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

Benji Amello benji.amello at gmail.com
Tue Jan 2 02:37:46 EET 2018


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
>


More information about the Libav-user mailing list