[FFmpeg-devel] [PATCH] Add example reencoding_filtered_video.c
Lukasz Marek
lukasz.m.luki at gmail.com
Thu Jan 30 20:40:15 CET 2014
On 30.01.2014 20:07, Andrey Utkin wrote:
> ---
> configure | 2 +
> doc/Makefile | 1 +
> doc/examples/Makefile | 1 +
> doc/examples/reencoding_filtered_video.c | 409 +++++++++++++++++++++++++++++++
> 4 files changed, 413 insertions(+)
> create mode 100644 doc/examples/reencoding_filtered_video.c
>
> diff --git a/configure b/configure
> index 0fbaa6a..40dab3d 100755
> --- a/configure
> +++ b/configure
> @@ -1247,6 +1247,7 @@ EXAMPLE_LIST="
> filtering_video_example
> metadata_example
> muxing_example
> + reencoding_filtered_video_example
> remuxing_example
> resampling_audio_example
> scaling_video_example
> @@ -2396,6 +2397,7 @@ filtering_audio_example_deps="avfilter avcodec avformat avutil"
> filtering_video_example_deps="avfilter avcodec avformat avutil"
> metadata_example_deps="avformat avutil"
> muxing_example_deps="avcodec avformat avutil swscale"
> +reencoding_filtered_video_example_deps="avfilter avcodec avformat avutil"
> remuxing_example_deps="avcodec avformat avutil"
> resampling_audio_example_deps="avutil swresample"
> scaling_video_example_deps="avutil swscale"
> diff --git a/doc/Makefile b/doc/Makefile
> index 4092f52..f6cd2d8 100644
> --- a/doc/Makefile
> +++ b/doc/Makefile
> @@ -42,6 +42,7 @@ DOC_EXAMPLES-$(CONFIG_FILTERING_AUDIO_EXAMPLE) += filtering_audio
> DOC_EXAMPLES-$(CONFIG_FILTERING_VIDEO_EXAMPLE) += filtering_video
> DOC_EXAMPLES-$(CONFIG_METADATA_EXAMPLE) += metadata
> DOC_EXAMPLES-$(CONFIG_MUXING_EXAMPLE) += muxing
> +DOC_EXAMPLES-$(CONFIG_REENCODING_FILTERED_VIDEO_EXAMPLE) += reencoding_filtered_video
> DOC_EXAMPLES-$(CONFIG_REMUXING_EXAMPLE) += remuxing
> DOC_EXAMPLES-$(CONFIG_RESAMPLING_AUDIO_EXAMPLE) += resampling_audio
> DOC_EXAMPLES-$(CONFIG_SCALING_VIDEO_EXAMPLE) += scaling_video
> diff --git a/doc/examples/Makefile b/doc/examples/Makefile
> index a25455e..900b8c3 100644
> --- a/doc/examples/Makefile
> +++ b/doc/examples/Makefile
> @@ -17,6 +17,7 @@ EXAMPLES= decoding_encoding \
> filtering_audio \
> metadata \
> muxing \
> + reencoding_filtered_video \
> remuxing \
> resampling_audio \
> scaling_video \
> diff --git a/doc/examples/reencoding_filtered_video.c b/doc/examples/reencoding_filtered_video.c
> new file mode 100644
> index 0000000..a4acd46
> --- /dev/null
> +++ b/doc/examples/reencoding_filtered_video.c
> @@ -0,0 +1,409 @@
> +/*
> + * Copyright (c) 2010 Nicolas George
> + * Copyright (c) 2011 Stefano Sabatini
> + * Copyright (c) 2014 Andrey Utkin
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +/**
> + * @file
> + * API example for demuxing, decoding, filtering, encoding and muxing
> + * @example doc/examples/reencoding_filtered_video.c
> + */
> +
> +#include <assert.h>
> +
> +#include <libavcodec/avcodec.h>
> +#include <libavformat/avformat.h>
> +#include <libavfilter/avfiltergraph.h>
> +#include <libavfilter/avcodec.h>
> +#include <libavfilter/buffersink.h>
> +#include <libavfilter/buffersrc.h>
> +#include <libavutil/opt.h>
> +#include <libavutil/pixdesc.h>
> +
> +/* Filtergraph string is a good place to set up resize, pixel/sample format or
> + * timebase conversion, constant output fps etc.
> + */
> +const char *filter_descr;
> +
> +static AVFormatContext *ifmt_ctx;
> +static AVFormatContext *ofmt_ctx;
> +static AVCodecContext *dec_ctx;
> +static AVCodecContext *enc_ctx;
> +AVFilterContext *buffersink_ctx;
> +AVFilterContext *buffersrc_ctx;
> +AVFilterGraph *filter_graph;
> +static int video_stream_index = -1;
> +
> +static int open_input_file(const char *filename)
> +{
> + int ret;
> +
> + ifmt_ctx = NULL;
> + if ((ret = avformat_open_input(&ifmt_ctx, filename, NULL, NULL)) < 0) {
> + av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");
> + return ret;
> + }
> +
> + if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) {
> + av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");
> + return ret;
> + }
> +
> + /* select the video stream */
> + ret = av_find_best_stream(ifmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
> + if (ret < 0) {
> + av_log(NULL, AV_LOG_ERROR, "Cannot find a video stream in the input file\n");
> + return ret;
> + }
> + video_stream_index = ret;
> + dec_ctx = ifmt_ctx->streams[video_stream_index]->codec;
> + av_opt_set_int(dec_ctx, "refcounted_frames", 1, 0);
> +
> + av_dump_format(ifmt_ctx, 0, filename, 0);
> + return 0;
> +}
> +
> +static int open_output_file(const char *filename)
> +{
> + AVStream *out_stream;
> + AVCodec *enc;
> + AVDictionary *encoder_opts = NULL;
> + int ret;
> +
> + ofmt_ctx = NULL;
> + avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, filename);
> + if (!ofmt_ctx) {
> + fprintf(stderr, "Could not create output context\n");
It is inconsistent with av_log(NULL, AV_LOG_ERROR, used above
> + ret = AVERROR_UNKNOWN;
> + return ret;
> + }
> +
> + /* Open just one elementary stream for transcoded video */
> + enc = avcodec_find_encoder(AV_CODEC_ID_H264);
> +
> + out_stream = avformat_new_stream(ofmt_ctx, enc);
> + if (!out_stream) {
> + fprintf(stderr, "Failed allocating output stream\n");
> + ret = AVERROR_UNKNOWN;
> + return ret;
return AVERROR_UNKNOWN;
> + }
> +
> + if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
> + out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
> +
> + /* rewrite output codec setting according to our needs */
> + /* in this example, we choose transcoding to H264 */
> +
> + /* init the video decoder */
> + if ((ret = avcodec_open2(dec_ctx, avcodec_find_decoder(dec_ctx->codec_id), NULL)) < 0) {
> + av_log(NULL, AV_LOG_ERROR, "Cannot open video decoder\n");
> + return ret;
> + }
> +
> + /* init the video encoder */
> + enc_ctx = out_stream->codec;
> + enc_ctx->height = dec_ctx->height;
> + enc_ctx->width = dec_ctx->width;
> + /* yuv420p is just common in use and known to be supported by libx264
> + * pix_fmt can be also taken from enc->pix_fmts[]
> + */
> + enc_ctx->pix_fmt = AV_PIX_FMT_YUV420P;
> + enc_ctx->time_base = out_stream->time_base;
> + av_dict_set(&encoder_opts, "preset", "medium", 0); /* performance/quality high-level configuration */
> + av_dict_set(&encoder_opts, "profile", "baseline", 0); /* H264 specific profile */
> + if ((ret = avcodec_open2(enc_ctx, enc, &encoder_opts)) < 0) {
> + av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder\n");
> + return ret;
> + }
> + av_dump_format(ofmt_ctx, 0, filename, 1);
> +
> + if (!(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) {
> + ret = avio_open(&ofmt_ctx->pb, filename, AVIO_FLAG_WRITE);
> + if (ret < 0) {
> + fprintf(stderr, "Could not open output file '%s'", filename);
> + return ret;
> + }
> + }
> +
> + /* init muxer, write output file header */
> + ret = avformat_write_header(ofmt_ctx, NULL);
> + if (ret < 0) {
> + fprintf(stderr, "Error occurred when opening output file\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int init_filters(const char *filters_descr)
> +{
> + char args[512];
> + int ret = 0;
> + AVFilter *buffersrc = avfilter_get_by_name("buffer");
> + AVFilter *buffersink = avfilter_get_by_name("buffersink");
> + AVFilterInOut *outputs = avfilter_inout_alloc();
> + AVFilterInOut *inputs = avfilter_inout_alloc();
> +
> + filter_graph = avfilter_graph_alloc();
> +
> + assert(buffersrc && buffersink && outputs && inputs && filter_graph);
I thing returning AVERROR(ENOMEM) is more accurate.
--
Best Regards,
Lukasz Marek
If you can't explain it simply, you don't understand it well enough. -
Albert Einstein
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