On Firefox (Quantom for Testing) Video stops after 1 second and stops buffering MSE

[cyberpunkbln]

Hello,

under Firefox/Windows the video test.webm stops the buffering after 1 second and hang in the load circle.
When i reduce the NUM_CHUNKS Size its play more seconds and when i reduce it to 1 the whole video plays.

InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable main.js:64
	readChunk_/reader.onload https://simpl.info/mse/js/main.js:64:9

Under Chrome its functioned well.

When i want to use an mp4 it don't start playing, by the way.

thx

ps: How do you convert ore create your webm that it is streamable as an blob with MSE?