When I listen to YouTube videos in Firefox, they are noticeably quieter and less full-sounding than when I listen to them in Chromium. It’s as if Google is sending them at different volumes because they’re sending differently encoded videos because they can use codecs which they prefer in Chromium but can’t for Firefox or something. I don’t want to turn up my system/Firefox volume in general because just YouTube is quieter (Soundcloud is the same volume on both Firefox and Chromium, so I’m certain that my system volume settings are correct and shouldn’t be changed). Maybe I need to give Firefox permission to use more codecs from the OS? How would I do this? Is it YouTube’s fault? I'm using Windows 10 and Firefox 56.0b10 64-bit. However, I’ve always noticed this problem for at least over a half year, it isn’t specific to this version of Firefox. EDIT: I though this was all videos, but I found one where the sound is the same between Chromium and Firefox. For example, https://www.youtube.com/watch?v=v1uSlrukwHY which sounds just as loud in Firefox as in Chromium. An example of a video which is quieter in Firefox is https://www.youtube.com/watch?v=1aOc_8uzS2Y (and most other videos I view). Maybe there’s something different between those videos that gives a hint?