XvQueryEncodings(3x)                                      XvQueryEncodings(3x)

       XvQueryEncodings - return list of encodings for an adaptor

       #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;

       *dpy           Specifies the display screen on which the Xv Server is
                      to accept requests from Xv clients.  If the display
                      option is not specified, Xv uses the display screen
                      specified by your DISPLAY environment variable.  The
                      display option has the format hostname:number.  Using
                      two colons (::) instead of one (:) indicates that DECnet
                      is to be used for transport.

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

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

                      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

       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.

       XvQueryEncodings(3x) 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
               Returned if XvQueryEncodings(3x) completed successfully.

               Returned if the Xv extension is unavailable.

               Returned if XvQueryEncodings(3x) failed to allocate memory to
               process the request.

               Generated if the requested port does not exist.

See Also

X Version 11                      libXv 1.0.1             XvQueryEncodings(3x)