问题
After applying an AVVideoComposition to my AVPlayerItem, the filter I apply does work, but the video gets rotated in the AVPlayerLayer.
I know for a fact that the problem is not with the filtered frame because if I show the frame in a UIImageView, the frame is rendered 100% correctly.
The video shows correctly until I apply a videoComposition. Setting the videoGravity on the AVPlayerLayer does not help.
The video gets rotated 90º clockwise and gets stretched in the layer.
Essentially, the video is displayed perfectly in the AVPlayerLayer before the AVPlayerItem is fed through the AVMutableVideoComposition. Once that happens, the video is rotated -90º, and then scaled to fit the same dimensions as the video before filtering. This suggests to me that it does not realize that its transform is already correct, and so it is reapplying the transform on itself.
Why is this happening, and how can I fix it?
Here is some code:
private func filterVideo(with filter: Filter?) {
if let player = player, let playerItem = player.currentItem {
let composition = AVMutableComposition()
let videoAssetTrack = playerItem.asset.tracks(withMediaType: .video).first
let videoCompositionTrack = composition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
try? videoCompositionTrack?.insertTimeRange(CMTimeRange(start: kCMTimeZero, duration: playerItem.asset.duration), of: videoAssetTrack!, at: kCMTimeZero)
videoCompositionTrack?.preferredTransform = videoAssetTrack!.preferredTransform
let videoComposition = AVMutableVideoComposition(asset: composition, applyingCIFiltersWithHandler: { (request) in
let filteredImage = <...>
request.finish(with: filteredImage, context: nil)
})
playerItem.videoComposition = videoComposition
}
}
回答1:
You have a problem in the renderingSize of AVVideoComposition. You should apply transform on AVMutableVideoCompositionInstruction (ie. Rotate and translate transform ).
I have done it in Objective-c and am posting my code. You can convert the syntax into Swift
Objective-c
//------------------------------------
// FIXING ORIENTATION
//------------------------------------
AVMutableVideoCompositionInstruction * MainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
MainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeAdd(firstAsset.duration, secondAsset.duration));
AVMutableVideoCompositionLayerInstruction *FirstlayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:secondTrack]; // second
AVAssetTrack *FirstAssetTrack = [[firstAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
UIImageOrientation FirstAssetOrientation_ = UIImageOrientationUp;
BOOL isFirstAssetPortrait_ = NO;
CGAffineTransform firstTransform = FirstAssetTrack.preferredTransform;
if(firstTransform.a == 0 && firstTransform.b == 1.0 && firstTransform.c == -1.0 && firstTransform.d == 0) {FirstAssetOrientation_= UIImageOrientationRight; isFirstAssetPortrait_ = YES;}
if(firstTransform.a == 0 && firstTransform.b == -1.0 && firstTransform.c == 1.0 && firstTransform.d == 0) {FirstAssetOrientation_ = UIImageOrientationLeft; isFirstAssetPortrait_ = YES;}
if(firstTransform.a == 1.0 && firstTransform.b == 0 && firstTransform.c == 0 && firstTransform.d == 1.0) {FirstAssetOrientation_ = UIImageOrientationUp;}
if(firstTransform.a == -1.0 && firstTransform.b == 0 && firstTransform.c == 0 && firstTransform.d == -1.0) {FirstAssetOrientation_ = UIImageOrientationDown;}
CGFloat FirstAssetScaleToFitRatio = 320.0/FirstAssetTrack.naturalSize.width;
if(isFirstAssetPortrait_){
FirstAssetScaleToFitRatio = 320.0/FirstAssetTrack.naturalSize.height;
CGAffineTransform FirstAssetScaleFactor = CGAffineTransformMakeScale(FirstAssetScaleToFitRatio,FirstAssetScaleToFitRatio);
[FirstlayerInstruction setTransform:CGAffineTransformConcat(FirstAssetTrack.preferredTransform, FirstAssetScaleFactor) atTime:kCMTimeZero];
}else{
CGAffineTransform FirstAssetScaleFactor = CGAffineTransformMakeScale(FirstAssetScaleToFitRatio,FirstAssetScaleToFitRatio);
[FirstlayerInstruction setTransform:CGAffineTransformConcat(CGAffineTransformConcat(FirstAssetTrack.preferredTransform, FirstAssetScaleFactor),CGAffineTransformMakeTranslation(0, 160)) atTime:kCMTimeZero];
}
[FirstlayerInstruction setOpacity:0.0 atTime:firstAsset.duration];
AVMutableVideoCompositionLayerInstruction *SecondlayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:firstTrack];
AVAssetTrack *SecondAssetTrack = [[secondAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
UIImageOrientation SecondAssetOrientation_ = UIImageOrientationUp;
BOOL isSecondAssetPortrait_ = NO;
CGAffineTransform secondTransform = SecondAssetTrack.preferredTransform;
if(secondTransform.a == 0 && secondTransform.b == 1.0 && secondTransform.c == -1.0 && secondTransform.d == 0) {SecondAssetOrientation_= UIImageOrientationRight; isSecondAssetPortrait_ = YES;}
if(secondTransform.a == 0 && secondTransform.b == -1.0 && secondTransform.c == 1.0 && secondTransform.d == 0) {SecondAssetOrientation_ = UIImageOrientationLeft; isSecondAssetPortrait_ = YES;}
if(secondTransform.a == 1.0 && secondTransform.b == 0 && secondTransform.c == 0 && secondTransform.d == 1.0) {SecondAssetOrientation_ = UIImageOrientationUp;}
if(secondTransform.a == -1.0 && secondTransform.b == 0 && secondTransform.c == 0 && secondTransform.d == -1.0) {SecondAssetOrientation_ = UIImageOrientationDown;}
CGFloat SecondAssetScaleToFitRatio = 320.0/SecondAssetTrack.naturalSize.width;
if(isSecondAssetPortrait_){
SecondAssetScaleToFitRatio = 320.0/SecondAssetTrack.naturalSize.height;
CGAffineTransform SecondAssetScaleFactor = CGAffineTransformMakeScale(SecondAssetScaleToFitRatio,SecondAssetScaleToFitRatio);
[SecondlayerInstruction setTransform:CGAffineTransformConcat(SecondAssetTrack.preferredTransform, SecondAssetScaleFactor) atTime:firstAsset.duration];
}else{
;
CGAffineTransform SecondAssetScaleFactor = CGAffineTransformMakeScale(SecondAssetScaleToFitRatio,SecondAssetScaleToFitRatio);
[SecondlayerInstruction setTransform:CGAffineTransformConcat(CGAffineTransformConcat(SecondAssetTrack.preferredTransform, SecondAssetScaleFactor),CGAffineTransformMakeTranslation(0, 160)) atTime:secondAsset.duration];
}
MainInstruction.layerInstructions = [NSArray arrayWithObjects:SecondlayerInstruction,nil];;
AVMutableVideoComposition *MainCompositionInst = [AVMutableVideoComposition videoComposition];
MainCompositionInst.instructions = [NSArray arrayWithObject:MainInstruction];
MainCompositionInst.frameDuration = CMTimeMake(1, 30);
MainCompositionInst.renderSize = CGSizeMake(320.0, 480.0);
// Now , you have Orientation Fixed Instrucation layer
// add this composition to your video 😀
// If you want to export Video than you can do like below
NSString *documentsDirectory = [NSHomeDirectory()
stringByAppendingPathComponent:@"Documents"];
NSString *myPathDocs = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"final_merged_video-%d.mp4",arc4random() % 1000]];
NSURL *url = [NSURL fileURLWithPath:myPathDocs];
// 5 - Create exporter
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition
presetName:AVAssetExportPreset640x480];
exporter.outputURL=url;
exporter.videoComposition=MainCompositionInst;
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = YES;
[exporter exportAsynchronouslyWithCompletionHandler:^{
dispatch_async(dispatch_get_main_queue(), ^
{
[[AppDelegate Getdelegate] hideIndicator];
[self exportDidFinish:exporter];
});
}];
for Swift see this answer Click here
in addition you can also try to rotate your video layer by applying rotation transform on it.
#define degreeToRadian(x) (M_PI * x / 180.0)
[_playerLayer setAffineTransform:CGAffineTransformMakeRotation(degreeToRadian(degree))]
回答2:
If You are trying to play AVMutableCompostion You should set AVAssetTrack's preferredTransform to AVMutableCompositionTrack's preferredTransform.
let asset = AVAsset(url: url!)
let composition = AVMutableComposition()
let compositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid)
let videoTrack = asset.tracks(withMediaType: AVMediaTypeVideo).first
try? compositionTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, asset.duration), of: videoTrack!, at: kCMTimeZero)
compositionTrack.preferredTransform = (videoTrack?.preferredTransform)!
let playerItem = AVPlayerItem(asset: composition)
let filter = CIFilter(name: "CIColorInvert")
playerItem.videoComposition = AVVideoComposition(asset: composition, applyingCIFiltersWithHandler: { (request: AVAsynchronousCIImageFilteringRequest) in
filter?.setValue(request.sourceImage, forKey: kCIInputImageKey)
request.finish(with: (filter?.outputImage)!, context: nil)
})
.... the rest of code
回答3:
Instead of assuming that the image will be filtered, check first if filteredImage is nil. If not, then request.finish(with: filteredImage, context: nil)
However, if it is nil you must request.finish(with: SomeError)
This is as per the docs.
回答4:
What worked for me at the end:
private func filterVideo(with filter: Filter?) {
guard let player = playerLayer?.player, let playerItem = player.currentItem else { return }
let videoComposition = AVVideoComposition(asset: playerItem.asset, applyingCIFiltersWithHandler: { (request) in
if let filter = filter {
if let filteredImage = filter.filterImage(request.sourceImage) {
let output = filteredImage.cropping(to: request.sourceImage.extent)
request.finish(with: output, context: nil)
} else {
printError("Image not filtered")
request.finish(with: RenderError.couldNotFilter)
}
} else {
let output = request.sourceImage.cropping(to: request.sourceImage.extent)
request.finish(with: output, context: nil)
}
})
playerItem.videoComposition = videoComposition
}
This is the filterImage function of Filter, which is just a nice little wrapper for CIFilter:
func filterImage(_ ciImage: CIImage) -> CIImage? {
guard let filter = ciFilter else { return nil }
filter.setDefaults()
filter.setValue(ciImage, forKey: kCIInputImageKey)
guard let filteredImageData = filter.value(forKey: kCIOutputImageKey) as? CIImage else { return nil }
return filteredImageData
}
回答5:
Try this code below which worked for me
// Grab the source track from AVURLAsset for example.
let assetV = YourAVASSET.tracks(withMediaType: AVMediaTypeVideo).last
// Grab the composition video track from AVMutableComposition you already made.
let compositionV = YourCompostion.tracks(withMediaType: AVMediaTypeVideo).last
// Apply the original transform.
if ((assetV != nil) && (compostionV != nil)) {
compostionV?.preferredTransform = (assetV?.preferredTransform)!
}
And then go ahead an export your video...
来源：https://stackoverflow.com/questions/44911802/video-rotated-after-applying-avvideocomposition