Question about blocking audio/video during autoplay (Linux)

[tomdkat]

Hi! Today, I noticed strange behavior in Firefox 70.0.1 on Ubuntu 18.04.3 while watching YouTube videos. She noticed she wasn't getting any audio while watching a YouTube video. This was due to my setting up Firefox to block audio when videos autoplay. Cool. So, I changed that setting to allow audio/video when videos autoplay. I made this change while on YouTube. After making that change, I still didn't get audio from any YouTube videos. So, I closed Firefox and re-opened it. Went back to YouTube and audio was restored. Groovy.

So, I changed Firefox to block video/audio when videos autoplay, closed Firefox, and re-opened it. I opened a YouTube video, it automatically started playing, and I heard the audio *despite* Firefox being configured to block audio/video. So, I changed Firefox back to allowing audio/video when videos autoplay.

Any ideas on why YouTube videos, that autoplay, will still have audio that's audible even though Firefox is set to block audio during autoplay?

I've encountered this only on YouTube (so far).

Thanks in advance!

Peace...