audio/video time shifting

[edwardsharp]

It would be neat if there was a way to time-shift the audio/video for some videos, particularly lyric videos that show lyrics in realtime. This way the lyrics (video) would be shown earlier so as to be more karaoke-like.

One way to do this would be to mute the main player audio and setup a nudge forward (or backward) button the adjust the play position and let the audio flow out of the preview player in the main app's queue.