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