Manual Pages for UNIX Operating System command usage for man Xv

libXv Functions                                           Xv(3xv)



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 indepen-
     dent video streams pass.

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

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

     Once a client has determined what video resources are avail-
     able,  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 adap-
     tors which are capable of displaying XvImages will have  the
     XvImageMask  field  set  in  the  type  field of the XvAdap-
     torInfo.  XvImage formats  supported  by  the  port  may  be
     queried   with  XvListImageFormats(3xv).   XvImages  may  be
     created   with   the   help   of    XvCreateImage(3xv)    or
     XvShmCreateImage(3xv);   XvImages   may  be  displayed  with
     XvPutImage(3xv) or XvShmPutImage(3xv).  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(3xv) - create an XvImage

     XvGetPortAttribute(3xv)  -  return  current  port  attribute
     value



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libXv Functions                                           Xv(3xv)



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

     XvGetVideo(3xv) - capture video from a drawable

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

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

     XvPortNotify(3xv) - event  generated  when  port  attributes
     change

     XvPutImage(3xv) - write a XvImage to a drawable

     XvPutStill(3xv) - write a single frame of video to  a  draw-
     able

     XvPutVideo(3xv) - write video into a drawable

     XvQueryAdaptors(3xv) -  return  adaptor  information  for  a
     screen

     XvQueryBestSize(3xv) - determine the optimum drawable region
     size

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

     XvQueryExtension(3xv)  -  return  version  and  revision  of
     extension

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

     XvSelectPortNotify(3xv) -  enable  or  disable  XvPortNotify
     events

     XvSelectVideoNotify(3xv) - enable or  disable  XvVideoNotify
     events

     XvSetPortAttribute(3xv) - set an attribute for a port

     XvShmCreateImage(3xv) - create an XvImage in shared memory

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

     XvStopVideo(3xv) - stop active video

     XvUngrabPort(3xv) - release a grabbed port




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libXv Functions                                           Xv(3xv)



     XvVideoNotify(3xv) - event generated for video processing


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


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | x11/library/libxv           |
    |_____________________________|_____________________________|
    | Interface Stability         | Volatile                    |
    |_____________________________|_____________________________|
    | MT-Level                    | See XInitThreads(3X11)      |
    |_____________________________|_____________________________|



































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