MP4 AV1

[Emmdg]

macOS version: Big Sur: 11.5.2 (20G95).
Kap version: Version 3.3.2 (3.3.2.1718).
Issue: I was doing and screen recording of: 5seconds and when I clicked export: this option was default: MP4 AV1: I clicked EXPORT but the video couldn't be exported, the ventilators of my iMac started to sound.

Workaround: I quitted the app, opened it up again, then I changed the option to export to: MP4-264, and the video was abel to be exported.

I don't know if this is normal or not, but i hope you can take a look at it.

[skllcrn]

Closing in favor of #939