Fix some issues with looping videos, and videos added in tiny chunks

This improves:
 * Valkyrie Profile, which both no longer hangs and displays its videos now.
 * Burnout Legends, which no longer has the video "stall" if you wait a little bit (possibly any games logging [that same error may be improved] (http://report.ppsspp.org/logs/kind/178).)

I tested the usual suspects (especially Wipeout Pure) and none seemed to have problems.  May help other games hanging on video or displaying black instead of video.

-[Unknown]