I've been having "twitchy" playback on many, but not all videos. The video image oscillates between the following two states:
State A (rescaled, possibly single-frame):
State B (normal, several frames):
The random, scaled-down frames occur continually at brief, random intervals ranging from between about 0.5 s to 2 s. The behavior occurs only on the YouTube site; this video plays back normally embedded in an external site.
