ios - 添加水印后，AVMutableCompositionTrack始终将纵向视频旋转为横向

从最近两天开始，我用AVMutableCompositionTrack抓头，在我的情况下，它拍摄的是肖像视频，但是在添加水印后变成了风景。

这是我的代码:

AVURLAsset* videoAsset = [[AVURLAsset alloc]initWithURL:[[NSBundle mainBundle] URLForResource:@"Sample" withExtension:@".mp4"] options:nil];
AVMutableComposition* mixComposition = [AVMutableComposition composition];

AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo  preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *clipVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
                               ofTrack:clipVideoTrack
                                atTime:kCMTimeZero error:nil];

[compositionVideoTrack setPreferredTransform:[videoAsset preferredTransform]];

//WaterMark
UIImage *waterMark = [UIImage imageWithContentsOfFile:[[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"Sample.jpg"]];
CALayer *waterMarkLayer = [CALayer layer];
[waterMarkLayer setContents:(id)[waterMark CGImage]];
[waterMarkLayer setFrame:CGRectMake(30, 30, 100, 40)] ;
[waterMarkLayer setOpacity:0.8] ;

CGSize videoSize = [[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] naturalSize];
CALayer *parentLayer = [CALayer layer];
CALayer *videoLayer = [CALayer layer];
[parentLayer setFrame:CGRectMake(0, 0, videoSize.width, videoSize.height)];
[videoLayer setFrame:CGRectMake(0, 0, videoSize.width, videoSize.height)];
[parentLayer addSublayer:videoLayer];
[parentLayer addSublayer:waterMarkLayer];

//Instruction
AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
[instruction setTimeRange:CMTimeRangeMake(kCMTimeZero, [mixComposition duration])];
AVAssetTrack *videoTrack = [[mixComposition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

AVMutableVideoCompositionLayerInstruction* layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
[instruction setLayerInstructions:[NSArray arrayWithObject:layerInstruction]];

AVMutableVideoComposition *videoComp = [AVMutableVideoComposition videoComposition] ;
[videoComp setRenderSize:videoSize];
[videoComp setFrameDuration:CMTimeMake(1, 30)];
[videoComp setAnimationTool:[AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer]];
[videoComp setInstructions:[NSArray arrayWithObject:instruction]];

//Exporting File
NSString *fullMoviePath = [NSTemporaryDirectory() stringByAppendingPathComponent:[@"WaterMarkedMovie" stringByAppendingPathExtension:@"mp4"]];
NSURL *finalVideoFileURL = [NSURL fileURLWithPath:fullMoviePath];

AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];
[exportSession setOutputFileType:AVFileTypeMPEG4];
[exportSession setOutputURL:finalVideoFileURL];
[exportSession setVideoComposition:videoComp];

[exportSession exportAsynchronouslyWithCompletionHandler:^{

    switch ([exportSession status])
    {
        case AVAssetExportSessionStatusFailed:
        {
            NSLog(@"Export Failed: %@ %@", [[exportSession error] localizedDescription], [[exportSession error] debugDescription]);

            [[NSFileManager defaultManager] removeItemAtURL:[exportSession outputURL] error:nil];

            break ;
        }
        case AVAssetExportSessionStatusCancelled:
        {
            NSLog(@"Export Cancel: %@ %@", [[exportSession error] localizedDescription], [[exportSession error] debugDescription]);

            [[NSFileManager defaultManager] removeItemAtURL:[exportSession outputURL] error:nil];

            break ;
        }
        case AVAssetExportSessionStatusCompleted:
        {
            NSLog(@"Export Complete!");

            [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {

                if (status == PHAuthorizationStatusAuthorized)
                {
                    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
                        [PHAssetChangeRequest creationRequestForAssetFromVideoAtFileURL:[exportSession outputURL]];
                    } completionHandler:^(BOOL success, NSError *error) {

                        [[NSFileManager defaultManager] removeItemAtURL:[exportSession outputURL] error:nil];

                        if (success)
                        {
                            NSLog(@"Success");
                        }
                    }];
                }
                else
                {
                    NSLog(@"Not Authorised");

                    [[NSFileManager defaultManager] removeItemAtURL:[exportSession outputURL] error:nil];
                }
            }];

            break ;
        }
        default : NSLog(@"Default") ;
    }
}];

我已经尝试了所有看起来很重复的问题，但是Stackoverflow的任何解决方案都不适合我。

我必须保持其景观方向。我什至尝试在compositionVideoTrack和layerInstruction上设置转换，但它们都没有帮助我。

任何建议都会有所帮助。 :)

最佳答案

最后，我找到了解决方案，parentLayer和videoLayer的大小造成了问题。伴随着render.renderSize和layerInstruction转换也需要更改。这是代码:

AVURLAsset *videoAsset = [[AVURLAsset alloc]initWithURL:[[NSBundle mainBundle] URLForResource:@"Sample" withExtension:@".mp4"] options:nil];
AVMutableComposition* mixComposition = [AVMutableComposition composition];

AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo  preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *clipVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
                               ofTrack:clipVideoTrack
                                atTime:kCMTimeZero error:nil];

//WaterMark
UIImage *waterMark = [UIImage imageWithContentsOfFile:[[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"Sample.jpg"]];
CALayer *waterMarkLayer = [CALayer layer];
[waterMarkLayer setContents:(id)[waterMark CGImage]];
[waterMarkLayer setFrame:CGRectMake(30, 30, 100, 40)] ;
[waterMarkLayer setOpacity:0.8] ;

AVAssetTrack *assetVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] ;
CGSize videoSize = [assetVideoTrack naturalSize];

CALayer *parentLayer = [CALayer layer];
CALayer *videoLayer = [CALayer layer];
[parentLayer setFrame:CGRectMake(0, 0, videoSize.height, videoSize.width)];
[videoLayer setFrame:CGRectMake(0, 0, videoSize.height, videoSize.width)];
[parentLayer addSublayer:videoLayer];
[parentLayer addSublayer:waterMarkLayer];

//Instruction
AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
[instruction setTimeRange:CMTimeRangeMake(kCMTimeZero, [mixComposition duration])];
AVAssetTrack *videoTrack = [[mixComposition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

AVMutableVideoCompositionLayerInstruction* layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];

CGAffineTransform t1 = CGAffineTransformMakeTranslation(videoSize.height, 0);
CGAffineTransform t2 = CGAffineTransformRotate(t1, degreesToRadians(90.0));
[layerInstruction setTransform:t2 atTime:kCMTimeZero];
[instruction setLayerInstructions:[NSArray arrayWithObject:layerInstruction]];

AVMutableVideoComposition *videoComp = [AVMutableVideoComposition videoComposition] ;
[videoComp setRenderSize:CGSizeMake(videoSize.height, videoSize.width)];
[videoComp setFrameDuration:CMTimeMake(1, 30)];
[videoComp setAnimationTool:[AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer]];
[videoComp setInstructions:[NSArray arrayWithObject:instruction]];

//Exporting File
NSString *fullMoviePath = [NSTemporaryDirectory() stringByAppendingPathComponent:[@"WaterMarkedMovie" stringByAppendingPathExtension:@"mp4"]];
NSURL *finalVideoFileURL = [NSURL fileURLWithPath:fullMoviePath];

AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];
[exportSession setOutputFileType:AVFileTypeMPEG4];
[exportSession setOutputURL:finalVideoFileURL];
[exportSession setVideoComposition:videoComp];

[exportSession exportAsynchronouslyWithCompletionHandler:^{

    switch ([exportSession status])
    {
        case AVAssetExportSessionStatusFailed:
        {
            NSLog(@"Export Failed: %@ %@", [[exportSession error] localizedDescription], [[exportSession error] debugDescription]);

            [[NSFileManager defaultManager] removeItemAtURL:[exportSession outputURL] error:nil];

            break ;
        }
        case AVAssetExportSessionStatusCancelled:
        {
            NSLog(@"Export Cancel: %@ %@", [[exportSession error] localizedDescription], [[exportSession error] debugDescription]);

            [[NSFileManager defaultManager] removeItemAtURL:[exportSession outputURL] error:nil];

            break ;
        }
        case AVAssetExportSessionStatusCompleted:
        {
            NSLog(@"Export Complete!");

            [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {

                if (status == PHAuthorizationStatusAuthorized)
                {
                    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
                        [PHAssetChangeRequest creationRequestForAssetFromVideoAtFileURL:[exportSession outputURL]];
                    } completionHandler:^(BOOL success, NSError *error) {

                        [[NSFileManager defaultManager] removeItemAtURL:[exportSession outputURL] error:nil];

                        if (success)
                        {
                            NSLog(@"Success");
                        }
                    }];
                }
                else
                {
                    NSLog(@"Not Authorised");

                    [[NSFileManager defaultManager] removeItemAtURL:[exportSession outputURL] error:nil];
                }
            }];

            break ;
        }
        default : NSLog(@"Default") ;
    }
}];