Zack Design has published audio-analysis-and-recut — a small Python + FFmpeg pipeline that takes a noisy live performance recording, works out exactly which sections of the original studio track the band played, and generates a high-fidelity recut that follows the live arrangement.

The problem

You have two audio files:

• Original — the studio recording. High fidelity, the version on Spotify, the one you actually want to listen to.
• Performance — a live recording of the same song. Great arrangement, maybe some improvisation, but also crowd noise, ambient PA colouration, and a phone mic’s idea of bass response.

The live arrangement is better — it is the one the band actually performed — but the audio fidelity is worse. What you want is: the live arrangement, with studio fidelity. That is what this tool does.

How it works

1. Band-pass filter to 200–4000 Hz on both tracks. Vocals live in that range, crowd noise and room rumble largely do not. This is what makes matching robust to a noisy live environment.
2. Sliding-window cross-correlation between chunks of the performance and the full studio track. Each chunk’s best match pins down where in the original it came from.
3. Segment detection by grouping matches with consistent time offsets. A 30-second verse played live will produce 30 seconds of chunks that all agree on the same studio offset.
4. FFmpeg concatenation of the identified original segments, in the order the live performance used them, into a clean output file.

Example output

For “Ya Te Olvide” by Los 4 ft Laritza Bacallao (4:40 studio original → 1:56 live performance):

SEGMENT MAP:
  1  0:00-0:19  |  Orig 0:12-0:30  |  18.5s  (intro/verse start)
  2  0:19-1:04  |  Orig 0:50-1:35  |  44.5s  (verse/chorus)
  3  1:04-1:36  |  Orig 2:44-3:15  |  31.5s  (montuno section)
  4  1:36-1:46  |  Orig 4:13-4:23  |   9.5s  (ending)
  5  1:46-1:48  |  Orig 4:33-4:35  |   2.0s  (final tag)

Skipped from original:
  0:00-0:12  (11.8s) - pre-intro
  0:30-0:50  (20.1s) - transition/repeat
  1:35-2:44  (69.1s) - repeated verse section
  3:15-4:13  (57.9s) - extended montuno/breakdown
  4:23-4:33  (10.3s) - outro padding

The segment map reads like a director’s cut list: the band skipped the pre-intro, compressed the long breakdown, and landed on a different ending. Feeding that back into FFmpeg reconstructs the performance from clean studio audio.

Why bother

Latin dance classes like Havana on the Hastings often rehearse to studio recordings but perform to the band’s own arrangement — which means choreographies that work in rehearsal do not always align with the live record they are showcased against. A recut reconciles the two: same arrangement the dancers know, but clean enough to cue on.

Usage

cp original_song.mp3 staging/original.mp3
cp performance_recording.mp3 staging/performance.mp3
python3 analyze.py
# Output: output/ya_te_olvide_recut.mp3

Dependencies are Python 3 with NumPy, plus a working FFmpeg on $PATH. Source on GitHub.