Stem Quality Judgment¶
Flag: --choose-stems
Suno exports numbered stems, but their quality varies — some have audible bleed, phase issues, or missing frequency content. When --separate-missing generates AI stems via Demucs or UVR, you now have two versions of each stem. This feature helps you pick the better one.
What it evaluates¶
- Is Suno's provided stem good enough? Compares RMS energy, spectral centroid, and silence ratio to detect thin or empty stems.
- Is the Demucs output better than the original? Computes normalized cross-correlation between both versions, then scores on silence ratio and energy to recommend the cleaner one.
- Replace one stem or all? Reports per-stem with individual confidence scores, so you can swap only the bad ones instead of throwing out Suno's work wholesale.
When to use it¶
- After running
--separate-missingto generate AI stems alongside the originals - When you hear bleed or phasing in a specific stem and want a data-backed second opinion
- When you want to automate "listen to both, pick the better one" across a batch of songs
Example¶
What --apply does¶
Without --apply, prints a comparison report. With --apply, copies the recommended stem into the output directory, replacing the weaker version.