Question

我想将视频导出3次以上原创（同一视频重复3次）。这意味着2秒的视频将是6秒。那怎么可能呢？

我已经实现了导出视频并将其保存在cameraroll中。所以请告诉我最好的方法是什么。

Answer 1

AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];

/*******************Code for increase video length*****************************************/

AVAssetTrack *clipVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:clipVideoTrack atTime:kCMTimeZero error:nil];
CMTime videoLength = videoAsset.duration;
if(self.isVideo){
    [compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:clipVideoTrack atTime:videoAsset.duration error:nil];
    videoLength = CMTimeAdd(videoAsset.duration, videoAsset.duration);
}
[compositionVideoTrack setPreferredTransform:[[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] preferredTransform]];

//slow down whole video by 2.0
double videoScaleFactor = scalfactor;
CMTime videoDuration = videoLength;
[compositionVideoTrack scaleTimeRange:CMTimeRangeMake(kCMTimeZero, videoDuration)
                           toDuration:CMTimeMake(videoDuration.value/videoScaleFactor, videoDuration.timescale)];

CGSize videoSize = [clipVideoTrack naturalSize];

/******************* End Code *************************************************************/

如何将视频长度设置为原来的3/4倍？

1 个答案: