>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 <nicolas.gaullier@cji.paris> 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="2.060000" >> streams.stream.1.duration="1.176000" >>After patch: >> streams.stream.0.duration="2.080000" >> streams.stream.1.duration="1.200000" >> >> >>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.
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