Re: [FFmpeg-devel] [PATCH v3 0/1] avformat/demux: fix accurate probing of durations in mpegts/ps
>Envoyé : lundi 22 avril 2024 14:32 >À : ffmpeg-devel@ffmpeg.org >Objet : Re: [FFmpeg-devel] [PATCH v3 0/1] avformat/demux: fix accurate probing >of durations in mpegts/ps > >>De : Nicolas Gaullier Envoyé : mardi 2 >>avril 2024 23:26 Objet : [PATCH v3 0/1] avformat/demux: fix accurate >>probing of durations in mpegts/ps >> >>v3: rebased after ed9363052f4b8b8 applied tonight (add >>duration_probesize AVOption) >> >>Note: I have no other plan for demux/probing; with these two patches, I can >>cover my use cases, especially mpegts-concats. >> >>For remembering, previous cover-letters: >> >>v1 >>ff_read_packet() is more lightweight, but it leads to important issues when >>looking for accurate durations. >>As a side effect, the code looks also simpler with regular av_read_frame() >>calls. >>1)Updates in the fate tests do exhibit most of the results. >> >>2)See also more directly the case of an audio PES containing many frames: >>>ffprobe tests/data/lavf/lavf.ts -select_streams a -show_entries >>>stream=duration -of flat >>Before patch: >> streams.stream.0.duration="0.757556" >>After patch: >> streams.stream.0.duration="1.018778" >> >>3)Here is an additional (commonplace) sample to demonstrate the benefit for >>twofields-encoded video: >>>https://0x0.st/HFbm.ts (say h264-50i_mp2.ts) >> >>>ffprobe h264-50i_mp2.ts -show_entries stream=duration -of flat >>Before patch: >> streams.stream.0.duration="2.06" >> streams.stream.1.duration="1.176000" >>After patch: >> streams.stream.0.duration="2.08" >> streams.stream.1.duration="1.20" >> >> >>v2 >>v1: There was an issue with teletext where resolution is set just once at >>decoder init (teletext resolution is fixed/hard coded), so it is somewhat >>fragile: when a demuxer context update occurs, it is lost/overriden by >>>>avcodec_parameters_to_context(sti->avctx, st->codecpar) in >>read_frame_internal. >>They could have been other scenario besides teletext, I don't know. >>v2: So now at estimate_timings_from_pts, with one or more seeking involved >>(seeking is detected by the mpegts demuxer and set last_vn=-1, so pmt is >>forced/updated and results in demuxer context update), it is required to >>>>preserve the info in codecpar at first. >>Thanks to Michael for reporting the issue. >> >> >>Nicolas Gaullier (1): >> avformat/demux: Fix accurate probing of durations in mpegts/ps >> >> libavformat/demux.c | 36 ++-- >> tests/ref/fate/concat-demuxer-simple2-lavf-ts | 170 +- >> tests/ref/fate/ts-opus-demux | 4 +- >> 3 files changed, 100 insertions(+), 110 deletions(-) > >Ping for review ? >The patch (https://patchwork.ffmpeg.org/project/ffmpeg/list/?series=11386) >still applies on current master. >Thanks. Ping ? ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH v3 0/1] avformat/demux: fix accurate probing of durations in mpegts/ps
>De : Nicolas Gaullier >Envoyé : mardi 2 avril 2024 23:26 >Objet : [PATCH v3 0/1] avformat/demux: fix accurate probing of durations in >mpegts/ps > >v3: rebased after ed9363052f4b8b8 applied tonight (add duration_probesize >AVOption) > >Note: I have no other plan for demux/probing; with these two patches, I can >cover my use cases, especially mpegts-concats. > >For remembering, previous cover-letters: > >v1 >ff_read_packet() is more lightweight, but it leads to important issues when >looking for accurate durations. >As a side effect, the code looks also simpler with regular av_read_frame() >calls. >1)Updates in the fate tests do exhibit most of the results. > >2)See also more directly the case of an audio PES containing many frames: >>ffprobe tests/data/lavf/lavf.ts -select_streams a -show_entries >>stream=duration -of flat >Before patch: > streams.stream.0.duration="0.757556" >After patch: > streams.stream.0.duration="1.018778" > >3)Here is an additional (commonplace) sample to demonstrate the benefit for >twofields-encoded video: >>https://0x0.st/HFbm.ts (say h264-50i_mp2.ts) > >>ffprobe h264-50i_mp2.ts -show_entries stream=duration -of flat >Before patch: > streams.stream.0.duration="2.06" > streams.stream.1.duration="1.176000" >After patch: > streams.stream.0.duration="2.08" > streams.stream.1.duration="1.20" > > >v2 >v1: There was an issue with teletext where resolution is set just once at >decoder init (teletext resolution is fixed/hard coded), so it is somewhat >fragile: when a demuxer context update occurs, it is lost/overriden by >>avcodec_parameters_to_context(sti->avctx, st->codecpar) in >read_frame_internal. >They could have been other scenario besides teletext, I don't know. >v2: So now at estimate_timings_from_pts, with one or more seeking involved >(seeking is detected by the mpegts demuxer and set last_vn=-1, so pmt is >forced/updated and results in demuxer context update), it is required to >>preserve the info in codecpar at first. >Thanks to Michael for reporting the issue. > > >Nicolas Gaullier (1): > avformat/demux: Fix accurate probing of durations in mpegts/ps > > libavformat/demux.c | 36 ++-- > tests/ref/fate/concat-demuxer-simple2-lavf-ts | 170 +- > tests/ref/fate/ts-opus-demux | 4 +- > 3 files changed, 100 insertions(+), 110 deletions(-) Ping for review ? The patch (https://patchwork.ffmpeg.org/project/ffmpeg/list/?series=11386) still applies on current master. Thanks. Nicolas ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
[FFmpeg-devel] [PATCH v3 0/1] avformat/demux: fix accurate probing of durations in mpegts/ps
v3: rebased after ed9363052f4b8b8 applied tonight (add duration_probesize AVOption) Note: I have no other plan for demux/probing; with these two patches, I can cover my use cases, especially mpegts-concats. For remembering, previous cover-letters: v1 ff_read_packet() is more lightweight, but it leads to important issues when looking for accurate durations. As a side effect, the code looks also simpler with regular av_read_frame() calls. 1)Updates in the fate tests do exhibit most of the results. 2)See also more directly the case of an audio PES containing many frames: >ffprobe tests/data/lavf/lavf.ts -select_streams a -show_entries >stream=duration -of flat Before patch: streams.stream.0.duration="0.757556" After patch: streams.stream.0.duration="1.018778" 3)Here is an additional (commonplace) sample to demonstrate the benefit for twofields-encoded video: https://0x0.st/HFbm.ts (say h264-50i_mp2.ts) >ffprobe h264-50i_mp2.ts -show_entries stream=duration -of flat Before patch: streams.stream.0.duration="2.06" streams.stream.1.duration="1.176000" After patch: streams.stream.0.duration="2.08" streams.stream.1.duration="1.20" v2 v1: There was an issue with teletext where resolution is set just once at decoder init (teletext resolution is fixed/hard coded), so it is somewhat fragile: when a demuxer context update occurs, it is lost/overriden by avcodec_parameters_to_context(sti->avctx, st->codecpar) in read_frame_internal. They could have been other scenario besides teletext, I don't know. v2: So now at estimate_timings_from_pts, with one or more seeking involved (seeking is detected by the mpegts demuxer and set last_vn=-1, so pmt is forced/updated and results in demuxer context update), it is required to preserve the info in codecpar at first. Thanks to Michael for reporting the issue. Nicolas Gaullier (1): avformat/demux: Fix accurate probing of durations in mpegts/ps libavformat/demux.c | 36 ++-- tests/ref/fate/concat-demuxer-simple2-lavf-ts | 170 +- tests/ref/fate/ts-opus-demux | 4 +- 3 files changed, 100 insertions(+), 110 deletions(-) -- 2.30.2 ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
