YouTube Music Practice Looper by Laurent G

Advanced practice tool for musicians: independent speed/pitch control, beat-synced A/B looping, tap tempo, and visual beat grid. Perfect for slowing down difficult passages while maintaining pitch.
YouTube Music Practice Looper is designed specifically for musicians who want to practice along with YouTube videos. Whether you're learning guitar solos, transcribing jazz lines, or mastering complex drum patterns, this extension gives you practice features.

Created by an amateur developer and musician who wanted better practice tools for YouTube videos, this extension is given to the music community to help fellow musicians practice more effectively. - completely free, no ads, no tracking.

Key Features
🎵 Independent Speed & Pitch Control
🔁Beat-Synced A/B Looping
Set precise loop points that snap to musical beats. Very useful. Always start your loop on the beat !
⏱️ Tap Tempo
📊 Visual Beat Grid (only relevant for 4/4 time signature
⌨️ Keyboard Shortcuts
💾Per-Video Settings
All your settings are automatically saved for each video

Perfect For

Guitar players learning solos and complex riffs
Drummers working on intricate patterns and fills
Bass players transcribing bass lines

How to Use

Enable the extension - Click the toolbar icon (disabled by default)
Open any YouTube video - The control panel appears in the bottom-right
Set the tempo - Press T repeatedly on each beat to detect BPM
Mark your loop - Press A at the start, B at the end of the section you want to practice
Start practicing - Press L to loop, adjust speed with [ and ] keys
Fine-tune - Use Q/W/E/R to move markers by beat for perfect alignment

Perfect for
Pianists mastering difficult passages
Vocalists learning melodies and harmonies
Music students transcribing and analyzing music
Music teachers preparing lesson materials
Anyone wanting better control over YouTube playback

Privacy & Permissions
This extension does NOT collect any data. All settings are stored locally in your browser. The only permissions requested are:

Storage - To save your settings per video
ActiveTab - To work with YouTube videos

No telemetry, no analytics, no data sent anywhere. Your practice sessions are completely private.
Technical Details

Works only on YouTube.com
Requires Firefox 109 or later
Off by default - click toolbar icon to enable
Lightweight and fast
No external dependencies

icon found here :
https://www.flaticon.com/free-icons/audio-tape