corrupted frames when capturing with uvccapture

[Raffaella Traniello]

PROBLEM:
When grabbing with uvccapture from webcam, occasionally (especially at high framerate) the live preview is flickering. Some grabbed frames are grey in full or in part. The saved images are corrupted.

CAUSE:
uvccapture overwrites the file in-place. Since Stopmotion reads the capture file asynchronously, it will sometimes read a partially overwritten file, hence the partially gray image.

SOLUTION:
uvccapture should rather write to a temporary file first, then rename it, so the capture file instantly changes from one image to the next.

uvccapture patch by Herman Robak coming soon.