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/*
* V4L2 context helper functions.
*
* Copyright (C) 2017 Alexis Ballier <aballier@gentoo.org>
* Copyright (C) 2017 Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_V4L2_CONTEXT_H
#define AVCODEC_V4L2_CONTEXT_H
#include <stdatomic.h>
#include <linux/videodev2.h>
#include "libavcodec/avcodec.h"
#include "libavutil/pixfmt.h"
#include "libavutil/frame.h"
#include "libavutil/buffer.h"
#include "v4l2_buffers.h"
typedef struct V4L2Context {
/**
* context name.
*/
const char* name;
/**
* Type of this buffer context.
* See V4L2_BUF_TYPE_VIDEO_* in videodev2.h
* Readonly after init.
*/
enum v4l2_buf_type type;
/**
* AVPixelFormat corresponding to this buffer context.
* AV_PIX_FMT_NONE means this is an encoded stream.
*/
enum AVPixelFormat av_pix_fmt;
/**
* AVCodecID corresponding to this buffer context.
* AV_CODEC_ID_RAWVIDEO means this is a raw stream and av_pix_fmt must be set to a valid value.
*/
enum AVCodecID av_codec_id;
/**
* Format returned by the driver after initializing the buffer context.
* Readonly after init.
*/
struct v4l2_format format;
/**
* Width and height of the frames it produces (in case of a capture context, e.g. when decoding)
* or accepts (in case of an output context, e.g. when encoding).
*/
int width, height;
/**
* Indexed array of V4L2Buffers
*/
V4L2Buffer *buffers;
/**
* Readonly after init.
*/
int num_buffers;
/**
* Whether the stream has been started (VIDIOC_STREAMON has been sent).
*/
int streamon;
/**
* Either no more buffers available or an unrecoverable error was notified
* by the V4L2 kernel driver: once set the context has to be exited.
*/
int done;
} V4L2Context;
/**
* Initializes a V4L2Context.
*
* @param[in] ctx A pointer to a V4L2Context. See V4L2Context description for required variables.
* @return 0 in case of success, a negative value representing the error otherwise.
*/
int ff_v4l2_context_init(V4L2Context* ctx);
/**
* Sets the V4L2Context format in the v4l2 driver.
*
* @param[in] ctx A pointer to a V4L2Context. See V4L2Context description for required variables.
* @return 0 in case of success, a negative value representing the error otherwise.
*/
int ff_v4l2_context_set_format(V4L2Context* ctx);
/**
* Queries the driver for a valid v4l2 format and copies it to the context.
*
* @param[in] ctx A pointer to a V4L2Context. See V4L2Context description for required variables.
* @param[in] probe Probe only and ignore changes to the format.
* @return 0 in case of success, a negative value representing the error otherwise.
*/
int ff_v4l2_context_get_format(V4L2Context* ctx, int probe);
/**
* Releases a V4L2Context.
*
* @param[in] ctx A pointer to a V4L2Context.
* The caller is reponsible for freeing it.
* It must not be used after calling this function.
*/
void ff_v4l2_context_release(V4L2Context* ctx);
/**
* Sets the status of a V4L2Context.
*
* @param[in] ctx A pointer to a V4L2Context.
* @param[in] cmd The status to set (VIDIOC_STREAMON or VIDIOC_STREAMOFF).
* Warning: If VIDIOC_STREAMOFF is sent to a buffer context that still has some frames buffered,
* those frames will be dropped.
* @return 0 in case of success, a negative value representing the error otherwise.
*/
int ff_v4l2_context_set_status(V4L2Context* ctx, uint32_t cmd);
/**
* Dequeues a buffer from a V4L2Context to an AVPacket.
*
* The pkt must be non NULL.
* @param[in] ctx The V4L2Context to dequeue from.
* @param[inout] pkt The AVPacket to dequeue to.
* @return 0 in case of success, AVERROR(EAGAIN) if no buffer was ready, another negative error in case of error.
*/
int ff_v4l2_context_dequeue_packet(V4L2Context* ctx, AVPacket* pkt);
/**
* Dequeues a buffer from a V4L2Context to an AVFrame.
*
* The frame must be non NULL.
* @param[in] ctx The V4L2Context to dequeue from.
* @param[inout] f The AVFrame to dequeue to.
* @return 0 in case of success, AVERROR(EAGAIN) if no buffer was ready, another negative error in case of error.
*/
int ff_v4l2_context_dequeue_frame(V4L2Context* ctx, AVFrame* f);
/**
* Enqueues a buffer to a V4L2Context from an AVPacket
*
* The packet must be non NULL.
* When the size of the pkt is null, the buffer is not queued but a V4L2_DEC_CMD_STOP command is sent instead to the driver.
*
* @param[in] ctx The V4L2Context to enqueue to.
* @param[in] pkt A pointer to an AVPacket.
* @return 0 in case of success, a negative error otherwise.
*/
int ff_v4l2_context_enqueue_packet(V4L2Context* ctx, const AVPacket* pkt);
/**
* Enqueues a buffer to a V4L2Context from an AVFrame
*
* The frame must be non NULL.
*
* @param[in] ctx The V4L2Context to enqueue to.
* @param[in] f A pointer to an AVFrame to enqueue.
* @return 0 in case of success, a negative error otherwise.
*/
int ff_v4l2_context_enqueue_frame(V4L2Context* ctx, const AVFrame* f);
#endif // AVCODEC_V4L2_CONTEXT_H
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