When doing an mp3 → mp3 (or flac → mp3) conversion, -map_metadata can be used to copy metadata from the input file to the output file:
ffmpeg -hide_banner -loglevel warning -nostats -i "${source}" -map_metadata 0 -vn -ar 44100 -b:a 256k -f mp3 "${target}"
However, when I use this, I notice that it doesn't copy all the metadata correctly. Using the tool eyeD3, I inspecting the input and output files see this:
$ eyeD3 input.mp3
input.mp3 [ 4.15 MB ]
--------------------------------------------------------------------------------
Time: 01:46 MPEG1, Layer III [ 320 kb/s @ 44100 Hz - Stereo ]
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ID3 v2.3:
title: Track title
artist: Artist Name
album: Album Name
album artist: Various Artists
composer: Composer Name
recording date: 2019
eyed3.id3:WARNING: Non standard genre name: Soundtracks
track: 17/37 genre: Soundtracks (id None)
disc: 1/1
FRONT_COVER Image: [Size: 86555 bytes] [Type: image/jpeg]
Description:
PRIV: [Data: 42 bytes]
Owner Id: Google/StoreId
PRIV: [Data: 40 bytes]
Owner Id: Google/StoreLabelCode
--------------------------------------------------------------------------------
$ eyeD3 path/to/output.mp3
/tmp/test.mp3 [ 3.26 MB ]
--------------------------------------------------------------------------------
Time: 01:46 MPEG1, Layer III [ 256 kb/s @ 44100 Hz - Stereo ]
--------------------------------------------------------------------------------
ID3 v2.4:
title: Track title
artist: Artist Name
album: Album Name
album artist: Various Artists
composer: Composer Name
recording date: 2019
eyed3.id3:WARNING: Non standard genre name: Soundtracks
track: 17/37 genre: Soundtracks (id None)
disc: 1/1
PRIV: [Data: 40 bytes]
Owner Id: Google/StoreLabelCode
PRIV: [Data: 42 bytes]
Owner Id: Google/StoreId
--------------------------------------------------------------------------------
Specifically, it's not copying the FRONT_COVER image correctly - somehow it's being dropped along the way.
How can I ensure that the FRONT_COVER Image is copied during the conversion process?
