1XvQueryEncodings(3)        Library Functions Manual        XvQueryEncodings(3)
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Name

6       XvQueryEncodings - return list of encodings for an adaptor
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Syntax

9       #include <X11/extensions/Xvlib.h>
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11       XvQueryEncodings(dpy, port, p_num_encodings, pp_encoding_info)
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13       register Display *dpy;
14       XvPortID port;
15       unsigned long *p_num_encodings;
16       XvEncodingInfo **pp_encoding_info;
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Arguments

19       *dpy           Specifies the connection to the X server.
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21       port           Specifies  the  port  whose adaptor is to be queried for
22                      its list of encodings.
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24       p_num_encodings
25                      A pointer to where the number of encodings supported  by
26                      the adaptor is written.
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28       pp_encoding_info
29                      A  pointer to where the list of returned encoding infor‐
30                      mation is returned.  XvEncodingInfo  has  the  following
31                      structure:
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33                          typedef struct {
34                            XvEncodingID encoding_id;
35                            char *name;
36                            unsigned long width;
37                            unsigned long height;
38                            XvRational rate;
39                            unsigned long num_encodings;
40                          } XvEncodingInfo;
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42
43       encoding_id    Specifies  the  encoding-id of the encoding.  The encod‐
44                      ing-id is used to identify an  encoding  when  a  port's
45                      encoding attribute is changed.
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47       name           A  pointer  to  a  formatted  string that identifies the
48                      encoding.  The string  has  the  format  "timing-signal‐
49                      type".  For example "ntsc-composite".
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51       width,height   The  width  and  height, in pixels, of the decoded video
52                      image.
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54       rate           The field rate of the decoded video.
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56       The XvRational structure is used to specify a  fractional  number.   It
57       has the following structure:
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59           typedef struct {
60             int numerator;
61             int denominator;
62           } XvRational;
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64       The numerator and denominator fields specify the appropriate parts of a
65       fractional number.
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Description

68       XvQueryEncodings(3) returns  encoding  information  about  an  adaptor.
69       Each  encoding  is  described by the XvEncodingInfo structure described
70       above.  The encodings are identified by an encoding-id,  which  can  be
71       used to set or get the encoding attribute of a port.
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Returned Values

74       [Success]
75               Returned if XvQueryEncodings(3) completed successfully.
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77       [XvBadExtension]
78               Returned if the Xv extension is unavailable.
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80       [XvBadAlloc]
81               Returned  if  XvQueryEncodings(3)  failed to allocate memory to
82               process the request.
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Diagnostics

85       [XvBadPort]
86               Generated if the requested port does not exist.
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See Also

89       XvFreeEncodingInfo(3)
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93X Version 11                      libXv 1.0.3              XvQueryEncodings(3)
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