XvQueryEncodings(3) XvQueryEncodings(3)
Name
XvQueryEncodings - return list of encodings for an adaptor
Syntax
#include <X11/extensions/Xvlib.h>
XvQueryEncodings(Display *dpy, XvPortID port,
unsigned int *p_num_encodings,
XvEncodingInfo **pp_encoding_info);
Arguments
dpy Specifies the connection to the X server.
XvPortID
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.
Returned 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 1.0.4 XvQueryEncodings(3)
Mac OS X 10.6 X11 - Generated Sun Mar 7 12:33:22 CST 2010