How to get the total time of all video playback on the iPhone?

No, the process of playing a video playback time, all the video, was a total playing time;
QQ housekeeper software can be achieved, I do not know how, thanks.
Reply:
@ Property (readonly) NSTimeInterval duration; / * the duration of the sound * /.
Reply:

cited a floor ybh37 reply:

@ property (readonly) NSTimeInterval duration; / * the duration of the sound * /

This is not what I want is to get: Iphone mobile phone on a player who had all of video length, not the total length of the video.
Reply:
The total length of all the video playback? The right to write their own methods. . . Each time the player plus one together!