As of commit c582be4c38596a6a31a39c6799723dcd8b6eb909 (Sept. 23),
ungoogled-chromium fails to grab images from my webcam (for instance in
BigBlueButton instances), printing this message repeatedly:
[4685:3:0924/102919.814053:ERROR:video_stream_encoder.cc(1762)] Failed to encode frame. Error code: -7
I found that an older generation (Aug. 30) works for me:
guix time-machine --commit=f91ae9425bb385b60396a544afe27933896b8fa3 -- \
environment --ad-hoc ungoogled-chromium -- chromium
The regression must have been in between these two commits.