我正在尝试使用合并多个视频AVMutableComposition
。我面临的问题是,每当我尝试添加任何AVMutableVideoComposition
为了应用任何指令,我的播放冻结在AVPlayer
持续时间正好 6 秒。
另一个有趣的事情是,如果我在使用相同的导出后在 iPad 的照片应用程序中播放它,它会播放得很好videoComposition
。那么为什么它会冻结AVPlayer
6秒?
Code:
AVMutableComposition *mutableComposition = [AVMutableComposition composition];
AVMutableCompositionTrack *videoCompositionTrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeVideo
preferredTrackID:kCMPersistentTrackID_Invalid];
AVMutableCompositionTrack *audioCompositionTrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeAudio
preferredTrackID:kCMPersistentTrackID_Invalid];
for (AVURLAsset *asset in assets)
{
AVAssetTrack *assetTrack;
assetTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
AVAssetTrack *audioAssetTrack = [asset tracksWithMediaType:AVMediaTypeAudio].firstObject;
NSError *error;
[videoCompositionTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, assetTrack.timeRange.duration )
ofTrack:assetTrack
atTime:time
error:&error];
if (error) {
NSLog(@"asset url :: %@",assetTrack.asset);
NSLog(@"Error1 - %@", error.debugDescription);
}
[audioCompositionTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, audioAssetTrack.timeRange.duration)
ofTrack:audioAssetTrack
atTime:time
error:&error];
if (error) {
NSLog(@"Error2 - %@", error.debugDescription);
}
time = CMTimeAdd(time, assetTrack.timeRange.duration);
if (CGSizeEqualToSize(size, CGSizeZero)) {
size = assetTrack.naturalSize;;
}
}
AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
AVMutableVideoCompositionLayerInstruction *videoTrackLayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoCompositionTrack];
mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, time);
mainInstruction.layerInstructions = [NSArray arrayWithObjects:videoTrackLayerInstruction, nil];
AVMutableVideoComposition *mainCompositionInst = [AVMutableVideoComposition videoComposition];
mainCompositionInst.instructions = [NSArray arrayWithObject:mainInstruction];
mainCompositionInst.frameDuration = CMTimeMake(1, 30);
mainCompositionInst.renderSize = size;
pi = [AVPlayerItem playerItemWithAsset:mutableComposition];
pi.videoComposition = mainCompositionInst;
另外,我知道问题主要是videoComposition
因为如果我删除videoComposition
,然后它就可以正常运行AVPlayer
.
UPDATE 1:我刚刚发现,当它在 6 秒后冻结时,如果我向后或向前拖动滑块(即使用seekToTime
),它再次开始正常播放,不再卡顿。
即使视频冻结,音频也能正常播放。
UPDATE 2:如果我继续使用AVAssetExportSession
与相同AVMutableComposition
,并从导出的视频加载资源,效果很好。所以只是当我玩的时候AVMutableComposition
直接,问题就出现了。