Sadly, I was having a lot of issues implementing the ability to save the volume per page, and most videos on a page are diferent volume anyways so this is not a planned feature.

The volume should not be able to move on its own, but when the popup.htm is opened, the slider is highlighted. So if you're in windows for example and have a controller plugged in, it interacts with the slider so controller drift can be an issue in that case. But otherwise I asusme your issue is not the extension itself but the videos you're watchin/diferent scenes being diferent volume. In which case you'd want a normalizer. But I don't think there's a way to do it in chromium rather you should use third party application for example I have a python one in progress which is published in my github for windows....

Please tell me what site....
If you read the description, assigning permission to allow all urls in the permission options allows it to work on more sites.
Help me, help you, why just leave a negative review? It's open source and I do this as a hobby (I get nothing from it) and have spent countless hours working on it, so it's painful to see a negative review with no way of remedying it.