[Libav-user] Remuxing/Codec copy over rtp_mpegts really bad quality result

Benji Amello benji.amello at gmail.com
Wed Jan 3 08:19:07 EET 2018


As all the experts are back from vacation,  can some one have a quick look
on my issue.

Thanks
Benji

On Jan 1, 2018 5:37 PM, "Benji Amello" <benji.amello at gmail.com> wrote:

> Happy New Year!
> Can any libav experts have a look on the quality of streaming issue I am
> facing?
>
> Thanks
> Benji
>
> On Wed, Dec 27, 2017 at 1:12 PM, Benji Amello <benji.amello at gmail.com>
> wrote:
> > 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;
> >> }
> >> _______________________________________________
> >> Libav-user mailing list
> >> Libav-user at ffmpeg.org
> >> http://ffmpeg.org/mailman/listinfo/libav-user
> >
> >
> >
> > _______________________________________________
> > Libav-user mailing list
> > Libav-user at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/libav-user
> >
>
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