[FFmpeg-devel] [PATCH V3] examples/hw_decode: Add a HWAccel decoding example.
Jun Zhao
mypopydev at gmail.com
Thu Jul 20 10:09:41 EEST 2017
On 2017/7/20 14:17, Steven Liu wrote:
> 2017-07-20 13:29 GMT+08:00 Jun Zhao <mypopydev at gmail.com>:
>> V3: re-work to support the other hwaccels, just test with vaapi, dxva2|d3d11va|videotoolbox might work as well.
>> V2: re-work with new hw decoding API.
>>
>> _______________________________________________
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>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
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> [FFmpeg-devel] [PATCH V3] examples/hw_decode: Add a HWAccel decoding example.
>
> ffmpeg-devel
> x
>
> Jun Zhao 通过“ffmpeg.org”
>
> 13:29 (41分钟前)
> 发送至 FFmpeg、 Mark、 wm4、 Kaixuan
> 英语
> 中文
>
> 翻译邮件
> 对英语停用
> V3: re-work to support the other hwaccels, just test with vaapi,
> dxva2|d3d11va|videotoolbox might work as well.
> V2: re-work with new hw decoding API.
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
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> 详细信息
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> Zhao Jun
> mypopydev at gmail.com
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> From bd8cbd5c16be3001b950f0c4ae3548909a396bc6 Mon Sep 17 00:00:00 2001
> From: Jun Zhao <jun.zhao at intel.com>
> Date: Thu, 20 Jul 2017 00:58:56 -0400
> Subject: [PATCH V3] examples/hw_decode: Add a HWAccel decoding example.
>
> Add a HWAccel decoding example.
>
> Just test with vaapi, dxva2|d3d11va|videotoolbox might work as well.
>
> Signed-off-by: Liu, Kaixuan <kaixuan.liu at intel.com>
> Signed-off-by: Jun Zhao <jun.zhao at intel.com>
> ---
> doc/examples/hw_decode.c | 246 +++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 246 insertions(+)
> create mode 100644 doc/examples/hw_decode.c
>
> diff --git a/doc/examples/hw_decode.c b/doc/examples/hw_decode.c
> new file mode 100644
> index 0000000000..4070a60cba
> --- /dev/null
> +++ b/doc/examples/hw_decode.c
> @@ -0,0 +1,246 @@
> +/*
> + * Copyright (c) 2017 Jun Zhao
> + * Copyright (c) 2017 Kaixuan Liu
> + *
> + * HW Acceleration API (video decoding) decode sample
> + *
> + * 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
> + */
> +
> +/**
> + * @file
> + * HW-Accelerated decoding example.
> + *
> + * @example hw_decode.c
> + * This example shows how to do HW-accelerated decoding with output
> + * frames from the HW video surfaces.
> + */
> +
> +#include <stdio.h>
> +
> +#include <libavcodec/avcodec.h>
> +#include <libavformat/avformat.h>
> +#include <libavutil/pixdesc.h>
> +#include <libavutil/hwcontext.h>
> +#include <libavutil/opt.h>
> +#include <libavutil/avassert.h>
> +#include <libavutil/imgutils.h>
> +
> +static AVBufferRef *hw_device_ctx = NULL;
> +static enum AVPixelFormat hw_pix_fmt;
> +FILE *output_file = NULL;
> +
> +static enum AVPixelFormat hw_pix_fmts[] = {
> + [AV_HWDEVICE_TYPE_CUDA] = AV_PIX_FMT_CUDA,
> + [AV_HWDEVICE_TYPE_DXVA2] = AV_PIX_FMT_DXVA2_VLD,
> + [AV_HWDEVICE_TYPE_D3D11VA] = AV_PIX_FMT_D3D11VA_VLD,
> + [AV_HWDEVICE_TYPE_QSV] = AV_PIX_FMT_QSV,
> + [AV_HWDEVICE_TYPE_VAAPI] = AV_PIX_FMT_VAAPI,
> + [AV_HWDEVICE_TYPE_VDPAU] = AV_PIX_FMT_VDPAU,
> + [AV_HWDEVICE_TYPE_VIDEOTOOLBOX] = AV_PIX_FMT_VIDEOTOOLBOX,
> +};
> +
> +static enum AVPixelFormat find_fmt_by_hw_type(const enum AVHWDeviceType type)
> +{
> + if (type >= 0 && type < FF_ARRAY_ELEMS(hw_pix_fmts))
> + return hw_pix_fmts[type];
> + else
> + return AV_PIX_FMT_NONE;
> +}
> +
> +static int hw_decoder_init(AVCodecContext *ctx, const enum AVHWDeviceType type)
> +{
> + int err = 0;
> +
> + if ((err = av_hwdevice_ctx_create(&hw_device_ctx, type,
> + NULL, NULL, 0)) < 0) {
> + fprintf(stderr, "Failed to create specified HW device.\n");
> + return err;
> + }
> + ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
> +
> + return err;
> +}
> +
> +static enum AVPixelFormat get_hw_format(AVCodecContext *ctx,
> + const enum AVPixelFormat *pix_fmts)
> +{
> + const enum AVPixelFormat *p;
> +
> + for (p = pix_fmts; *p != -1; p++) {
> + if (*p == hw_pix_fmt)
> + return *p;
> + }
> +
> + fprintf(stderr, "Failed to get HW surface format.\n");
> + return AV_PIX_FMT_NONE;
> +}
> +
> +static int decode_write(AVCodecContext *avctx, AVPacket *packet)
> +{
> + AVFrame *frame = NULL, *sw_frame = NULL;
> + AVFrame *tmp_frame = NULL;
> + uint8_t *buffer = NULL;
> + int size;
> + int ret = 0;
> +
> + ret = avcodec_send_packet(avctx, packet);
> + if (ret < 0) {
> + fprintf(stderr, "Error during decoding\n");
> + return ret;
> + }
> +
> + while (ret >= 0) {
> + if (!(frame = av_frame_alloc()) || !(sw_frame = av_frame_alloc()))
> + return AVERROR(ENOMEM);
> If the frame alloc success and the sw_frame alloc failure, maybe it is memleak?
> or if it is just a sample, that is not the impotant point?
> What about use ret = AVERROR(ENOMEM), goto fail, and add if(frame)
> av_frame_free(&frame);
> if (sw_frame) av_frame_free(&sw_frame);
Good catch, will use goto handle this case, but I think don't need to check NULL before
call av_frame_free, in the function av_frame_free, have handle with if (!frame || !*frame),
so it doesn't need to check the NULL before call av_frame_free.
>
> +
> + ret = avcodec_receive_frame(avctx, frame);
> + if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
> + break;
> + else if (ret < 0) {
> + fprintf(stderr, "Error while decoding\n");
> + goto fail;
> + }
> +
> + if (frame->format == hw_pix_fmt) {
> + /* retrieve data from GPU to CPU */
> + if ((ret = av_hwframe_transfer_data(sw_frame, frame, 0)) < 0) {
> + fprintf(stderr, "Error transferring the data to
> system memory\n");
> + goto fail;
> + }
> + tmp_frame = sw_frame;
> + } else
> + tmp_frame = frame;
> +
> + size = av_image_get_buffer_size(tmp_frame->format, tmp_frame->width,
> + tmp_frame->height, 1);
> + buffer = av_malloc(size);
> + if (!buffer) {
> + fprintf(stderr, "Can not alloc buffer\n");
> + ret = AVERROR(ENOMEM);
> + goto fail;
> + }
> + ret = av_image_copy_to_buffer(buffer, size,
> + (const uint8_t * const *)tmp_frame->data,
> + (const int
> *)tmp_frame->linesize, tmp_frame->format,
> + tmp_frame->width, tmp_frame->height, 1);
> + if (ret < 0) {
> + fprintf(stderr, "Can not copy image to buffer\n");
> + goto fail;
> + }
> +
> + if ((ret = fwrite(buffer, 1, size, output_file)) < 0) {
> + fprintf(stderr, "Failed to dump raw data.\n");
> + goto fail;
> + }
> +
> + fail:
> + av_frame_free(&frame);
> + av_frame_free(&sw_frame);
> + if (buffer)
> + av_freep(&buffer);
> + if (ret < 0)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + AVFormatContext *input_ctx = NULL;
> + int video_stream, ret;
> + AVCodecContext *decoder_ctx = NULL;
> + AVCodec *decoder = NULL;
> + AVPacket packet;
> + enum AVHWDeviceType type;
> +
> + if (argc < 4) {
> + fprintf(stderr, "Usage: %s <vaapi|dxva2|d3d11va> <input file>
> <output file>\n", argv[0]);
> + return -1;
> + }
> +
> + av_register_all();
> +
> + type = av_hwdevice_find_type_by_name(argv[1]);
> + hw_pix_fmt = find_fmt_by_hw_type(type);
> +
> + /* open the input file */
> + if (avformat_open_input(&input_ctx, argv[2], NULL, NULL) != 0) {
> + fprintf(stderr, "Cannot open input file '%s'\n", argv[1]);
> + return -1;
> + }
> +
> + if (avformat_find_stream_info(input_ctx, NULL) < 0) {
> + fprintf(stderr, "Cannot find input stream information.\n");
> + return -1;
> + }
> +
> + /* find the video stream information */
> + ret = av_find_best_stream(input_ctx, AVMEDIA_TYPE_VIDEO, -1, -1,
> &decoder, 0);
> + if (ret < 0) {
> + fprintf(stderr, "Cannot find a video stream in the input file\n");
> + return -1;
> + }
> + video_stream = ret;
> +
> + if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
> + return AVERROR(ENOMEM);
> +
> + AVStream *video = input_ctx->streams[video_stream];
> + if (avcodec_parameters_to_context(decoder_ctx, video->codecpar) < 0)
> + return -1;
> +
> + decoder_ctx->get_format = get_hw_format;
> + av_opt_set_int(decoder_ctx, "refcounted_frames", 1, 0);
> +
> + if (hw_decoder_init(decoder_ctx, type) < 0)
> + return -1;
> +
> + if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0) {
> + fprintf(stderr, "Failed to open codec for stream #%u\n", video_stream);
> + return -1;
> + }
> +
> + /* open the file to dump raw data */
> + output_file = fopen(argv[3], "w+");
> +
> + /* actual decoding and dump the raw data */
> + while (ret >= 0) {
> + if ((ret = av_read_frame(input_ctx, &packet)) < 0)
> + break;
> +
> + if (video_stream == packet.stream_index)
> + ret = decode_write(decoder_ctx, &packet);
> +
> + av_packet_unref(&packet);
> + }
> +
> + /* flush the decoder */
> + packet.data = NULL;
> + packet.size = 0;
> + ret = decode_write(decoder_ctx, &packet);
> + av_packet_unref(&packet);
> +
> + if (output_file)
> + fclose(output_file);
> + avcodec_free_context(&decoder_ctx);
> + avformat_close_input(&input_ctx);
> + av_buffer_unref(&hw_device_ctx);
> +
> + return 0;
> +}
>
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