[BUG] Generated video does not play in various browsers

[AmitMY]

Current Behavior

After playing a sign once, a video is generated. That video finishes, but does not play:

If I open the network, I see the video was downloaded. If I open the video in Safari, and ask for stats:

But this video also does not play in VLC.

AFAIK, this is the behaviour in desktop Safari, mobile Safari and mobile Chrome on iOS

Expected Behavior

video should play on all browsers and devices.

Same device, but using Chrome:

There should be a test to check this flow works on different browsers, periodically.

Steps To Reproduce

1. Open Safari
2. Open https://sign.mt
3. Write "test"
4. Wait for the sign to fully play once

[AmitMY]

Relevant issues:

• https://github.com/Vanilagy/webm-muxer/issues/32
• https://github.com/Vanilagy/mp4-muxer/issues/30

[AmitMY]

Confirmed, this is a safari bug experienced by many https://bugs.webkit.org/show_bug.cgi?id=245428

Possible solution: detect webkit, and use srcObject after fetching the blob, instead of src