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leandromoreiraleandromoreira
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Merge pull request #35 from leandromoreira/remuxing-chapter
Remuxing chapter
2 parents 6563e98 + 3f44f07 commit 5e7e141

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‎2_remuxing.c‎

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// based on https://ffmpeg.org/doxygen/trunk/remuxing_8c-example.html
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#include <libavutil/timestamp.h>
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#include <libavformat/avformat.h>
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int main(int argc, char **argv)
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{
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AVFormatContext *input_format_context = NULL, *output_format_context = NULL;
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AVPacket packet;
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const char *in_filename, *out_filename;
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int ret, i;
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int stream_index = 0;
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int *streams_list = NULL;
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int number_of_streams = 0;
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int fragmented_mp4_options = 0;
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if (argc < 3) {
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printf("You need to pass at least two parameters.\n");
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return -1;
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} else if (argc == 4) {
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fragmented_mp4_options = 1;
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}
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in_filename = argv[1];
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out_filename = argv[2];
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if ((ret = avformat_open_input(&input_format_context, in_filename, NULL, NULL)) < 0) {
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fprintf(stderr, "Could not open input file '%s'", in_filename);
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goto end;
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}
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if ((ret = avformat_find_stream_info(input_format_context, NULL)) < 0) {
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fprintf(stderr, "Failed to retrieve input stream information");
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goto end;
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}
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avformat_alloc_output_context2(&output_format_context, NULL, NULL, out_filename);
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if (!output_format_context) {
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fprintf(stderr, "Could not create output context\n");
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ret = AVERROR_UNKNOWN;
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goto end;
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}
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number_of_streams = input_format_context->nb_streams;
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streams_list = av_mallocz_array(number_of_streams, sizeof(*streams_list));
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if (!streams_list) {
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ret = AVERROR(ENOMEM);
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goto end;
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}
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for (i = 0; i < input_format_context->nb_streams; i++) {
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AVStream *out_stream;
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AVStream *in_stream = input_format_context->streams[i];
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AVCodecParameters *in_codecpar = in_stream->codecpar;
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if (in_codecpar->codec_type != AVMEDIA_TYPE_AUDIO &&
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in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO &&
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in_codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
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streams_list[i] = -1;
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continue;
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}
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streams_list[i] = stream_index++;
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out_stream = avformat_new_stream(output_format_context, NULL);
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if (!out_stream) {
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fprintf(stderr, "Failed allocating output stream\n");
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ret = AVERROR_UNKNOWN;
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goto end;
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}
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ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
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if (ret < 0) {
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fprintf(stderr, "Failed to copy codec parameters\n");
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goto end;
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}
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}
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// https://ffmpeg.org/doxygen/trunk/group__lavf__misc.html#gae2645941f2dc779c307eb6314fd39f10
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av_dump_format(output_format_context, 0, out_filename, 1);
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// unless it's a no file (we'll talk later about that) write to the disk (FLAG_WRITE)
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// but basically it's a way to save the file to a buffer so you can store it
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// wherever you want.
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if (!(output_format_context->oformat->flags & AVFMT_NOFILE)) {
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ret = avio_open(&output_format_context->pb, out_filename, AVIO_FLAG_WRITE);
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if (ret < 0) {
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fprintf(stderr, "Could not open output file '%s'", out_filename);
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goto end;
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}
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}
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AVDictionary* opts = NULL;
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if (fragmented_mp4_options) {
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// https://developer.mozilla.org/en-US/docs/Web/API/Media_Source_Extensions_API/Transcoding_assets_for_MSE
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av_dict_set(&opts, "movflags", "frag_keyframe+empty_moov+default_base_moof", 0);
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}
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// https://ffmpeg.org/doxygen/trunk/group__lavf__encoding.html#ga18b7b10bb5b94c4842de18166bc677cb
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ret = avformat_write_header(output_format_context, &opts);
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if (ret < 0) {
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fprintf(stderr, "Error occurred when opening output file\n");
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goto end;
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}
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while (1) {
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AVStream *in_stream, *out_stream;
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ret = av_read_frame(input_format_context, &packet);
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if (ret < 0)
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break;
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in_stream = input_format_context->streams[packet.stream_index];
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if (packet.stream_index >= number_of_streams || streams_list[packet.stream_index] < 0) {
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av_packet_unref(&packet);
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continue;
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}
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packet.stream_index = streams_list[packet.stream_index];
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out_stream = output_format_context->streams[packet.stream_index];
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/* copy packet */
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packet.pts = av_rescale_q_rnd(packet.pts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);
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packet.dts = av_rescale_q_rnd(packet.dts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);
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packet.duration = av_rescale_q(packet.duration, in_stream->time_base, out_stream->time_base);
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// https://ffmpeg.org/doxygen/trunk/structAVPacket.html#ab5793d8195cf4789dfb3913b7a693903
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packet.pos = -1;
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//https://ffmpeg.org/doxygen/trunk/group__lavf__encoding.html#ga37352ed2c63493c38219d935e71db6c1
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ret = av_interleaved_write_frame(output_format_context, &packet);
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if (ret < 0) {
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fprintf(stderr, "Error muxing packet\n");
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break;
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}
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av_packet_unref(&packet);
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}
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//https://ffmpeg.org/doxygen/trunk/group__lavf__encoding.html#ga7f14007e7dc8f481f054b21614dfec13
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av_write_trailer(output_format_context);
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end:
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avformat_close_input(&input_format_context);
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/* close output */
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if (output_format_context && !(output_format_context->oformat->flags & AVFMT_NOFILE))
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avio_closep(&output_format_context->pb);
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avformat_free_context(output_format_context);
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av_freep(&streams_list);
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if (ret < 0 && ret != AVERROR_EOF) {
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fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
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return 1;
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}
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return 0;
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}
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‎Makefile‎

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@@ -9,3 +9,15 @@ make_hello: clean
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run_hello: make_hello
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docker run -w /files --rm -it -v `pwd`:/files leandromoreira/ffmpeg-devel /files/build/hello /files/small_bunny_1080p_60fps.mp4
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make_remuxing: clean
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docker run -w /files --rm -it -v `pwd`:/files leandromoreira/ffmpeg-devel \
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gcc -L/opt/ffmpeg/lib -I/opt/ffmpeg/include/ /files/2_remuxing.c \
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-lavcodec -lavformat -lavfilter -lavdevice -lswresample -lswscale -lavutil \
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-o /files/build/remuxing
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run_remuxing_ts: make_remuxing
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docker run -w /files --rm -it -v `pwd`:/files leandromoreira/ffmpeg-devel /files/build/remuxing /files/small_bunny_1080p_60fps.mp4 /files/remuxed_small_bunny_1080p_60fps.ts
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run_remuxing_fragmented_mp4: make_remuxing
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docker run -w /files --rm -it -v `pwd`:/files leandromoreira/ffmpeg-devel /files/build/remuxing /files/small_bunny_1080p_60fps.mp4 /files/fragmented_small_bunny_1080p_60fps.mp4 fragmented

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