[FFmpeg-devel] [PATCH 2/2] example/vaapi_transcode: Add a VA-API transcode example.
Mark Thompson
sw at jkqxz.net
Fri Jan 19 03:45:14 EET 2018
On 11/01/18 07:07, Jun Zhao wrote:
> From b76a2f790814df326d7d93c54b14b3c8e74ab759 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 2/2] example/vaapi_transcode: Add a VA-API transcode example.
>
> Add VA-API transcoding example, useage like:
> ./vaapi_transcode input_stream h264_vaapi output_stream
>
> 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 | 256 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 259 insertions(+)
> create mode 100644 doc/examples/vaapi_transcode.c
>
> diff --git a/configure b/configure
> index b8985ba542..6d08c0fbbb 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="
> @@ -3319,6 +3320,7 @@ 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"
> +vaapi_transcode_example_deps="avcodec avformat avutil"
>
> # 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..b92a387f2f
> --- /dev/null
> +++ b/doc/examples/vaapi_transcode.c
> @@ -0,0 +1,256 @@
> +/*
> + * 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
> + */
> +
> +#include <stdio.h>
> +#include <libavcodec/avcodec.h>
> +#include <libavformat/avformat.h>
> +#include <libavutil/hwcontext.h>
> +#include <libavutil/avassert.h>
> +#include <errno.h>
> +
> +static AVFormatContext *ifmt_ctx = NULL;
> +static AVBufferRef *hw_device_ctx = NULL;
> +static AVCodecContext *decoder_ctx = NULL, *encoder_ctx = NULL;
> +static int video_stream = -1;
> +static FILE *fout;
> +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 != -1; p++) {
AV_PIX_FMT_NONE would be clearer than -1 here.
> + if (*p == AV_PIX_FMT_VAAPI)
> + return *p;
> + }
> +
> + fprintf(stderr, "Failed to get vaapi pix format\n");
Maybe something like "Unable to decode this file using VAAPI", since that's what it actually means (the decoder didn't offer the VAAPI output format).
> + 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));
Use multiple string constants ("foo" "bar") rather than continuation escapes - this is putting a lot of spaces in the middle of the message.
> + 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);
> + 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;
> + ret = fwrite(enc_pkt.data, 1, enc_pkt.size, fout);
fwrite() can fail (returning zero).
> + }
> +
> +end:
> + if (ret == AVERROR_EOF)
> + return 0;
> + ret = ((ret == AVERROR(EAGAIN)) ? 0:-1);
> + return ret;
> +}
> +
> +static int dec_enc(AVPacket *pkt, AVCodec *enc_codec)
> +{
> + 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) {
> + /* Here 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;
> + }
> + if ((ret = avcodec_open2(encoder_ctx, enc_codec, NULL)) < 0) {
> + fprintf(stderr, "Error while open encode codec. 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", 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 (!(fout = fopen(argv[3], "w+b"))) {
> + fprintf(stderr, "Failed to open output file: %s\n", strerror(errno));
> + ret = -1;
> + goto end;
> + }
> +
> + if (!(encoder_ctx= avcodec_alloc_context3(enc_codec))) {
> + ret = AVERROR(ENOMEM);
> + goto end;
> + }
> +
> + /* set AVCodecContext Parameters */
> + encoder_ctx->width = decoder_ctx->width;
> + encoder_ctx->height = decoder_ctx->height;
Not sure you necessarily know this width and height here before the decoder has produced any output? libavformat may have filled this in some cases, but I don't think it has to in all.
> + encoder_ctx->time_base = (AVRational){1, 25};
> + encoder_ctx->pix_fmt = AV_PIX_FMT_VAAPI;
> +
> + /* 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);
> +
> + av_packet_unref(&dec_pkt);
> + }
> +
> + /* flush decoder */
> + dec_pkt.data = NULL;
> + dec_pkt.size = 0;
> + ret = dec_enc(&dec_pkt, enc_codec);
> + av_packet_unref(&dec_pkt);
> +
> + /* flush encoder */
> + ret = encode_write(NULL);
> +
> +end:
> + avformat_close_input(&ifmt_ctx);
> + if (fout)
> + fclose(fout);
> + avcodec_free_context(&decoder_ctx);
> + avcodec_free_context(&encoder_ctx);
> + av_buffer_unref(&hw_device_ctx);
> + return ret;
> +}
> --
> 2.14.1
>
Generally looks fine, and tested a bit.
Probably ignorable, but I note it doesn't produce a usable stream for VP8/VP9 because they don't support raw streams like this.
Thanks,
- Mark
More information about the ffmpeg-devel
mailing list