我正在尝试使用AVAssetExportSession合并(追加)3个视频,但我一直收到此错误.奇怪的是它有1或2个视频.
Error Domain=AVFoundationErrorDomain Code=-11820 "Cannot Complete Export" UserInfo=0x458120 {NSLocalizedRecoverySuggestion=Try exporting again.,NSLocalizedDescription=Cannot Complete Export}
我甚至尝试重做函数以防出错,但我得到的只是无限错误信息.这是我的代码的片段.
AVMutableComposition *mixComposition = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
NSError * error = nil;
NSMutableArray * timeRanges = [NSMutableArray arrayWithCapacity:arrayMovieUrl.count];
NSMutableArray * tracks = [NSMutableArray arrayWithCapacity:arrayMovieUrl.count];
for (int i=0; i<[arrayMovieUrl count]; i++) {
AVURLAsset *assetClip = [arrayMovieUrl objectAtIndex:i];
AVAssetTrack *clipVideoTrackB = [[assetClip tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
[timeRanges addObject:[NSValue valueWithCMTimeRange:CMTimeRangeMake(kCMTimeZero,assetClip.duration)]];
[tracks addObject:clipVideoTrackB];
}
[compositionTrack insertTimeRanges:timeRanges ofTracks:tracks atTime:kCMTimeZero error:&error];
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPreset1280x720];
NSParameterAssert(exporter != nil);
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.outputURL = outputUrl;
[exporter exportAsynchronouslyWithCompletionHandler:^{
switch ([exporter status]) {
case AVAssetExportSessionStatusFailed:
NSLog(@"Export Failed: %@",[exporter error]);
break;
case AVAssetExportSessionStatusCancelled:
NSLog(@"Export canceled");
break;
case AVAssetExportSessionStatusCompleted:
NSLog(@"Export successfully");
break;
default:
break;
}
if (exporter.status != AVAssetExportSessionStatusCompleted){
NSLog(@"Retry export");
[self renderMovie];
}
}];
解决方法
我发现了问题.所以问题实际上是因为我使用AVPlayerLayer同时以预览模式显示每个视频.参考这个问题
AVPlayerItem fails with AVStatusFailed and error code “Cannot Decode”,有最大4个同步AVPlayer的无证限制.当这个时刻有4个AVPlayer实例时,这个限制会以某种方式阻碍AVAssetExportSession的工作.
解决方案是在导出之前释放AVPlayer,或者完全不使用AVPlayer.
