我已经设置了一个AVAssetExportSession只有 2 个音频轨道，没有视频，它的播放就像我想要的那样AVPlayer- 但是当我去导出它时，唯一可用outputFileType的是AVFileTypeQuickTimeMovie- 为什么我不能选择音频格式？
当我NSLog(@"%@", [session supportedFileTypes]);得到；
[51330:c07] (
"com.apple.quicktime-movie"
)
这是我的代码；
- (AVMutableComposition *)getComposition {
AVAsset *backingAsset = [AVAsset assetWithURL:self.urlForEightBarAudioFile];
AVAsset *vocalsAsset = [AVAsset assetWithURL:self.recorder.url];
AVMutableComposition *composition = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionBackingTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
AVMutableCompositionTrack *compositionVocalTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *backingAssetTrack = [backingAsset.tracks objectAtIndex:0];
AVAssetTrack *vocalsAssetTrack = [vocalsAsset.tracks objectAtIndex:0];
CMTimeRange timeRange = CMTimeRangeFromTimeToTime(kCMTimeZero, backingAsset.duration);
[compositionBackingTrack insertTimeRange:timeRange ofTrack:backingAssetTrack atTime:kCMTimeZero error:nil];
[compositionVocalTrack insertTimeRange:timeRange ofTrack:vocalsAssetTrack atTime:kCMTimeZero error:nil];
return composition;
}
- (IBAction)acceptRecording:(id)sender {
AVAssetExportSession * session = [[AVAssetExportSession alloc] initWithAsset:[self getComposition] presetName:AVAssetExportPresetMediumQuality];
NSURL *output = [self.urlForPathToEightBarRecordings URLByAppendingPathComponent:@"mix.mov"];
session.outputURL = output;
session.outputFileType = AVFileTypeQuickTimeMovie;
NSLog(@"%@", [session supportedFileTypes]);
[session exportAsynchronouslyWithCompletionHandler:^() {
switch (session.status) {
case AVAssetExportSessionStatusCompleted:
NSLog(@"It's done...hallelujah");
break;
default:
break;
}
}];
}