unsupported/unrecognized subtitle file format

[dolohow]

Summary of the bug:
When trying to play a video with subtitles using ffplay the program fails to load a subtitle file.

How to reproduce:

% ffplay file.mkv -sst file.txt

ffplay version 3.0.1 Copyright (c) 2003-2016 the FFmpeg developers
  built with gcc 5.3.0 (GCC)
  configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-avisynth --enable-avresample --enable-fontconfig --enable-gnutls --enable-gpl --enable-ladspa --enable-libass --enable-libbluray --enable-libdcadec --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-shared --enable-version3 --enable-x11grab
  libavutil      55. 17.103 / 55. 17.103
  libavcodec     57. 24.102 / 57. 24.102
  libavformat    57. 25.100 / 57. 25.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 31.100 /  6. 31.100
  libavresample   3.  0.  0 /  3.  0.  0
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, matroska,webm, from 'file.mkv':
    Stream #0:0(eng): Video: h264 (High), yuv420p, 1280x720, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
    Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 384 kb/s (default)
    Metadata:
      title           : English
Stream specifier file.txt does not match any subtitle stream

[dolohow]

subtitle file mentioned in this bug report

[Carl Eugen Hoyos]

Please post all usage question on the user mailing list: -sst does not accept a file name as argument.

[gjdfgh]

This user was actually reporting a bug that affects mpv. mpv can open external subtitle files. It failed with the given sample file, because libavformat does not properly recognize it. The user just tried to reproduce it with ffmpeg-native utilities.

If you run ffprobe on the file, you'll find that it prints

    Stream #0:0: Video: ansi, pal8, 640x400, 25 fps, 25 tbr, 25 tbn, 25 tbc

which is wrong.

[Cigaes]

Then please change the wording of the ticket.

But what kind of subtitle is this file supposed to be? And what program does support it?

[gjdfgh]

Then please change the wording of the ticket.

Of course.

But what kind of subtitle is this file supposed to be?

No clue really. Looks like it might match with the "vplayer" format.

And what program does support it?

VLC.

[Cigaes]

Replying to gjdfgh:

Of course.

Thanks.

No clue really. Looks like it might match with the "vplayer" format.

According to $FATE/sub/VPlayer_capability_tester.txt, it does not look likely.

VLC.

Fair point. Does it print any information on the format? If not, a look at the source to see what code handles it would probably be useful.

[gjdfgh]

Mixed them up. I mean MPL2.

I think it fails because mpl2dec.c doesn't skip the BOM.

[Carl Eugen Hoyos]

Replying to gjdfgh:

Mixed them up. I mean MPL2.

I think it fails because mpl2dec.c doesn't skip the BOM.

Isn't this a duplicate of ticket #3718 for which you promised a patch?

[gjdfgh]

for which you promised a patch?

Where did I promise this?

[Elon Musk]

Fixed in 74267333a10e0be4355221d7be22dab73bd7184c.