Problem here is unless a FB user with the same version of Chrome or firefox that your using go to the same link or site - finding the problem will be hard to know. Login sites are particular problem since it requires those with login access to see where the problem is happening.

deanyzg said

I uploaded my music video on Facebook. When I play the same video 720p over Mozilla and Chrome the results are totally different. Audio quality on Mozilla is much worse than Chrome. How to fix this? On Chrome the audio is more crisp and it's the same like on my computer recorded audio. On Mozilla audio is muffled and poor quality. How to fix this?

+There isn't 1080p option to choose like in Chrome