1XvQueryEncodings(3)             libXv Functions            XvQueryEncodings(3)
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NAME

6       XvQueryEncodings - return list of encodings for an adaptor
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SYNOPSIS

9       #include <X11/extensions/Xvlib.h>
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11       int XvQueryEncodings(Display *dpy, XvPortID port,
12                            unsigned int *p_num_encodings,
13                            XvEncodingInfo **pp_encoding_info);
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ARGUMENTS

16       dpy     Specifies the connection to the X server.
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18       port    Specifies  the port whose adaptor is to be queried for its list
19               of encodings.
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21       p_num_encodings
22               A pointer to where the number of  encodings  supported  by  the
23               adaptor is written.
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25       pp_encoding_info
26               A pointer to where the list of returned encoding information is
27               returned.  XvEncodingInfo has the following structure:
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29                   typedef struct {
30                     XvEncodingID encoding_id;
31                     char *name;
32                     unsigned long width;
33                     unsigned long height;
34                     XvRational rate;
35                     unsigned long num_encodings;
36                   } XvEncodingInfo;
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39       encoding_id
40               Specifies the encoding-id of the encoding.  The encoding-id  is
41               used  to  identify an encoding when a port's encoding attribute
42               is changed.
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44       name    A pointer to a formatted string that identifies  the  encoding.
45               The  string  has  the  format "timing-signaltype".  For example
46               "ntsc-composite".
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48       width,height
49               The width and height, in pixels, of the decoded video image.
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51       rate    The field rate of the decoded video.
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53       The XvRational structure is used to specify a  fractional  number.   It
54       has the following structure:
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56           typedef struct {
57             int numerator;
58             int denominator;
59           } XvRational;
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61       The numerator and denominator fields specify the appropriate parts of a
62       fractional number.
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DESCRIPTION

65       XvQueryEncodings(3) returns  encoding  information  about  an  adaptor.
66       Each  encoding  is  described by the XvEncodingInfo structure described
67       above.  The encodings are identified by an encoding-id,  which  can  be
68       used to set or get the encoding attribute of a port.
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RETURN VALUES

71       [Success]
72               Returned if XvQueryEncodings(3) completed successfully.
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74       [XvBadExtension]
75               Returned if the Xv extension is unavailable.
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77       [XvBadAlloc]
78               Returned  if  XvQueryEncodings(3)  failed to allocate memory to
79               process the request.
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DIAGNOSTICS

82       [XvBadPort]
83               Generated if the requested port does not exist.
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SEE ALSO

86       XvFreeEncodingInfo(3)
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91X Version 11                     libXv 1.0.11              XvQueryEncodings(3)
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