NAME

       Xv - X Window System video extension

DESCRIPTION

       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 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
       description  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, 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  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  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.

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.