That's what I'm here trying to figure out. If I play from USB, the audio and video is always out of sync.
In fact if I play a video off the hard drive and pause & resume it too much, it will also, eventually go out of sync.
What hardware you using?
Well, what kind of video, what resolution/format/bitrate? If you play 720p H264 stuff on a 1.25GHz machine, it will be a bit too short, and thus go out of sync (unless you enable framedrop, but it doesn't help a lot in this case).
Playing a video from USB can add a slight overhead, but unless you get a really low transfer speed or that you play a too demanding movie, it shouldn't matter. At least it doesn't here, even on my peg2 with usb1 (as long as the bitrate is below the usb1 transfer speed

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