ID3v2 compilation Tag on MP3 gets lost

[Sigi]

I am using ffmpeg just to edit ID3v2 tags of MP3 files on Win10.
During conversion the TCMP tag is lost.
The parameter -metadata compilation="1" doesn't work / fix this.
You can verify this bug by opening the TestNew.mp3 with any TAG-Editor.

E:\>ffmpeg.exe -i E:\Test.mp3 -c copy TestNew.mp3

Input #0, mp3, from 'E:\Test.mp3':

Metadata:

album_artist : Various Artists
album : Test-Album
artist : Test-Artist
comment :
title : Test-Title
compilation : 1
date : 2020

...
Output #0, mp3, to 'TestNew.mp3':

TPE2 : Various Artists
TALB : Test-Album
TPE1 : Test-Artist
comment :
TIT2 : Test-Title
TDRC : 2020
TCMP : 1

[Elon Musk]

To make this valid ticket report, provide mp3 file.

[Sigi]

Please see the attached files. Thank you :-)

E:\>ffmpeg -i input.mp3 -c copy OUTPUT.mp3
ffmpeg version 2023-06-15-git-41229ef705-essentials_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers

built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
libavutil 58. 13.100 / 58. 13.100
libavcodec 60. 18.100 / 60. 18.100
libavformat 60. 6.100 / 60. 6.100
libavdevice 60. 2.100 / 60. 2.100
libavfilter 9. 8.101 / 9. 8.101
libswscale 7. 3.100 / 7. 3.100
libswresample 4. 11.100 / 4. 11.100
libpostproc 57. 2.100 / 57. 2.100

[mp3 @ 00000290ed66edc0] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'input.mp3':

Metadata:

album_artist : Various Artists
comment :
title : Fade (NCS Release)
artist : Alan Walker
album : Test Album
compilation : 1
date : 2023

Duration: 00:00:48.77, start: 0.000000, bitrate: 256 kb/s
Stream #0:0: Audio: mp3, 44100 Hz, stereo, fltp, 256 kb/s

Output #0, mp3, to 'OUTPUT.mp3':

Metadata:

TPE2 : Various Artists
comment :
TIT2 : Fade (NCS Release)
TPE1 : Alan Walker
TALB : Test Album
TCMP : 1
TDRC : 2023
TSSE : Lavf60.6.100

Stream #0:0: Audio: mp3, 44100 Hz, stereo, fltp, 256 kb/s

Stream mapping:

Stream #0:0 -> #0:0 (copy)

Press [q] to stop, ? for help
[out#0/mp3 @ 00000290ed66f240] video:0kB audio:1524kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.066318%
size= 1525kB time=00:00:48.74 bitrate= 256.3kbits/s speed=3.28e+03x

E:\>

[elenril]

Your attached output file does contain the compilation tag, as seen by ffmpeg CLI:

ffmpeg -i OUTPUT.mp3 
ffmpeg version N-111316-gf7e1bcad49 Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12 (Debian 12.2.0-14)
  libavutil      58. 13.101 / 58. 13.101
  libavcodec     60. 22.100 / 60. 22.100
  libavformat    60. 10.100 / 60. 10.100
  libavdevice    60.  2.100 / 60.  2.100
  libavfilter     9.  8.102 /  9.  8.102
  libswscale      7.  3.100 /  7.  3.100
  libswresample   4. 11.100 /  4. 11.100
  libpostproc    57.  2.100 / 57.  2.100
Input #0, mp3, from 'OUTPUT.mp3':
  Metadata:
    album_artist    : Various Artists
    comment         : 
    title           : Fade (NCS Release)
    artist          : Alan Walker
    album           : Test Album
    compilation     : 1
    date            : 2023
    encoder         : Lavf60.6.100
  Duration: 00:00:48.77, start: 0.011995, bitrate: 256 kb/s
  Stream #0:0: Audio: mp3, 44100 Hz, stereo, fltp, 256 kb/s
    Metadata:
      encoder         : Lavf
At least one output file must be specified

[Sigi]

BUG proof

[Sigi]

Aha, and you only saw it there? This is why I call it "bug" ;-)

I have added a screnshot for you.