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Xv(3)				libXv Functions				 Xv(3)

       Xv - X Window System video extension

       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

       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

       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  at-
       tributes	 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	encod-
       ing will	indicate the maximum source image size.

       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 1.0.11				 Xv(3)


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