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 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)


X Version 11 libXv 1.0.13 XvQueryEncodings(3)