
       Xv - X Window System video extension

DESCRIPTION
       The  X  Video Extension (Xv) extension provides support for video adap-
       tors attached to	an X display.  It takes	the approach  that  a  display
       may  have  one  or  more	 video adaptors, each of which has one or more
       ports through which independent video streams pass.

       An adaptor may be able to display video in a  drawable,	capture	 video
       from  a drawable, or both.  It translates between video encoding	(NTSC,
       PAL, SECAM, etc...) and drawable	format (depth and visual-id pair).  An
       adaptor	may  support multiple video encodings and/or multiple drawable
       formats.

       Clients use Xv(3) to gain access	and  manage  sharing  of  a  display's
       video  resources.   Typically, a	client will use	XvQueryExtension(3) to
       determine the status of the extension, XvQueryAdaptors(3) to get	a  de-
       scription  of what video	adaptors exist,	and XvQueryEncodings(3)	to get
       a description of	what video encodings an	adaptor	supports.

       Once a client has determined what video resources are available,	it  is
       free to put video into a	drawable or get	video from a drawable, accord-
       ing  the	 capabilities supported.  Clients can select to	receive	events
       when video activity changes in a	drawable and when port attributes have
       changed.

       The Xv protocol version 2.2 and later is	extended to support client im-
       ages in alternate colorspaces (XvImages).  Xv adaptors which are	 capa-
       ble  of	displaying XvImages will have the XvImageMask field set	in the
       type field of the XvAdaptorInfo.	 XvImage formats supported by the port
       may be queried with XvListImageFormats(3).   XvImages  may  be  created
       with  the help of XvCreateImage(3) or XvShmCreateImage(3); XvImages may
       be displayed with XvPutImage(3) or XvShmPutImage(3).  The Port  attrib-
       utes of the port	specified in the Xv(Shm)PutImage command will be valid
       for the image operation when applicable.	 There will be a port encoding
       with  the  name "XV_IMAGE".  The	width and height of that encoding will
       indicate	the maximum source image size.

SUMMARY	OF LIBRARY FUNCTIONS
       The following is	a summary of Xv	library	functions and events:

       XvCreateImage(3)	- create an XvImage

       XvGetPortAttribute(3) - return current port attribute value

       XvGetStill(3) - capture a single	frame of video from a drawable

       XvGetVideo(3) - capture video from a drawable

       XvGrabPort(3) - lock port for exclusive use by client

       XvListImageFormats(3) - return list of image formats for	a port

       XvPortNotify(3) - event generated when port attributes change

       XvPutImage(3) - write a XvImage to a drawable

       XvPutStill(3) - write a single frame of video to	a drawable

       XvPutVideo(3) - write video into	a drawable

       XvQueryAdaptors(3) - return adaptor information for a screen

       XvQueryBestSize(3) - determine the optimum drawable region size

       XvQueryEncodings(3) - return list of encodings for an adaptor

       XvQueryExtension(3) - return version and	revision of extension

       XvQueryPortAttributes(3)	- return list of attributes of a port

       XvSelectPortNotify(3) - enable or disable XvPortNotify events

       XvSelectVideoNotify(3) -	enable or disable XvVideoNotify	events

       XvSetPortAttribute(3) - set an attribute	for a port

       XvShmCreateImage(3) - create an XvImage in shared memory

       XvShmPutImage(3)	- write	a XvImage in shared memory to a	drawable

       XvStopVideo(3) -	stop active video

       XvUngrabPort(3) - release a grabbed port

       XvVideoNotify(3)	- event	generated for video processing

       Each of these functions and events is described in its own Xv man page.

X Version 11			 libXv 1.0.12				 Xv(3)

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