MKV muxer corrupts subtitles
|Reported by:||ValdikSS||Owned by:||ValdikSS|
|Blocking:||Reproduced by developer:||no|
|Analyzed by developer:||no|
Summary of the bug:
Remuxing MKV with embedded subtitles can cause some sort of subtitles corruption in the resulting MKV file. Some lines or karaoke effects could disappear in certain video players.
How to reproduce:
I've uploaded 2 files into incoming folder on FTP: mkv_subtitles.mkv (http://yadi.sk/d/NM69ZxZQKzNn7) and mkv_subtitles_ffmpeg.mkv (http://yadi.sk/d/qDFmsDPQKzNoQ). The second one was remuxed with the following command:
ffmpeg -i mkv_subtitles.mkv -map 0 -map_metadata 0 -c copy mkv_subtitles_ffmpeg.mkv
Subtitles in the first file are played correctly while in ffmpeg-remuxed file some karaoke effects and english translation is missing (tested with cmplayer, vlc, mpv and mplayer. It works correctly only in mplayer).
If you extract subtitles with
mkvextract tracks mkv_subtitles.mkv 1:sub_orig.ass mkvextract tracks mkv_subtitles_ffmpeg.mkv 1:sub_ffmpeg.ass
you can see the difference between them (with diff).
But if you remux MKV with extracted subtitles (extracted either with ffmpeg or mkvextract, either from original or remuxed mkv with broken subtitles), it works fine.
ffmpeg -i mkv_subtitles.mkv -i sub_ffmpeg.ass -map 0 -map -0:s -map 1 -c copy test.mkv