[Libav-user] Remuxing/Codec copy over rtp_mpegts really bad quality result
Benji Amello
benji.amello at gmail.com
Wed Dec 27 22:12:45 EET 2017
Any help is much appreciated
On Mon, Dec 25, 2017 at 6:13 PM, Benji Amello <benji.amello at gmail.com>
wrote:
> Hi,
>
> I am struggling with issue for past 2 weeks & making almost no progress.
> I am trying to do codec copy of a stream(testing with file & later
> going to use live stream) with format rtp_mpegts over network & play
> using VLC player. Started my proof of concept code with slightly
> modified remuxing.c in the examples.
>
>
> I am essentially trying to do is to replicate
> ./ffmpeg -re -i TEST_VIDEO.ts -acodec copy -vcodec copy -f rtp_mpegts
> rtp://239.245.0.2:5002
>
> Streaming is happening, but the quality is terrible.
> Looks like many frames are skipped plus streaming is happening really
> slow(buffer underflow reported by VLC player)
>
> File plays perfectly fine directly on VLC player.
> Please help.
>
> Stream details.
> Input #0, mpegts, from ' TEST_VIDEO.ts':
> Duration: 00:10:00.40, start: 41313.400811, bitrate: 2840 kb/s
> Program 1
> Stream #0:0[0x11]: Video: h264 (High) ([27][0][0][0] / 0x001B),
> yuv420p(tv, bt709, top first), 1440x1080 [SAR 4:3 DAR 16:9], 29.97
> fps, 59.94 tbr, 90k tbn, 59.94 tbc
> Stream #0:1[0x14]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz,
> stereo, fltp, 448 kb/s
> Output #0, rtp_mpegts, to 'rtp://239.255.0.2:5004':
> Metadata:
> encoder : Lavf57.83.100
> Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B),
> yuv420p(tv, bt709, top first), 1440x1080 [SAR 4:3 DAR 16:9], q=2-31,
> 29.97 fps, 59.94 tbr, 90k tbn, 29.97 tbc
> Stream #0:1: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo,
> fltp, 448 kb/s
> Stream mapping:
> Stream #0:0 -> #0:0 (copy)
> Stream #0:1 -> #0:1 (copy)
> Press [q] to stop, [?] for help
> frame= 418 fps=5.2 q=-1.0 size= 3346kB time=00:00:08.50
> bitrate=3223.5kbits/s speed=0.106x
> Thanks
> Benji
>
>
> My complete source code(This is almost same as remuxing.c)
>
>
> #include <libavutil/timestamp.h>
> #include <libavformat/avformat.h>
>
> static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket
> *pkt, const char *tag)
> {
> AVRational *time_base = &fmt_ctx->streams[pkt->stream_
> index]->time_base;
>
> printf("%s: pts:%s pts_time:%s dts:%s dts_time:%s duration:%s
> duration_time:%s stream_index:%d\n",
> tag,
> av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
> av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
> av_ts2str(pkt->duration), av_ts2timestr(pkt->duration,
> time_base),
> pkt->stream_index);
> }
>
>
> int main(int argc, char **argv)
> {
> AVOutputFormat *ofmt = NULL;
> AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
> AVPacket pkt;
> const char *in_filename, *out_filename;
> int ret, i;
> int stream_index = 0;
> int *stream_mapping = NULL;
> int stream_mapping_size = 0;
> AVRational mux_timebase;
> int64_t start_time = 0; //(of->start_time == AV_NOPTS_VALUE) ? 0 :
> of->start_time;
> int64_t ost_tb_start_time = 0; //av_rescale_q(start_time,
> AV_TIME_BASE_Q, ost->mux_timebase);
>
> if (argc < 3) {
> printf("usage: %s input output\n"
> "API example program to remux a media file with
> libavformat and libavcodec.\n"
> "The output format is guessed according to the file
> extension.\n"
> "\n", argv[0]);
> return 1;
> }
>
> in_filename = argv[1];
> out_filename = argv[2];
>
> av_register_all();
> avcodec_register_all();
> avformat_network_init();
>
> if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
> fprintf(stderr, "Could not open input file '%s'", in_filename);
> goto end;
> }
>
> if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
> fprintf(stderr, "Failed to retrieve input stream information");
> goto end;
> }
>
> av_dump_format(ifmt_ctx, 0, in_filename, 0);
>
> avformat_alloc_output_context2(&ofmt_ctx, NULL, "rtp_mpegts",
> out_filename);
> if (!ofmt_ctx) {
> fprintf(stderr, "Could not create output context\n");
> ret = AVERROR_UNKNOWN;
> goto end;
> }
>
> stream_mapping_size = ifmt_ctx->nb_streams;
> stream_mapping = av_mallocz_array(stream_mapping_size,
> sizeof(*stream_mapping));
> if (!stream_mapping) {
> ret = AVERROR(ENOMEM);
> goto end;
> }
>
> ofmt = ofmt_ctx->oformat;
>
> for (i = 0; i < ifmt_ctx->nb_streams; i++)
> {
> AVStream *out_stream;
> AVStream *in_stream = ifmt_ctx->streams[i];
> AVCodecParameters *in_codecpar = in_stream->codecpar;
>
> if (in_codecpar->codec_type != AVMEDIA_TYPE_AUDIO &&
> in_codecpar->codec_type != AVMEDIA_TYPE_VIDEO &&
> in_codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
> stream_mapping[i] = -1;
> continue;
> }
>
> stream_mapping[i] = stream_index++;
>
>
> out_stream = avformat_new_stream(ofmt_ctx, NULL);
> if (!out_stream) {
> fprintf(stderr, "Failed allocating output stream\n");
> ret = AVERROR_UNKNOWN;
> goto end;
> }
>
> //out_stream->codecpar->codec_tag = 0;
> if (0 == out_stream->codecpar->codec_tag)
> {
> unsigned int codec_tag_tmp;
>
> if (!out_stream->codecpar->codec_tag ||
> av_codec_get_id (ofmt->codec_tag,
> in_codecpar->codec_tag) == in_codecpar->codec_id ||
> !av_codec_get_tag2(ofmt->codec_tag,
> in_codecpar->codec_id, &codec_tag_tmp))
> out_stream->codecpar->codec_tag = in_codecpar->codec_tag;
> }
> //ret = avcodec_parameters_to_context(ost->enc_ctx,
> ist->st->codecpar);
>
> ret = avcodec_parameters_copy(out_stream->codecpar, in_codecpar);
> if (ret < 0) {
> fprintf(stderr, "Failed to copy codec parameters\n");
> goto end;
> }
> //out_stream->codecpar->codec_tag = codec_tag;
> // copy timebase while removing common factors
>
> printf("bit_rate %lld sample_rate %d frame_size %d\n",
> in_codecpar->bit_rate, in_codecpar->sample_rate,
> in_codecpar->frame_size);
>
> out_stream->avg_frame_rate = in_stream->avg_frame_rate;
>
> ret = avformat_transfer_internal_stream_timing_info(ofmt,
>
> out_stream, in_stream,
>
> AVFMT_TBCF_AUTO);
> if (ret < 0) {
> fprintf(stderr,
> "avformat_transfer_internal_stream_timing_info failed\n");
> goto end;
> }
>
> if (out_stream->time_base.num <= 0 || out_stream->time_base.den <=
> 0)
> out_stream->time_base =
> av_add_q(av_stream_get_codec_timebase(out_stream), (AVRational){0,
> 1});
>
> // copy estimated duration as a hint to the muxer
> if (out_stream->duration <= 0 && in_stream->duration > 0)
> out_stream->duration = av_rescale_q(in_stream->duration,
> in_stream->time_base, out_stream->time_base);
>
> // copy disposition
> out_stream->disposition = in_stream->disposition;
>
> out_stream->sample_aspect_ratio = in_stream->sample_aspect_ratio;
> out_stream->avg_frame_rate = in_stream->avg_frame_rate;
> out_stream->r_frame_rate = in_stream->r_frame_rate;
>
> if ( in_codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
> {
>
> mux_timebase = in_stream->time_base;
> }
>
>
> if (in_stream->nb_side_data) {
> for (i = 0; i < in_stream->nb_side_data; i++) {
> const AVPacketSideData *sd_src = &in_stream->side_data[i];
> uint8_t *dst_data;
>
> dst_data = av_stream_new_side_data(out_stream,
> sd_src->type, sd_src->size);
> if (!dst_data)
> return AVERROR(ENOMEM);
> memcpy(dst_data, sd_src->data, sd_src->size);
> }
> }
> }
>
> av_dump_format(ofmt_ctx, 0, out_filename, 1);
>
> start_time = ofmt_ctx->duration;
> ost_tb_start_time = av_rescale_q(ofmt_ctx->duration,
> AV_TIME_BASE_Q, mux_timebase);
>
> if (!(ofmt->flags & AVFMT_NOFILE))
> {
> ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
> if (ret < 0) {
> fprintf(stderr, "Could not open output file '%s'",
> out_filename);
> goto end;
> }
> }
>
> ret = avformat_write_header(ofmt_ctx, NULL);
> if (ret < 0) {
> fprintf(stderr, "Error occurred when opening output file\n");
> goto end;
> }
>
> while (1)
> {
> AVStream *in_stream, *out_stream;
>
> ret = av_read_frame(ifmt_ctx, &pkt);
> if (ret < 0)
> break;
>
> in_stream = ifmt_ctx->streams[pkt.stream_index];
> if (pkt.stream_index >= stream_mapping_size ||
> stream_mapping[pkt.stream_index] < 0) {
> av_packet_unref(&pkt);
> continue;
> }
>
> pkt.stream_index = stream_mapping[pkt.stream_index];
> out_stream = ofmt_ctx->streams[pkt.stream_index];
>
> //log_packet(ifmt_ctx, &pkt, "in");
>
>
> //ofmt_ctx->bit_rate = ifmt_ctx->bit_rate;
> ofmt_ctx->duration = ifmt_ctx->duration;
> /* copy packet */
> //pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base,
> out_stream->time_base, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);
> //pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base,
> out_stream->time_base, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);
>
> if (pkt.pts != AV_NOPTS_VALUE)
> pkt.pts = av_rescale_q(pkt.pts,
> in_stream->time_base,mux_timebase) - ost_tb_start_time;
> else
> pkt.pts = AV_NOPTS_VALUE;
>
> if (pkt.dts == AV_NOPTS_VALUE)
> pkt.dts = av_rescale_q(pkt.dts, AV_TIME_BASE_Q, mux_timebase);
> else
> pkt.dts = av_rescale_q(pkt.dts, in_stream->time_base,
> mux_timebase);
> pkt.dts -= ost_tb_start_time;
>
> pkt.duration = av_rescale_q(pkt.duration,
> in_stream->time_base, mux_timebase);
> //pkt.duration = av_rescale_q(1,
> av_inv_q(out_stream->avg_frame_rate), mux_timebase);
> pkt.pos = -1;
> //log_packet(ofmt_ctx, &pkt, "out");
>
>
> ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
> if (ret < 0) {
> fprintf(stderr, "Error muxing packet\n");
> break;
> }
> av_packet_unref(&pkt);
> }
>
> av_write_trailer(ofmt_ctx);
> end:
>
> avformat_close_input(&ifmt_ctx);
>
> /* close output */
> if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
> avio_closep(&ofmt_ctx->pb);
> avformat_free_context(ofmt_ctx);
>
> av_freep(&stream_mapping);
>
> if (ret < 0 && ret != AVERROR_EOF) {
> fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
> return 1;
> }
>
> return 0;
> }
> _______________________________________________
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> Libav-user at ffmpeg.org
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>
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