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XvQueryEncodings

XvQueryEncodings

Section: libXv Functions (3) Updated: libXv 1.0.6
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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 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.  

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)


 

Index

NAME
SYNOPSIS
ARGUMENTS
DESCRIPTION
RETURN VALUES
DIAGNOSTICS
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 21:59:19 GMT, April 16, 2011