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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 adaptors 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 multi-
       ple drawable formats.

       Clients use Xv(3) to gain access and manage sharing of a display's video resources.  Typi-
       cally,  a  client  will	use XvQueryExtension(3) to determine the status of the extension,
       XvQueryAdaptors(3) to get a description of what video adaptors  exist,  and  XvQueryEncod-
       ings(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,  according  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  images  in	alternate
       colorspaces  (XvImages).   Xv  adaptors which are capable of displaying XvImages will have
       the XvImageMask field set in the type field of the XvAdaptorInfo.   XvImage  formats  sup-
       ported  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  attributes  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.

       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 1.0.9					    Xv(3)
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