This works great but there are instances where it doesn't work

[PacoH]

This works great but there are instances where it doesn't work

It doesn't work for waveform generation. Maybe it's because showwavespic does not normally show any progress statistics.

e.g.,

ffmpeg -i "$nwn" -f lavfi -i color=c=#127897:s=${s} -filter_complex \ "aformat=channel_layouts=mono,showwavespic=s=${s}:colors=#00FF00[fg];[1:v][fg]overlay=format=auto" -frames:v 1 "$ng"

The bar remains at zero until the end.

First pass of a two-pass sequence. It fails to run at all.

e.g.,

af="loudnorm=I=-16:TP=-1.5:LRA=11:print_format=json" ffmpeg-bar -i "$f" -map $track -vn -sn -dn -af "$af" -f null - 2>&1