Based on
https://ffmpeg.org/pipermail/ffmpeg-user/2024-March/057775.html
loudnorm is a low quality filter.
Some research gave some alternatives.
One of these is "pyloudnorm", a native python module implementing
EBU R 128 loudness normalization.
This is what I have implemented now instead of the old ffmpeg
filter.
In the future additional rewrites to use the official FLAC and OPUS
encoders might be desirable for better compression.
- Implement different conversions for lossless and lossy sources
- Remove unused functions
- Cleanup comments
I noticed that FLAC --> FLAC normalisation will change the bit depth
from 16 to 24. Wasn't able to find a simple solution for it, so I
asked on the ffmpeg-user mailing list
https://ffmpeg.org/pipermail/ffmpeg-user/2024-March/057774.html