[FFmpeg-devel] [PATCH V2] example/vaapi_transcode: Add a VA-API transcode example.
Mark Thompson
sw at jkqxz.net
Mon Jan 29 01:18:41 EET 2018
On 26/01/18 13:11, Jun Zhao wrote:
> V2: - deduce output format from file extension, because VP8/VP9 encoder
> need to a muxer (e,g ivf or/and mp4).
>
> From 9828a8889d5279202c2e8ef9429eb06ad869842b Mon Sep 17 00:00:00 2001
> From: Jun Zhao <jun.zhao at intel.com>
> Date: Thu, 11 Jan 2018 15:00:30 +0800
> Subject: [PATCH V2] example/vaapi_transcode: Add a VA-API transcode example.
>
> Add VA-API transcoding example, useage like:
> ./vaapi_transcode input_stream h264_vaapi output_stream,
> and the example can't handle resolution change case.
>
> test case like:
> - ./vaapi_transcode input.mp4 h264_vaapi output_h264.mp4
> - ./vaapi_transcode input.mp4 vp8_vaapi output_vp8.ivf
>
> Signed-off-by: Jun Zhao <jun.zhao at intel.com>
> Signed-off-by: Liu, Kaixuan <kaixuan.liu at intel.com>
> ---
> configure | 2 +
> doc/examples/Makefile | 1 +
> doc/examples/vaapi_transcode.c | 301 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 304 insertions(+)
> create mode 100644 doc/examples/vaapi_transcode.c
Generally looks good, some minor things below.
Thanks,
- Mark
> diff --git a/configure b/configure
> index fcfa7aa442..92aef31cbe 100755
> --- a/configure
> +++ b/configure
> @@ -1526,6 +1526,7 @@ EXAMPLE_LIST="
> transcode_aac_example
> transcoding_example
> vaapi_encode_example
> + vaapi_transcode_example
> "
>
> EXTERNAL_AUTODETECT_LIBRARY_LIST="
> @@ -3320,6 +3321,7 @@ scaling_video_example_deps="avutil swscale"
> transcode_aac_example_deps="avcodec avformat swresample"
> transcoding_example_deps="avfilter avcodec avformat avutil"
> vaapi_encode_example_deps="avcodec avutil h264_vaapi_encoder"
> +vaapi_transcode_example_deps="avcodec avformat avutil"
Should probably depend on something VAAPI? It will build fine without it, but can't actually work at all.
>
> # EXTRALIBS_LIST
> cpu_init_extralibs="pthreads_extralibs"
> diff --git a/doc/examples/Makefile b/doc/examples/Makefile
> index da5af36532..928ff306b3 100644
> --- a/doc/examples/Makefile
> +++ b/doc/examples/Makefile
> @@ -20,6 +20,7 @@ EXAMPLES-$(CONFIG_SCALING_VIDEO_EXAMPLE) += scaling_video
> EXAMPLES-$(CONFIG_TRANSCODE_AAC_EXAMPLE) += transcode_aac
> EXAMPLES-$(CONFIG_TRANSCODING_EXAMPLE) += transcoding
> EXAMPLES-$(CONFIG_VAAPI_ENCODE_EXAMPLE) += vaapi_encode
> +EXAMPLES-$(CONFIG_VAAPI_TRANSCODE_EXAMPLE) += vaapi_transcode
>
> EXAMPLES := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)$(EXESUF))
> EXAMPLES_G := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)_g$(EXESUF))
> diff --git a/doc/examples/vaapi_transcode.c b/doc/examples/vaapi_transcode.c
> new file mode 100644
> index 0000000000..af1550f5f2
> --- /dev/null
> +++ b/doc/examples/vaapi_transcode.c
> @@ -0,0 +1,301 @@
> +/*
> + * Video Acceleration API (video transcoding) transcode 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
> + * Intel VAAPI-accelerated transcoding example.
> + *
> + * @example vaapi_transcode.c
> + * This example shows how to do VAAPI-accelerated transcoding.
> + * Usage: vaapi_transcode input_stream h264_vaapi output_stream
> + * e.g: - vaapi_transcode input.mp4 h264_vaapi output_h264.mp4
> + * - vaapi_transcode input.mp4 vp9_vaapi output_vp9.ivf
> + */
> +
> +#include <stdio.h>
> +#include <errno.h>
> +
> +#include <libavutil/hwcontext.h>
> +#include <libavcodec/avcodec.h>
> +#include <libavformat/avformat.h>
> +
> +static AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
> +static AVBufferRef *hw_device_ctx = NULL;
> +static AVCodecContext *decoder_ctx = NULL, *encoder_ctx = NULL;
> +static int video_stream = -1;
> +static AVStream *ost;
> +static int initialized = 0;
> +
> +static enum AVPixelFormat get_vaapi_format(AVCodecContext *ctx,
> + const enum AVPixelFormat *pix_fmts)
> +{
> + const enum AVPixelFormat *p;
> +
> + for (p = pix_fmts; *p != AV_PIX_FMT_NONE; p++) {
> + if (*p == AV_PIX_FMT_VAAPI)
> + return *p;
> + }
> +
> + fprintf(stderr, "Unable to decode this file using VA-API.\n");
> + return AV_PIX_FMT_NONE;
> +}
> +
> +static int open_input_file(const char *filename)
> +{
> + int ret;
> + AVCodec *decoder = NULL;
> + AVStream *video = NULL;
> +
> + if ((ret = avformat_open_input(&ifmt_ctx, filename, NULL, NULL)) < 0) {
> + fprintf(stderr, "Cannot open input file '%s', Error code: %s\n",
> + filename, av_err2str(ret));
> + return ret;
> + }
> +
> + if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) {
> + fprintf(stderr, "Cannot find input stream information. Error code: %s\n",
> + av_err2str(ret));
> + return ret;
> + }
> +
> + ret = av_find_best_stream(ifmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
> + if (ret < 0) {
> + fprintf(stderr, "Cannot find a video stream in the input file. "
> + "Error code: %s\n", av_err2str(ret));
> + return ret;
> + }
> + video_stream = ret;
> +
> + if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
> + return AVERROR(ENOMEM);
> +
> + video = ifmt_ctx->streams[video_stream];
> + if ((ret = avcodec_parameters_to_context(decoder_ctx, video->codecpar)) < 0) {
> + fprintf(stderr, "avcodec_parameters_to_context error. Error code: %s\n",
> + av_err2str(ret));
> + return ret;
> + }
> +
> + decoder_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
Missing return value check.
> + decoder_ctx->get_format = get_vaapi_format;
> +
> + if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0)
> + fprintf(stderr, "Failed to open codec for decoding. Error code: %s\n",
> + av_err2str(ret));
> +
> + return ret;
> +}
> +
> +static int encode_write(AVFrame *frame)
> +{
> + int ret = 0;
> + AVPacket enc_pkt;
> +
> + av_init_packet(&enc_pkt);
> + enc_pkt.data = NULL;
> + enc_pkt.size = 0;
> +
> + if ((ret = avcodec_send_frame(encoder_ctx, frame)) < 0) {
> + fprintf(stderr, "Error during encoding. Error code: %s\n", av_err2str(ret));
> + goto end;
> + }
> + while (1) {
> + ret = avcodec_receive_packet(encoder_ctx, &enc_pkt);
> + if (ret)
> + break;
> +
> + enc_pkt.stream_index = 0;
> + av_packet_rescale_ts(&enc_pkt, ifmt_ctx->streams[video_stream]->time_base,
> + ofmt_ctx->streams[0]->time_base);
> + ret = av_interleaved_write_frame(ofmt_ctx, &enc_pkt);
> + if (ret < 0) {
> + fprintf(stderr, "Error during writing data to output file. "
> + "Error code: %s\n", av_err2str(ret));
> + return -1;
> + }
> + }
> +
> +end:
> + if (ret == AVERROR_EOF)
> + return 0;
> + ret = ((ret == AVERROR(EAGAIN)) ? 0:-1);
> + return ret;
> +}
> +
> +static int dec_enc(AVPacket *pkt, AVCodec *enc_codec, const char *file)
> +{
> + AVFrame *frame;
> + int ret = 0;
> +
> + ret = avcodec_send_packet(decoder_ctx, pkt);
> + if (ret < 0) {
> + fprintf(stderr, "Error during decoding. Error code: %s\n", av_err2str(ret));
> + return ret;
> + }
> +
> + while (ret >= 0) {
> + if (!(frame = av_frame_alloc()))
> + return AVERROR(ENOMEM);
> +
> + ret = avcodec_receive_frame(decoder_ctx, frame);
> + if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
> + av_frame_free(&frame);
> + return 0;
> + } else if (ret < 0) {
> + fprintf(stderr, "Error while decoding. Error code: %s\n", av_err2str(ret));
> + goto fail;
> + }
> +
> + if (!initialized) {
> + /* we need to ref hw_frames_ctx of decoder to initialize encoder's codec.
> + Only after we get a decoded frame, can we obtain its hw_frames_ctx */
> + encoder_ctx->hw_frames_ctx = av_buffer_ref(decoder_ctx->hw_frames_ctx);
> + if (!encoder_ctx->hw_frames_ctx) {
> + ret = AVERROR(ENOMEM);
> + goto fail;
> + }
> + /* set AVCodecContext Parameters for encoder, here we keep them stay
> + * the same as decoder.
> + * xxx: now the the sample can't handle resolution change case.
> + */
> + encoder_ctx->time_base = av_inv_q(decoder_ctx->framerate);
> + encoder_ctx->pix_fmt = AV_PIX_FMT_VAAPI;
> + encoder_ctx->width = decoder_ctx->width;
> + encoder_ctx->height = decoder_ctx->height;
> +
> + if ((ret = avcodec_open2(encoder_ctx, enc_codec, NULL)) < 0) {
> + fprintf(stderr, "Failed to open encode codec. Error code: %s\n",
> + av_err2str(ret));
> + goto fail;
> + }
> +
> + if (!(ost = avformat_new_stream(ofmt_ctx, enc_codec))) {
> + fprintf(stderr, "Failed to allocate stream for output format.\n");
> + ret = AVERROR(ENOMEM);
> + goto fail;
> + }
> +
> + ost->time_base = encoder_ctx->time_base;
> + ret = avcodec_parameters_from_context(ost->codecpar, encoder_ctx);
> + if (ret < 0) {
> + fprintf(stderr, "Failed to copy the stream parameters. "
> + "Error code: %s\n", av_err2str(ret));
> + goto fail;
> + }
> +
> + ret = avio_open(&ofmt_ctx->pb, file, AVIO_FLAG_WRITE);
> + if (ret < 0) {
> + fprintf(stderr, "Cannot open output file. "
> + "Error code: %s\n", av_err2str(ret));
> + goto fail;
> + }
> +
> + /* write the stream header */
> + if ((ret = avformat_write_header(ofmt_ctx, NULL)) < 0) {
> + fprintf(stderr, "Error while writing stream header. "
> + "Error code: %s\n", av_err2str(ret));
> + goto fail;
> + }
> +
> + initialized = 1;
> + }
> +
> + if ((ret = encode_write(frame)) < 0)
> + fprintf(stderr, "Error during encoding and writing.\n");
> +
> +fail:
> + av_frame_free(&frame);
> + if (ret < 0)
> + return ret;
> + }
> + return 0;
> +}
> +
> +int main(int argc, char **argv) {
> + int ret = 0;
> + AVPacket dec_pkt;
> + AVCodec *enc_codec;
> +
> + if (argc != 4) {
> + fprintf(stderr, "Usage: %s <input file> <encode codec> <output file>\n"
> + "The output format is guessed according to the file extension.\n"
> + "\n", argv[0]);
> + return -1;
> + }
> +
> + av_register_all();
> +
> + ret = av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, NULL, NULL, 0);
> + if (ret < 0) {
> + fprintf(stderr, "Failed to create a VAAPI device. Error code: %s\n", av_err2str(ret));
> + return -1;
> + }
> +
> + if ((ret = open_input_file(argv[1])) < 0)
> + goto end;
> +
> + if (!(enc_codec = avcodec_find_encoder_by_name(argv[2]))) {
> + fprintf(stderr, "Could not find encoder '%s'\n", argv[2]);
> + ret = -1;
> + goto end;
> + }
> +
> + if ((ret = (avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, argv[3]))) < 0) {
> + fprintf(stderr, "Failed to deduce output format from file extension. Error code: "
> + "%s\n", av_err2str(ret));
> + goto end;
> + }
> +
> + if (!(encoder_ctx = avcodec_alloc_context3(enc_codec))) {
> + ret = AVERROR(ENOMEM);
> + goto end;
> + }
> +
> + /* read all packets and only transcoding video */
> + while (ret >= 0) {
> + if ((ret = av_read_frame(ifmt_ctx, &dec_pkt)) < 0)
> + break;
> +
> + if (video_stream == dec_pkt.stream_index)
> + ret = dec_enc(&dec_pkt, enc_codec, argv[3]);
> +
> + av_packet_unref(&dec_pkt);
> + }
> +
> + /* flush decoder */
> + dec_pkt.data = NULL;
> + dec_pkt.size = 0;
> + ret = dec_enc(&dec_pkt, enc_codec, argv[3]);
> + av_packet_unref(&dec_pkt);
> +
> + /* flush encoder */
> + ret = encode_write(NULL);
> +
> + /* write the trailer for output stream */
> + av_write_trailer(ofmt_ctx);
This encode/write step shouldn't be called if the output hasn't been opened. For example, if you give it a file which is valid but can't be decoded with VAAPI then you get a segfault here.
> +
> +end:
> + avformat_close_input(&ifmt_ctx);
> + avformat_close_input(&ofmt_ctx);
> + avcodec_free_context(&decoder_ctx);
> + avcodec_free_context(&encoder_ctx);
> + av_buffer_unref(&hw_device_ctx);
> + return ret;
> +}
> --
> 2.14.1
>
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