ffprobe misses "title" tags on audio streams in mp4

[T]

title tags in audio streams in mp4 files (eg written by ffmpeg via -metadata:s:a:0 title=Something) are there (show up, for example, in VLC) but are not found/reported by ffprobe. Note that ffprobe finds/reports them correctly in matroksa files.

Trivially reproduced. In an empty directory, this will show it:

ffmpeg -f lavfi -i nullsrc=s=640x480 -filter_complex 'geq=random(1)*255:128:128;aevalsrc=-2+random(0)[av],anoisesrc=d=5:c=pink:r=44100:a=0.5[aud]' -map '[av]' -map '[aud]' -t 5 -c:v libx264 -c:a aac -metadata:s:a:0 language=eng -metadata:s:a:0 title="aevalsrc" -metadata:s:a:1 language=eng -metadata:s:a:1 title="anoisesrc" -f mp4 -y noise.mp4 

ffmpeg -f lavfi -i nullsrc=s=640x480 -filter_complex 'geq=random(1)*255:128:128;aevalsrc=-2+random(0)[av],anoisesrc=d=5:c=pink:r=44100:a=0.5[aud]' -map '[av]' -map '[aud]' -t 5 -c:v libx264 -c:a aac -metadata:s:a:0 language=eng -metadata:s:a:0 title="aevalsrc" -metadata:s:a:1 language=eng -metadata:s:a:1 title="anoisesrc" -f matroska -y noise.mkv

ffprobe -report -show_streams noise.mkv > MKV.ffprobe.output

ffprobe -report -show_streams noise.mp4 > MP4.ffprobe.output

grep TAG MKV.ffprobe.output MP4.ffprobe.output 

Note that if you play the mp4 file in VLC (or elsewhere), both audio tracks show as properly titled -- it seems that ffmpeg is properly writing the mp4.

last tried ffprobe N-91565-g1940c27c82-tessus, obtained today

[T]

FWIW the only cli tool I can find that correctly finds & reports the titles is a macOS tool called sublercli. And sublercli omits the language tag.

Eg:
sublercli -listtracks -source noise.mp4