macOS camera recording produces empty 0-byte camera.mp4 while the live preview works #2116

Cap version: 0.5.9 (latest)
macOS: 14.8.8
Camera: iphone 11 pro

Expected:
Camera track should be recorded.

Actual:
The preview works, Cap receives frames, but camera.mp4 is 0 bytes.

Relevant recording log:
Cap initializes the camera encoder at 1280x720, but frames arrive at 1920x1080:
Frame dimension mismatch, dropping frame to protect writer
expected_width=1280 expected_height=720
frame_width=1920 frame_height=1080

Then:
Failed to finish camera MP4 encoder: NotWriting

ARZOPA 08.24 PM — camera-missing.log
ARZOPA 10.38 PM — camera-missing.log
ARZOPA 10.39 PM — camera-missing.log

This happens consistently in multiple recordings.