ios – AVFoundation AVMutableComposition – 带音频的视频 – 冻结视频

我有一个带声音的录制视频.将其添加到AVMutableComposition然后将其导出时,视频将在播放声音时冻结.我错过了什么？

我有两条曲目：

_compositionVideoTrack = [self.composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
_compositionAudioTrack = [self.composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

然后创建轨道：

AVAssetTrack *clipVideoTrack = [[sourceAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
AVAssetTrack *clipAudioTrack = [[sourceAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];

然后我插入曲目：

[_compositionVideoTrack insertTimeRange:editRange ofTrack:clipVideoTrack atTime:self.composition.duration error:&editError];
[_compositionAudioTrack insertTimeRange:editRange ofTrack:clipAudioTrack atTime:self.composition.duration error:&editError];

最后我导出它：

AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:urlAsset presetName:AVAssetExportPresetPassthrough];
exportSession.outputFileType = AVFileTypeQuickTimeMovie;

该文件是.mp4.它可能是文件格式吗？

解决方法

尝试使用以下导出

AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:self.inputAsset presetName:AVAssetExportPresetLowQuality];
    exportSession.outputFileType = AVFileTypeQuickTimeMovie;