[FFmpeg-trac] #5825(undetermined:new): Vobsub subtitles won't overlay with some MKV

[FFmpeg]

#5825: Vobsub subtitles won't overlay with some MKV
-------------------------------------+-------------------------------------
             Reporter:  edumj        |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:  MKV, vobsub  |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Vobsub subtitles won't overlay with some MKV

 Summary of the bug: Some MKVs with vobsub subtitles won't show when I try
 to overlay them. It Works with this file
 http://samples.mplayerhq.hu/sub/largeres_vobsub.mkv, but doesn't with this
 one https://mega.nz/#!2JVTjZga

 The only difference I see in MediaInfo is that the one that doesn't show,
 doesn't have a Muxing Mode (zlib in the one that works).

 I've tried with scaling both video and subs to the same size, then
 overlay:
 {{{
  "%~dps0\ffmpeg"        -analyzeduration 15000000       -ss 10  -i %1
 -filter_complex
 "[0:v]scale=720:576[video],[0:s:0]scale=720:576[subs],[video][subs]overlay[out]"
 -map "[out]" -map 0:a:0             -f avi -vcodec mpeg4 -b:v 3000k -vtag
 XVID -c:a libmp3lame -b:a 128k                     - | "C:\Program Files
 (x86)\VideoLAN\VLC\vlc.exe" -
 }}}
 I've tried changing color palette of subs (also all with "ffffff"):
 {{{
  "%~dps0\ffmpeg"        -analyzeduration 15000000       -ss 10  -palette
 "ffffff,ffffff,ffffff,ffffff,000000,000000,000000,000000,000000,000000,000000,000000,ffffff,ffffff,ffffff,ffffff"
 -i %1      -filter_complex
 "[0:v]scale=720:576[video],[0:s:0]scale=720:576[subs],[video][subs]overlay[out]"
 -map "[out]" -map 0:a:0             -f avi -vcodec mpeg4 -b:v 3000k -vtag
 XVID -c:a libmp3lame -b:a 128k                     - | "C:\Program Files
 (x86)\VideoLAN\VLC\vlc.exe" -
 }}}
 And also a black (or gey) .png for the background:
 {{{
  "%~dps0\ffmpeg"        -analyzeduration 15000000       -loop 1         -i
 "%~dps0\720x576_gris.png"            -ss 30  -i %1      -filter_complex
 "[0:v]scale=720:576[video],[1:s:0]scale=720:576[subs],[video][subs]overlay[out]"
 -map "[out]"                -f avi -vcodec mpeg4 -b:v 3000k -vtag XVID
 - | "C:\Program Files (x86)\VideoLAN\VLC\vlc.exe" -
 }}}
 But none work.


 How to reproduce:
 {{{
 ffmpeg versión 20160825-01aee81
 built on 24-8-2016
 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/5825>
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