https://www.reddit.com/r/firefox/comments/zeg2qy/firefox_doesnt_support_h265_hevc_for_patent/
Discussion
Try to play this on chrome under Linux:
https://www.bitbubblex.com/uploads_qsa67WW2_Ju12_55gddG34/4ce62139c3b06d652c5623142c2d9cfc.mp4
It won't play either. However VLC plays everything nicely. All because of the H.265 issue.