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avformat/movenc: Fix flush fragment

The follow cmd output corrupted file before the patch: ffmpeg -f lavfi -i color=blue,trim=duration=0.04 \ -f lavfi -i anullsrc,atrim=duration=2 \ -movflags +empty_moov+hybrid_fragmented \ -frag_duration 1000000 \ -frag_interleave 1 \ output.mp4 1. first_track is the first track with track->entry != 0. As in the command above, video track (track index 0) has a single frame. When flush the second fragment, first_track is 1, the audio track. 2. write_moof = i == first_track, so write_moof is false for i = 0. 3. When mov->frag_interleave != 0, mov->mdat_buf != NULL, because it contains audio data. So avio_write is called before write_moof, that is, the data write before moof, and mov_finish_fragment executed with wrong mdat_start. 4. With normal fmp4 output, the error isn't obvious. With hybrid_fragmented, ffplay output.mp4 shows a lot of error messages.

Zhao Zhili committed 1 year ago

Commit 56cf1c01 parent 3d9b2842 files · +7 −2Browse files

Unified · Split

2 files
  1. libavformat/movenc.c +2 −2
  2. tests/fate/mov.mak +5 −0
libavformat/movenc.c+2−2
@@ -6509,9 +6509,9 @@ static int mov_flush_fragment(AVFormatContext *s, int force) · 6508 unmodified lines
6509 int buf_size, write_moof = 1, moof_tracks = -1;6509 int buf_size, write_moof = 1, moof_tracks = -1;
6510 uint8_t *buf;6510 uint8_t *buf;
6511 6511
6512 if (!track->entry)
6513 continue;
6512 if (mov->flags & FF_MOV_FLAG_SEPARATE_MOOF) {6514 if (mov->flags & FF_MOV_FLAG_SEPARATE_MOOF) {
6513 if (!track->entry)
6514 continue;
6515 mdat_size = avio_tell(track->mdat_buf);6515 mdat_size = avio_tell(track->mdat_buf);
6516 moof_tracks = i;6516 moof_tracks = i;
6517 } else {6517 } else {
tests/fate/mov.mak+5−0
@@ -84,6 +84,11 @@ fate-mov-ibi-elst-starts-b: CMD = framemd5 -flags +bitexact -i $(TARGET_SAMPLES) · 83 unmodified lines
84# Makes sure that we handle overlapping framgments84# Makes sure that we handle overlapping framgments
85fate-mov-frag-overlap: CMD = framemd5 -i $(TARGET_SAMPLES)/mov/frag_overlap.mp485fate-mov-frag-overlap: CMD = framemd5 -i $(TARGET_SAMPLES)/mov/frag_overlap.mp4
86 86
87fate-mov-mp4-frag-flush: CMD = md5 -f lavfi -i color=blue,format=rgb24,trim=duration=0.04 -f lavfi -i anullsrc,aformat=s16,atrim=duration=2 -c:v png -c:a pcm_s16le -movflags +empty_moov+hybrid_fragmented -frag_duration 1000000 -frag_interleave 1 -f mp4
88fate-mov-mp4-frag-flush: CMP = oneline
89fate-mov-mp4-frag-flush: REF = a10c0e2e2dfc120f31ca5e59e0e4392a
90FATE_MOV-$(call ALLYES, LAVFI_INDEV, COLOR_FILTER, FORMAT_FILTER, TRIM_FILTER, ANULL_FILTER, AFORMAT_FILTER, ATRIM_FILTER, PNG_ENCODER, PCM_S16LE_ENCODER, MOV_MUXER) += fate-mov-mp4-frag-flush
91
87# Makes sure that we pick the right frames according to edit list when there is no keyframe with PTS < edit list start.92# Makes sure that we pick the right frames according to edit list when there is no keyframe with PTS < edit list start.
88# For example, when video starts on a B-frame, and edit list starts on that B-frame too.93# For example, when video starts on a B-frame, and edit list starts on that B-frame too.
89# GOP structure : B B I in presentation order.94# GOP structure : B B I in presentation order.

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