XvQueryEncodings man page

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)

Referenced By

Xv(3), XvFreeEncodingInfo(3).

libXv 1.0.11 X Version 11 libXv Functions