XvQueryEncodings(3)

Name

       XvQueryEncodings - return list of encodings for an adaptor

Syntax

       #include <X11/extensions/Xvlib.h>

       XvQueryEncodings(dpy, port, p_num_encodings, pp_encoding_info)

       register Display *dpy;
       XvPortID port;
       unsigned long *p_num_encodings;
       XvEncodingInfo **pp_encoding_info;

Arguments

       *dpy           Specifies the connection to the X server.

       port           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 infor-
                      mation 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 encod-
                      ing-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-signal-
                      type".  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 1.0.3              XvQueryEncodings(3)