x11r4 man page for xvqueryencodings

XvQueryEncodings(3)					     Library Functions Manual					       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)