XvQueryAdaptors (3)

#include <X11/extensions/Xvlib.h>

int XvQueryAdaptors(Display *dpy, Window window,
                    unsigned int *p_num_adaptors,
                    XvAdaptorInfo **pp_adaptor_info);

dpy

Specifies the connection to the X server.

window

Specifies a window of the screen for which the adaptor information is desired.

p_num_adaptors

A pointer to where the number of adaptors for the specified screen is returned.

pp_adaptor_info

A pointer to where the list of returned adaptor information is returned.

XvQueryAdaptors(3) returns an video adaptor information for the screen of the specified drawable. The XvAdaptorInfo structure has the following organization:

     typedef struct {
       XvPortID base_id;
       unsigned long num_ports;
       char type;
       char *name;
       unsigned long num_formats;
       XvFormat *formats;
       unsigned long num_adaptors;
     } XvAdaptorInfo;

base_id

The resource ID of the first adaptor port.

num_ports

The number of ports supported by the adaptor.

type

A bit mask with the value XvInputMask asserted if the adaptor supports video input, and value XvOutputMask asserted if the adaptor supports video output. In Xv protocol 2.2 and later, there are 3 new bits defined - XvVideoMask, XvStillMask and XvImageMask indicating that the adaptor is capable of video, still or image primitives respectively.

name

A vendor specific name that identifies the adaptor.

num_formats

The number of depth/visual id formats supported by the adaptor.

formats

A pointer to an array of XvFormat structures.

The XvFormat structure has the following organization:

     typedef struct {
       char depth;
       unsigned long visual_id;
     } XvFormat;

depth

A drawable depth supported by the adaptor.

visual_id

A visual-id supported for the given depth by the adaptor.

[Success]

Returned if XvQueryAdaptors(3) completed successfully.

[XvBadExtension]

Returned if the Xv extension is unavailable.

[XvBadAlloc]

Returned if XvQueryAdaptors(3) failed to allocate memory to process the request.

[Drawable]

Returned if the requested drawable does not exist.

XvFreeAdaptorInfo(3)