Opened 2 years ago
Last modified 2 years ago
#10135 new defect
matroska/ass: Wrong AVPacket duration set for ass events with 0 duration
| Reported by: | enen92 | Owned by: | |
|---|---|---|---|
| Priority: | normal | Component: | avformat |
| Version: | git-master | Keywords: | mkv, ass |
| Cc: | enen92 | Blocked By: | |
| Blocking: | Reproduced by developer: | no | |
| Analyzed by developer: | no |
Description
Summary of the bug:
Reported to Kodi (https://github.com/xbmc/xbmc/issues/21625) but the root cause seems to be in libav. The subtitle AVPackets returned from the demuxer have a duration > 0 that seems to result from the pts value that the next subtitle is received.
Those subtitle events have start and end times equal to 0 and should not be shown:
Dialogue: 0,0:00:00.00,0:00:00.00,DCMain,CONAN,0000,0000,0000,,[ed] Dialogue: 0,0:00:00.00,0:00:00.00,DCMain,KOGORO,0000,0000,0000,,[eyecatch] Dialogue: 0,0:00:00.00,0:00:00.00,DCMain,,0000,0000,0000,,Detective Conan Episode 1047 "The \NRed Sheep's Eerie Game (Part One)" Dialogue: 0,0:00:00.00,0:00:00.00,DCMain,CONAN,0000,0000,0000,,[op]
Initially matroskadec sets the start and duration times correctly (both 0) but at some point along the chain the duration is changed.
How to reproduce:
% ffplay -vf subtitles=filename="ass_sample.mkv" ass_sample.mkv ffmpeg version master built on linux (although it happens on all platforms)
The entries "[ed]", "[eyecatch]", "Detective Conan Episode 1047 "The \NRed Sheep's Eerie Game (Part One)", "[op]" should not be shown. Opening the same file with mpv shows the correct behaviour (they don't rely on the duration from AVPacket)
Sample file is here:
https://www.mediafire.com/file/d6itonjk5z21j0r/1047_%255BErai-raws%255D_%25281%2529-001.mkv/file