Volume gradually decreases on YouTube when playing next video in playlist (Firefox)

[maelkashishi]

When playing a YouTube playlist or a “jam” (autoplay), the volume slider decreases slightly with each subsequent video. After several videos, the volume eventually drops to zero. The issue occurs even though YouTube’s built-in “Stable Volume” feature is disabled.

Environment

Browser: Firefox (tested on recent versions)

Extension: Volume Control (https://github.com/Abev08/VolumeControlExtension)

YouTube settings: “Stable Volume” is turned off

Additional context
The problem disappears completely when the extension is disabled, confirming that the extension is the cause.

[Abev08]

Hey, thanks for reporting the issue.
I wasn't able to reproduce the described issue.
But from what I have tested it didn't really work on YouTube Shorts. I have pushed an update to the extension that mostly fixes functionality - it works when you scroll the shorts down (99% of people does that) but breaks when you scroll up.
Could you update the extension and test if that fixes your issue?

[maelkashishi]

Thank you for the update! I’ve updated the extension and tested it with playlists and autoplay (jams). The volume no longer decreases with each video. It looks like the issue is fixed.

If I notice anything else, I’ll let you know. Thanks again!

[maelkashishi]

After updating to the latest version (which fixed the previous issue with gradual volume decrease in playlists), I’ve noticed a new problem:

The native volume slider on YouTube no longer affects the audio level.

I can only change the volume using the extension’s own controls (icon in the toolbar).

This happens on all YouTube pages (regular videos, playlists, etc.).

Steps to reproduce:

Install the latest version of the extension in Firefox.

Open any YouTube video.

Try to adjust the volume using YouTube’s built‑in slider (the one that appears when you hover over the video).

Observe that the volume does not change, regardless of the slider position.

Adjust the volume using the extension’s popup – the volume changes as expected.

Expected behavior:
Both the extension’s volume control and YouTube’s native slider should work, or at least the native slider should remain functional.

Actual behavior:
YouTube’s native volume slider has no effect; only the extension can change the volume.

Environment:

Browser: Firefox (latest)

Extension: Volume Control (the version that includes the recent fix for playlists)

YouTube settings: Stable Volume off

Additional context:
The issue started immediately after updating to the version that addressed the playlist volume decrease. Disabling the extension restores normal YouTube volume control.

[Abev08]

Sorry for the inconvenience. I pushed update that hopefully should fix the volume change issue.

About the slider not changing, it's hard to change it programmatically and it not being updated doesn't seem to affect the volumes so I figured that not doing anything to it is ok. More testing is needed.