[FFmpeg-trac] #9867(undetermined:new): Cannot remove "default" disposition of mov_text subtitle in mp4

[FFmpeg]

#9867: Cannot remove "default" disposition of mov_text subtitle in mp4
-------------------------------------+-------------------------------------
             Reporter:  liancea      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 When trying to remove the default disposition of a mov_text subtitle
 inside mp4 with either `-disposition:s:0 0` or `-disposition:s:0
 -default`, the output file still has the default disposition enabled.
 Setting `-default_mode` to `infer_no_subs` or `passthrough` doesn't change
 the outcome. (This may only have worked for mkv in the first place, but I
 wasn't sure.)

 I included instructions for a minimal file for reproducing the issue, but
 I could also upload a real world example with audio and video in it, if
 desired. The behavior was identical for me.

 How to reproduce:
 {{{
 # Create sample file (linux/mac shell)
 % echo -e '1\n00:00:00,000 --> 00:01:00,000\nTest' > subtest.srt
 % ffmpeg -i subtest.srt -map 0 -c mov_text subtest.mp4


 # Check if sample file has a default subtitle
 % ffmpeg -hide_banner -i subtest.mp4
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'subtest.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2mp41
     encoder         : Lavf59.30.100
   Duration: 00:01:00.00, start: 0.000000, bitrate: 0 kb/s
   Stream #0:0[0x1](und): Subtitle: mov_text (tx3g / 0x67337874), 0 kb/s
 (default)
     Metadata:
       handler_name    : SubtitleHandler
 At least one output file must be specified


 # Try to remove default disposition
 % ffmpeg -i subtest.mp4 -map 0 -c copy -disposition:s:0 0 subtest-
 after.mp4
 # or ...
 % ffmpeg -i subtest.mp4 -map 0 -c copy -disposition:s:0 -default subtest-
 after.mp4
 ffmpeg version N-107731-g5cdf4c0bed Copyright (c) 2000-2022 the FFmpeg
 developers
   built with gcc 11 (Ubuntu 11.2.0-19ubuntu1)
   configuration: --prefix=/home/pauling/ffmpeg_build --pkg-config-
 flags=--static --extra-cflags=-I/home/pauling/ffmpeg_build/include
 --extra-ldflags=-L/home/pauling/ffmpeg_build/lib --extra-libs='-lpthread
 -lm' --ld=g++ --bindir=/home/pauling/bin --enable-gpl --enable-gnutls
 --enable-libaom --enable-libass --enable-libfdk-aac --enable-libfreetype
 --enable-libmp3lame --enable-libopus --enable-libsvtav1 --enable-libdav1d
 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265
 --enable-nonfree
   libavutil      57. 32.101 / 57. 32.101
   libavcodec     59. 42.100 / 59. 42.100
   libavformat    59. 30.100 / 59. 30.100
   libavdevice    59.  8.101 / 59.  8.101
   libavfilter     8. 46.101 /  8. 46.101
   libswscale      6.  8.102 /  6.  8.102
   libswresample   4.  8.100 /  4.  8.100
   libpostproc    56.  7.100 / 56.  7.100
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'subtest.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2mp41
     encoder         : Lavf59.30.100
   Duration: 00:01:00.00, start: 0.000000, bitrate: 0 kb/s
   Stream #0:0[0x1](und): Subtitle: mov_text (tx3g / 0x67337874), 0 kb/s
 (default)
     Metadata:
       handler_name    : SubtitleHandler
 Output #0, mp4, to 'subtest-after.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2mp41
     encoder         : Lavf59.30.100
   Stream #0:0(und): Subtitle: mov_text (tx3g / 0x67337874), 0 kb/s
     Metadata:
       handler_name    : SubtitleHandler
 Stream mapping:
   Stream #0:0 -> #0:0 (copy)
 Press [q] to stop, [?] for help
 size=       1kB time=00:00:00.00 bitrate=N/A speed=   0x
 video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 12933.333008%


 # Confirm whether default disposition is gone
 % ffmpeg -hide_banner -i subtest-after.mp4
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'subtest-after.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2mp41
     encoder         : Lavf59.30.100
   Duration: 00:01:00.00, start: 0.000000, bitrate: 0 kb/s
   Stream #0:0[0x1](und): Subtitle: mov_text (tx3g / 0x67337874), 0 kb/s
 (default)
     Metadata:
       handler_name    : SubtitleHandler
 At least one output file must be specified
 }}}
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9867>
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