Create backing tracks for your open mic or karaoke night

_README.md

Create backing tracks for your open mic or karaoke night

If you want a UI, check out https://github.com/stemrollerapp/stemroller.

Summary

The steps are:

• Download your song (could be done with yt-dlp)
• Install demucs and ffmpeg
• Separate the track with demucs
• Join the drums/bass/other tracks with ffmpeg into a track that you can use as your backing track!

For example I'll create a backing track with drums/bass for the song Amarte sin Amarte by Jr, first let's download the song:

yt-dlp -x --audio-format mp3 "https://www.youtube.com/watch?v=pG7IS0lFPt4"
[youtube] pG7IS0lFPt4: Downloading webpage
[youtube] pG7IS0lFPt4: Downloading player 2fd212f2
[download] Destination: Amarte Sin Amarte-pG7IS0lFPt4.webm
[download] 100% of 3.45MiB in 00:48
[ffmpeg] Destination: Amarte Sin Amarte-pG7IS0lFPt4.mp3
Deleting original file Amarte Sin Amarte-pG7IS0lFPt4.webm (pass -k to keep)

Next let's use demucs to separte the track into different instrument tracks, I didn't have to play with flags for it to work perfectly.

 demucs "Amarte Sin Amarte-pG7IS0lFPt4.mp3"
Selected model is a bag of 4 models. You will see that many progress bars per track.
Separated tracks will be stored in ./separated/mdx_extra_q
Separating track Amarte Sin Amarte-pG7IS0lFPt4.mp3
100%|████████████████████████████████████████████████████████████████████████| 231.0/231.0 [01:03<00:00,  3.66seconds/s]
100%|████████████████████████████████████████████████████████████████████████| 231.0/231.0 [01:03<00:00,  3.66seconds/s]
100%|████████████████████████████████████████████████████████████████████████| 231.0/231.0 [01:05<00:00,  3.53seconds/s]
100%|████████████████████████████████████████████████████████████████████████| 231.0/231.0 [01:03<00:00,  3.61seconds/s]

Finally let's join the drum/bass tracks with ffmpeg, the separated tracks are in ./separated/md_extra_q, the combined file is combined.wav.

cd separated/mdx_extra_q/Amarte\ Sin\ Amarte-pG7IS0lFPt4/
ffmpeg -i bass.wav -i drums.wav -filter_complex amix=inputs=2:normalize=0 combined.wav

Finally let's convert again to mp3 for the open mic

ffmpeg -i combined.wav -vn -ar 44100 -ac 2 -b:a 192k amarte-sin-amarte--bass-drums.mp3

Known issues

ERROR: WARNING: unable to obtain file audio codec with ffprobe

Run brew upgrade ffmpeg ytdl-org/youtube-dl#12367