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XvQueryEncodings(3)                                        XvQueryEncodings(3)




Name

       XvQueryEncodings - return list of encodings for an adaptor


Syntax

       #include <X11/extensions/Xvlib.h>

       XvQueryEncodings(Display *dpy, XvPortID port,
                        unsigned int *p_num_encodings,
                        XvEncodingInfo **pp_encoding_info);


Arguments

       dpy     Specifies the connection to the X server.

       XvPortID
               Specifies  the port whose adaptor is to be queried for its list
               of encodings.

       p_num_encodings
               A pointer to where the number of  encodings  supported  by  the
               adaptor is written.

       pp_encoding_info
               A pointer to where the list of returned encoding information is
               returned.  XvEncodingInfo has the following structure:

                   typedef struct {
                     XvEncodingID encoding_id;
                     char *name;
                     unsigned long width;
                     unsigned long height;
                     XvRational rate;
                     unsigned long num_encodings;
                   } XvEncodingInfo;


       encoding_id
               Specifies the encoding-id of the encoding.  The encoding-id  is
               used  to  identify an encoding when a port's encoding attribute
               is changed.

       name    A pointer to a formatted string that identifies  the  encoding.
               The  string  has  the  format "timing-signaltype".  For example
               "ntsc-composite".

       width,height
               The width and height, in pixels, of the decoded video image.

       rate    The field rate of the decoded video.

       The XvRational structure is used to specify a  fractional  number.   It
       has the following structure:

           typedef struct {
             int numerator;
             int denominator;
           } XvRational;

       The numerator and denominator fields specify the appropriate parts of a
       fractional number.


Description

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


Returned Values

       [Success]
               Returned if XvQueryEncodings(3) completed successfully.

       [XvBadExtension]
               Returned if the Xv extension is unavailable.

       [XvBadAlloc]
               Returned  if  XvQueryEncodings(3)  failed to allocate memory to
               process the request.


Diagnostics

       [XvBadPort]
               Generated if the requested port does not exist.


See Also

       XvFreeEncodingInfo(3)



X Version 11                      libXv 1.0.4              XvQueryEncodings(3)

Mac OS X 10.6 X11 - Generated Sun Mar 7 12:33:22 CST 2010
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