This is somewhat similar to an already open issue. I am on 25032014 nightly of CM11 on i9300. When I switch to front camera and try to record the video, the screen gets pixelated and kaleidoscopic. The recorded video however is OK.
Open Camera v1.9
Android API version: 19
Standard max heap? (MB): 64
Large max heap? (MB): 256
Display size: 720x1280
Current camera ID: 1
Preview resolutions: 1280x720, 960x720, 640x480, 320x240, 704x704, 320x320
Photo resolutions: 1280x960, 1392x1392, 640x480, 1280x720, 720x480, 320x240
Video quality: 4, 2
Auto-stabilise?: Available
Face detection?: Available
Flash modes: None
Focus modes: focus_mode_infinity, focus_mode_fixed
Color effects: none, mono, negative, sepia, solarize, posterize, washed, vintage-warm, vintage-cold, point-blue, point-red-yellow, point-green
Scene modes: None
White balances: auto, incandescent, fluorescent, daylight, cloudy-daylight
Anonymous
Thanks for the report. Unfortunately I don't have any CM11 devices to test with, but a video corruption bug for some devices was fixed in version 1.10 onwards, so please try with the latest version, and let me know if it's still an issue.