1Xv(3)                           libXv Functions                          Xv(3)
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NAME

6       Xv - X Window System video extension
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DESCRIPTION

9       The  X  Video Extension (Xv) extension provides support for video adap‐
10       tors attached to an X display.  It takes the approach  that  a  display
11       may  have  one  or  more  video adaptors, each of which has one or more
12       ports through which independent video streams pass.
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14       An adaptor may be able to display video in a  drawable,  capture  video
15       from  a drawable, or both.  It translates between video encoding (NTSC,
16       PAL, SECAM, etc...) and drawable format (depth and visual-id pair).  An
17       adaptor  may  support multiple video encodings and/or multiple drawable
18       formats.
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20       Clients use Xv(3) to gain access and  manage  sharing  of  a  display's
21       video  resources.   Typically, a client will use XvQueryExtension(3) to
22       determine the status of the  extension,  XvQueryAdaptors(3)  to  get  a
23       description  of  what  video adaptors exist, and XvQueryEncodings(3) to
24       get a description of what video encodings an adaptor supports.
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26       Once a client has determined what video resources are available, it  is
27       free to put video into a drawable or get video from a drawable, accord‐
28       ing the capabilities supported.  Clients can select to  receive  events
29       when video activity changes in a drawable and when port attributes have
30       changed.
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32       The Xv protocol version 2.2 and later is  extended  to  support  client
33       images  in  alternate  colorspaces  (XvImages).   Xv adaptors which are
34       capable of displaying XvImages will have the XvImageMask field  set  in
35       the  type field of the XvAdaptorInfo.  XvImage formats supported by the
36       port may be queried with XvListImageFormats(3).  XvImages may  be  cre‐
37       ated with the help of XvCreateImage(3) or XvShmCreateImage(3); XvImages
38       may be displayed with  XvPutImage(3)  or  XvShmPutImage(3).   The  Port
39       attributes of the port specified in the Xv(Shm)PutImage command will be
40       valid for the image operation when applicable.  There will  be  a  port
41       encoding with the name "XV_IMAGE".  The width and height of that encod‐
42       ing will indicate the maximum source image size.
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SUMMARY OF LIBRARY FUNCTIONS

45       The following is a summary of Xv library functions and events:
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47       XvCreateImage(3) - create an XvImage
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49       XvGetPortAttribute(3) - return current port attribute value
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51       XvGetStill(3) - capture a single frame of video from a drawable
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53       XvGetVideo(3) - capture video from a drawable
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55       XvGrabPort(3) - lock port for exclusive use by client
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57       XvListImageFormats(3) - return list of image formats for a port
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59       XvPortNotify(3) - event generated when port attributes change
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61       XvPutImage(3) - write a XvImage to a drawable
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63       XvPutStill(3) - write a single frame of video to a drawable
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65       XvPutVideo(3) - write video into a drawable
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67       XvQueryAdaptors(3) - return adaptor information for a screen
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69       XvQueryBestSize(3) - determine the optimum drawable region size
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71       XvQueryEncodings(3) - return list of encodings for an adaptor
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73       XvQueryExtension(3) - return version and revision of extension
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75       XvQueryPortAttributes(3) - return list of attributes of a port
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77       XvSelectPortNotify(3) - enable or disable XvPortNotify events
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79       XvSelectVideoNotify(3) - enable or disable XvVideoNotify events
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81       XvSetPortAttribute(3) - set an attribute for a port
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83       XvShmCreateImage(3) - create an XvImage in shared memory
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85       XvShmPutImage(3) - write a XvImage in shared memory to a drawable
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87       XvStopVideo(3) - stop active video
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89       XvUngrabPort(3) - release a grabbed port
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91       XvVideoNotify(3) - event generated for video processing
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94       Each of these functions and events is described in its own Xv man page.
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98X Version 11                     libXv 1.0.11                            Xv(3)
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