Can someone please explain CMTime for iOS4?

I would like to use AVPlayer C开发者_如何学Class' seekToTime. It takes a CMTime. I read the CMTime reference from Apple but its is very hard to understand. Can someone please give me an example on how to use...

- (void)seekToTime:(CMTime)time

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Some example are provided in the AV Foundation Programming Guide such as:

CMTime fiveSecondsIn = CMTimeMake(5, 1);
[player seekToTime:fiveSecondsIn];