小编Sah*_*har的帖子

首先,我要说我喜欢这个论坛,它帮助了我很多时间.我有一个问题,我无法在任何地方找到答案,所以这是我的第一个问题.

我的问题是:

我有一个由AVPlayerItem表示的视频,用户可以使用cutBefore按钮编辑视频开始时间,该按钮将视频剪切到滑块的左侧

负责剪切视频的方法如下:

- (void)CutBeforeAction { 

AVMutableComposition *composition = [AVMutableComposition composition];

// Get the audio and video tracks of the video
AVMutableCompositionTrack *compositionVideoTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVMutableCompositionTrack *compositionAudioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

// Calculate the new duration
CMTime currStartTime = _player.currentItem.currentTime;
CMTime endTime = _player.currentItem.duration;
CMTimeRange range = CMTimeRangeFromTimeToTime(currStartTime, endTime);

// Insert the new duration to the tracks
NSError *error = nil;
[compositionVideoTrack insertTimeRange:range 
                               ofTrack:[[_player.currentItem.asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]
                                atTime:kCMTimeZero
                                 error:&error];

[compositionAudioTrack insertTimeRange:range 
                               ofTrack:[[_player.currentItem.asset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0]
                                atTime:kCMTimeZero
                                 error:&error];
// Create …