"Unable to access microphone" misleading error, OBS camera no longer works

[MadMartian]

Steps to reproduce

1. Start OBS and then start the virtual camera
2. Start Element and change the video camera to the OBS virtual camera
3. Try to place a call, either video or audio, from Element Desktop.

This isn't a problem from Element mobile or from another user, it seems to be unique to Element-Desktop on Ubuntu 22.04 with OBS.

Placing calls seems to work if I do not use OBS.

Outcome

"Unable to access microphone" error message pop-up. Upon opening the developer console this is the underlying error:

rageshake.ts:69 Call 1761186345533RsMcUfL5AWMucXlr getUserMediaFailed() failed to get user media - ending call NotReadableError: Could not start video source
rageshake.ts:69 Call error: k: Couldn't start capturing media! Is your microphone set up and does this app have permission?: NotReadableError: Could not start video source
    at A.getUserMediaFailed (call.ts:2227:13)
    at A.placeCall (call.ts:2835:18)
    at async A.placeVideoCall (call.ts:485:18)

The end-user error message implicates my microphone but this error message implicates my video device. I do not have any trouble with my video device + OBS virtual camera as I use it regularly for MS Teams, Zoom, OBS, and Discord.

This was working up until a few weeks ago.

Operating system

Ubuntu 22.04

Application version

Element version: 1.12.2 Crypto version: Rust SDK 0.14.0 (c3b7918), Vodozemac 0.9.0

How did you install the app?

I think a Debian package, can't remember, I've had it installed for years.

Homeserver

Synapse 1.118.0

Will you send logs?

Yes