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XvQueryEncodings(3)		 libXv Functions	     XvQueryEncodings(3)

NAME
     XvQueryEncodings - return list of encodings for an adaptor

SYNOPSIS
     #include <X11/extensions/Xvlib.h>

     int XvQueryEncodings(Display *dpy, XvPortID port,
			  unsigned int *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 information is re-
	     turned.  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-com-
	     posite".

     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.

RETURN 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 1.0.13		     XvQueryEncodings(3)

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