redhat man page for xvqueryencodings

XvQueryEncodings(3X)													      XvQueryEncodings(3X)

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  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.

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

       [XvBadExtension]
	       Returned if the Xv extension is unavailable.

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

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

See Also
       XvFreeEncodingInfo(3X)

XFree86 						       Version Version 4.3.0					      XvQueryEncodings(3X)