PR #20623 opened by Zhao Zhili (quink) URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20623 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20623.patch
sidx earliest_presentation_time as the name says, is in presentation timeline. I made a mistake in 301141b, which intended to create presentation time, but finally created media time. There is a bug in mp4 demuxer, which did the reverse: it minus sidx_pts by sc->time_offset to get presentation time, while sidx_pts is already in presentation timeline. This patchset fix mp4 demuxer and revert the bug in mp4 muxer. Muxer test: ``` ./ffmpeg -f lavfi -i testsrc2 -f lavfi -i sine=sample_rate=48000 -af [1:a]asetpts=expr=PTS+2*SR -c:v libx264 -bf 0 -c:a aac -movflags cmaf+global_sidx+delay_moov -global_sidx 1 -t 10 out.mp4 ``` Check editlist and sidx. Demuxer test: ``` ./ffprobe -show_packets -use_tfdt 0 out.mp4 ./ffprobe -show_packets -use_tfdt 1 out.mp4 ``` Check the first audio packet timestamp. >From 9f115aa8b1c043a0af15887babef7b31ac183117 Mon Sep 17 00:00:00 2001 From: Zhao Zhili <[email protected]> Date: Sun, 28 Sep 2025 17:23:05 +0800 Subject: [PATCH 1/2] avformat/mov: don't shift sidx_pts sidx_pts is already in presentation time, so it shouldn't be shift by sc->time_offset again. --- libavformat/mov.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavformat/mov.c b/libavformat/mov.c index 7fe4678234..9ce066a9a2 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -5839,7 +5839,7 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom) } else if (has_sidx && !c->use_tfdt || fallback_sidx) { // FIXME: sidx earliest_presentation_time is *PTS*, s.b. // pts = frag_stream_info->sidx_pts; - dts = frag_stream_info->sidx_pts - sc->time_offset; + dts = frag_stream_info->sidx_pts; av_log(c->fc, AV_LOG_DEBUG, "found sidx time %"PRId64 ", using it for dts\n", frag_stream_info->sidx_pts); } else { -- 2.49.1 >From 7d3ae113fec5597e8a7b7365d2cc402fc7f39d36 Mon Sep 17 00:00:00 2001 From: Zhao Zhili <[email protected]> Date: Sun, 28 Sep 2025 17:35:41 +0800 Subject: [PATCH 2/2] Revert "avformat/movenc: sidx earliest_presentation_time is applied after editlist" This reverts commit 301141b57636c4430e7440e8ff4956daf9cb0fb3. cluster[0].dts, pts and frag_info[0].time are already in presentation timeline, so they shouldn't be shift by start_pts. --- libavformat/movenc.c | 6 +----- tests/ref/fate/movenc | 10 +++++----- 2 files changed, 6 insertions(+), 10 deletions(-) diff --git a/libavformat/movenc.c b/libavformat/movenc.c index 067d38b14b..b76d56dac4 100644 --- a/libavformat/movenc.c +++ b/libavformat/movenc.c @@ -5690,8 +5690,7 @@ static int mov_write_sidx_tag(AVIOContext *pb, if (track->entry) { entries = 1; - presentation_time = track->cluster[0].dts + track->cluster[0].cts - - track->start_dts - track->start_cts; + presentation_time = track->cluster[0].dts + track->cluster[0].cts; duration = track->end_pts - (track->cluster[0].dts + track->cluster[0].cts); starts_with_SAP = track->cluster[0].flags & MOV_SYNC_SAMPLE; @@ -5706,9 +5705,6 @@ static int mov_write_sidx_tag(AVIOContext *pb, if (entries <= 0) return 0; presentation_time = track->frag_info[0].time; - /* presentation_time <= 0 is handled by mov_add_tfra_entries() */ - if (presentation_time > 0) - presentation_time -= track->start_dts + track->start_cts; } avio_wb32(pb, 0); /* size */ diff --git a/tests/ref/fate/movenc b/tests/ref/fate/movenc index 5c12aeb29f..f2b95ea957 100644 --- a/tests/ref/fate/movenc +++ b/tests/ref/fate/movenc @@ -101,28 +101,28 @@ write_data len 1223, time nopts, type header atom ftyp 041ac8efc35a0d023c26d05eedb20403 1223 delay-moov-elst-signal-init write_data len 1004, time -33333, type sync atom sidx write_data len 996, time 966667, type sync atom sidx -69c9025ffb10302c7b5c2ed9fde86c44 996 delay-moov-elst-signal-second-frag +5a583d89318827d2569eecbeaa18c238 996 delay-moov-elst-signal-second-frag write_data len 148, time nopts, type trailer atom - write_data len 1223, time nopts, type header atom ftyp 041ac8efc35a0d023c26d05eedb20403 1223 delay-moov-elst-signal-init-discont write_data len 996, time 966667, type sync atom sidx -69c9025ffb10302c7b5c2ed9fde86c44 996 delay-moov-elst-signal-second-frag-discont +5a583d89318827d2569eecbeaa18c238 996 delay-moov-elst-signal-second-frag-discont write_data len 110, time nopts, type trailer atom - write_data len 1247, time nopts, type header atom ftyp 80511a51d1ac9cde62337eed7176ae03 1247 delay-moov-elst-signal-init-discont-largets write_data len 996, time 279621233333, type sync atom sidx -471fc64644a6bf4065c489fe4e04be7d 996 delay-moov-elst-signal-second-frag-discont-largets +dc695d65e8a0cdafee28acd8a5ccf81a 996 delay-moov-elst-signal-second-frag-discont-largets write_data len 110, time nopts, type trailer atom - write_data len 1223, time nopts, type header atom ftyp write_data len 2572, time -333333, type sync atom sidx write_data len 996, time 5166667, type sync atom sidx write_data len 148, time nopts, type trailer atom - -5c873f6e37d5af09e3c6329cf94cd6ca 4939 vfr +d37a7eda807912b9ed05ccfe003a9e4f 4939 vfr write_data len 1223, time nopts, type header atom ftyp write_data len 2572, time -333333, type sync atom sidx write_data len 996, time 5166667, type sync atom sidx write_data len 148, time nopts, type trailer atom - -5c873f6e37d5af09e3c6329cf94cd6ca 4939 vfr-noduration +d37a7eda807912b9ed05ccfe003a9e4f 4939 vfr-noduration write_data len 1231, time nopts, type header atom ftyp write_data len 1500, time -333333, type sync atom moof write_data len 1500, time nopts, type unknown atom - -- 2.49.1 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
