FFmpeg failing to create COMM ID3v2 tag

[Alex Gitelzon]

Summary of the bug:
FFmpeg, tested with version 4.2.2 and 4.3.1, seems to have a bug with mp3 ID3v2 tags. Primarily, when trying to create a comment tag, it gets created as TXXX:comment instead of COMM.

How to reproduce (with any existing mp3):

% /usr/bin/ffmpeg -i input.mp3 -codec copy -vn -sn -dn -id3v2_version 3 -write_id3v1 1 -metadata "Comment=Testing Comment" output.mp3
ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, mp3, from 'input.mp3':
  Metadata:
    encoder         : Lavf58.29.100
  Duration: 00:00:30.04, start: 0.025057, bitrate: 64 kb/s
    Stream #0:0: Audio: mp3, 44100 Hz, mono, fltp, 64 kb/s
Output #0, mp3, to 'output.mp3':
  Metadata:
    Comment         : Testing Comment
    TSSE            : Lavf58.29.100
    Stream #0:0: Audio: mp3, 44100 Hz, mono, fltp, 64 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
size=     235kB time=00:00:29.98 bitrate=  64.2kbits/s speed=6.47e+03x
video:0kB audio:235kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.173098%

I then use eyeD3 to read the file:

% eyeD3 output.mp3
/tmp/output.mp3                                                                                                                                                                                                                                                                                                [ 235.10 KB ]
----------------------------------------------------------------------------------------
Time: 00:30     MPEG1, Layer III        [ 64 kb/s @ 44100 Hz - Mono ]
----------------------------------------------------------------------------------------
ID3 v2.3:
title:
artist:
album:
track:
UserTextFrame: [Description: Comment]
Testing Comment

This is what the output show look like:

% eyeD3 output.mp3
/tmp/output.mp3                                                                                                                                                                                                                                                                                                [ 235.37 KB ]
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Time: 00:30     MPEG1, Layer III        [ 64 kb/s @ 44100 Hz - Mono ]
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ID3 v2.3:
title:
artist:
album:
track:
Comment: [Description: ] [Lang: eng]
Testing Comment

[xavierlaff]

I am impacted by this problem

Do you plan to work there soon?

[Georg]

Apologies for submitting duplicate #9191, and thank you to cehoyos for closing the duplicate and pointing me here.