No video with supported format and MIME type found
Assuming you used ffmpeg to process the video, you can probably fix this by adding -pix_fmt yuv420p to your ffmpeg invocation: https://stackoverflow.com/a/24468585
@99991 thanks for reporting this bug!
We didn't know Firefox doesn't support HEVC encoding, sorry... We've changed our video to H.264, and it should work on Firefox now!
On Firefox, the video on your demo page says
Assuming you used ffmpeg to process the video, you can probably fix this by adding
-pix_fmt yuv420p
to your ffmpeg invocation: https://stackoverflow.com/a/24468585