Files
libva-v4l2-request-fourier/src/v4l2.h
T
test0r 58a0e8baf9 v4l2: add QUERYCTRL/QUERYMENU capability-probe helpers
Pure utility additions, no behaviour change. Three helpers in
src/v4l2.{c,h}:

  - v4l2_query_ext_ctrl(): wraps VIDIOC_QUERY_EXT_CTRL by CID.
    Returns 0 if the control exists, -1 if not. Caller passes NULL
    qec to test existence only.

  - v4l2_query_menu(): wraps VIDIOC_QUERYMENU at a given index.
    Returns 0 if a menu item exists at that index, -1 otherwise.

  - v4l2_ctrl_menu_has_value(): convenience layered on the above.
    For a menu/intmenu-type control, walks all menu items between
    minimum and maximum and returns true iff `value` is a valid
    entry. Used by callers that ask "does this driver accept menu
    value X for this CID?" without caring about iteration details.

These unblock commit 3 (request_pool — needs ext-ctrl probing for
codec-ops dispatch) and commit 4 (probe-then-set DECODE_MODE/
START_CODE — replaces 0002's unconditional set with a real probe)
of the upstreamable design's six-commit series.

Forward-declarations in v4l2.h keep the header lean: existing
prototypes already use opaque struct v4l2_ext_control * pointers
without including <linux/videodev2.h>; we follow the same
convention for struct v4l2_query_ext_ctrl and struct v4l2_querymenu.

No call sites added in this commit. Compile-only verification:
the .so links cleanly with three new exports.

Signed-off-by: Markus Fritsche <fritsche.markus@gmail.com>
2026-05-04 09:45:05 +00:00

101 lines
4.2 KiB
C

/*
* Copyright (C) 2018 Paul Kocialkowski <paul.kocialkowski@bootlin.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef _V4L2_H_
#define _V4L2_H_
#include <stdbool.h>
#define SOURCE_SIZE_MAX (1024 * 1024)
unsigned int v4l2_type_video_output(bool mplane);
unsigned int v4l2_type_video_capture(bool mplane);
int v4l2_query_capabilities(int video_fd, unsigned int *capabilities);
bool v4l2_find_format(int video_fd, unsigned int type,
unsigned int pixelformat);
int v4l2_set_format(int video_fd, unsigned int type, unsigned int pixelformat,
unsigned int width, unsigned int height);
int v4l2_get_format(int video_fd, unsigned int type, unsigned int *width,
unsigned int *height, unsigned int *bytesperline,
unsigned int *sizes, unsigned int *planes_count);
int v4l2_create_buffers(int video_fd, unsigned int type,
unsigned int buffers_count, unsigned int *index_base);
int v4l2_query_buffer(int video_fd, unsigned int type, unsigned int index,
unsigned int *lengths, unsigned int *offsets,
unsigned int buffers_count);
int v4l2_request_buffers(int video_fd, unsigned int type,
unsigned int buffers_count);
int v4l2_queue_buffer(int video_fd, int request_fd, unsigned int type,
struct timeval *timestamp, unsigned int index,
unsigned int size, unsigned int buffers_count);
int v4l2_dequeue_buffer(int video_fd, int request_fd, unsigned int type,
unsigned int index, unsigned int buffers_count);
int v4l2_export_buffer(int video_fd, unsigned int type, unsigned int index,
unsigned int flags, int *export_fds,
unsigned int export_fds_count);
int v4l2_get_controls(int video_fd, int request_fd,
struct v4l2_ext_control *controls,
unsigned int num_controls);
int v4l2_set_controls(int video_fd, int request_fd,
struct v4l2_ext_control *controls,
unsigned int num_controls);
int v4l2_set_control(int video_fd, int request_fd, unsigned int id, void *data,
unsigned int size);
int v4l2_set_stream(int video_fd, unsigned int type, bool enable);
/*
* Capability-probe helpers. These let calling code discover what the
* backing kernel driver supports rather than hardcoding assumptions
* about specific decoder hardware.
*/
/*
* Query the metadata of an extended control by CID. Fills *qec on
* success. Returns 0 if the control exists, -1 (errno=EINVAL) if the
* driver does not expose this CID. Pass qec=NULL to test existence
* only.
*/
struct v4l2_query_ext_ctrl;
int v4l2_query_ext_ctrl(int video_fd, unsigned int id,
struct v4l2_query_ext_ctrl *qec);
/*
* Query a single menu item of a menu/intmenu control at the given
* index. Fills *qm on success. Returns 0 if the menu item exists at
* this index, -1 otherwise.
*/
struct v4l2_querymenu;
int v4l2_query_menu(int video_fd, unsigned int id, unsigned int index,
struct v4l2_querymenu *qm);
/*
* Convenience: for a menu-type control, return true iff `value` is a
* valid menu entry (i.e. the driver accepts it). Walks all menu items
* up to the control's maximum to check.
*/
bool v4l2_ctrl_menu_has_value(int video_fd, unsigned int id,
unsigned int value);
#endif