Massively degrades mp3 audio quality

[julcst]

Bug Description

I tested it using docker on a MacBook on some CC0 music and it introduces heavy bitcrushing on any mp3 I tried:

Original: https://cdn.openmusic.academy/media-library/elevator-ride-jazz-TNt2J7FHHRrPRa3nCYNJQc.mp3

Stem separated: https://github.com/user-attachments/assets/e167fea5-8dba-4e7b-9fb2-15cf4635990d

Version

latest

OS

macOS - Docker

[acolombier]

Hey @julcst - first thing that strikes me is the original file uses a 48kHz sampling rate, and demucs models are trained with 44100 Hz, so I'm wondering if the resampling (that stemgen is supposed to take care of!) is somehow introducing some problems. I'll try to investigate that.

[acolombier]

Unfortunately, I wasn't unable to reproduce this with the latest version on Linux and don't have a Mac to test if this would be OS-specific

Here is the file I get as a result, which appears to not suffer from any audible alterations:

elevator-ride-jazz-TNt2J7FHHRrPRa3nCYNJQc.stem.mp4

Could you please give it a go with aclmb/stemgen:main?