objective-c - 未在视频上正确应用 CIFilter

Question

我有 2 个肖像视频。一张是从默认 iPhone 摄像头拍摄的，第二张是使用 UIIMagePickerController 从我的应用程序中记录的。

当我在视频 1 上应用 cifilter 时，过滤器应用完美，但当我在第二个视频上应用过滤器时，视频会缩放，一半视频部分模糊和拉伸(stretch)，当我导出它时，它应该旋转。

我的代码

AVAssetTrack *FirstAssetTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

CIFilter *filter = [CIFilter filterWithName:@"CIPhotoEffectInstant"];

player.currentItem.videoComposition  = [AVVideoComposition videoCompositionWithAsset: asset applyingCIFiltersWithHandler:^(AVAsynchronousCIImageFilteringRequest *request){
    // Clamp to avoid blurring transparent pixels at the image edges

    CIImage *source = [request.sourceImage imageByClampingToExtent];
    source = [source imageByApplyingTransform:FirstAssetTrack.preferredTransform];

    [filter setValue:source forKey:kCIInputImageKey];

    // Crop the blurred output to the bounds of the original image
    CIImage *output = [filter.outputImage imageByCroppingToRect:request.sourceImage.extent];

    // Provide the filter output to the composition
    [request finishWithImage:output context:nil];
}];

此代码不适用于第二个视频，因此第二个视频需要进行一些更改 这不是正确的代码，但我想检查它的大小和方向，方向改变后，在 avplayer 中播放时它工作正常，但导出时它会旋转

AVPlayer plays video composition result incorrectly

我检查了这个链接，我们都面临着同样的问题，所以我根据这个更改了我的代码，但仍然无法正常工作

AVAssetTrack *FirstAssetTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
CIFilter *filter = [CIFilter filterWithName:@"CIPhotoEffectInstant"];


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;
}

player.currentItem.videoComposition = [AVVideoComposition videoCompositionWithAsset:asset applyingCIFiltersWithHandler:^(AVAsynchronousCIImageFilteringRequest * _Nonnull request) {
    // Step 1: get the input frame image (screenshot 1)
    CIImage *sourceImage = request.sourceImage;

    // Step 2: rotate the frame
    CIFilter *transformFilter = [CIFilter filterWithName:@"CIAffineTransform"];
    [transformFilter setValue:sourceImage forKey: kCIInputImageKey];
    [transformFilter setValue: [NSValue valueWithCGAffineTransform: firstTransform] forKey: kCIInputTransformKey];
    sourceImage = transformFilter.outputImage;
    CGRect extent = sourceImage.extent;
    CGAffineTransform translation = CGAffineTransformMakeTranslation(-extent.origin.x, -extent.origin.y);
    [transformFilter setValue:sourceImage forKey: kCIInputImageKey];
    [transformFilter setValue: [NSValue valueWithCGAffineTransform: translation] forKey: kCIInputTransformKey];
    sourceImage = transformFilter.outputImage;

    // Step 3: apply the custom filter chosen by the user
    extent = sourceImage.extent;
    sourceImage = [sourceImage imageByClampingToExtent];
    [filter setValue:sourceImage forKey:kCIInputImageKey];
    sourceImage = filter.outputImage;
    sourceImage = [sourceImage imageByCroppingToRect:extent];

    // make the frame the same aspect ratio as the original input frame
    // by adding empty spaces at the top and the bottom of the extent rectangle
    CGFloat newHeight = 1920 * 1920 / extent.size.height;
    CGFloat inset = (extent.size.height - newHeight) / 2;
    extent = CGRectInset(extent, 0, inset);
    sourceImage = [sourceImage imageByCroppingToRect:extent];

    // scale down to the original frame size
    CGFloat scale = 1920 / newHeight;
    CGAffineTransform scaleTransform = CGAffineTransformMakeScale(scale, scale*3.2);
    [transformFilter setValue:sourceImage forKey: kCIInputImageKey];
    [transformFilter setValue: [NSValue valueWithCGAffineTransform: scaleTransform] forKey: kCIInputTransformKey];
    sourceImage = transformFilter.outputImage;

    // translate the frame to make it's origin start at (0, 0)
    CGAffineTransform translation1 = CGAffineTransformMake(1, 0, 0, 1, 0, 0);
    [transformFilter setValue:sourceImage forKey: kCIInputImageKey];
    [transformFilter setValue: [NSValue valueWithCGAffineTransform: translation1] forKey: kCIInputTransformKey];
    sourceImage = transformFilter.outputImage;

    // Step 4: finish processing the frame (screenshot 2)
    [request finishWithImage:sourceImage context:nil];

}];

Answer 1

只需删除你的变换线，这会导致问题。

只有这个:

source = [source imageByApplyingTransform:FirstAssetTrack.preferredTransform];

并检查。 :)

AVAssetTrack *FirstAssetTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

CIFilter *filter = [CIFilter filterWithName:@"CIPhotoEffectInstant"];

player.currentItem.videoComposition  = [AVVideoComposition videoCompositionWithAsset: asset applyingCIFiltersWithHandler:^(AVAsynchronousCIImageFilteringRequest *request){
    // Clamp to avoid blurring transparent pixels at the image edges

    CIImage *source = [request.sourceImage imageByClampingToExtent];

    [filter setValue:source forKey:kCIInputImageKey];

    // Crop the blurred output to the bounds of the original image
    CIImage *output = [filter.outputImage imageByCroppingToRect:request.sourceImage.extent];

    // Provide the filter output to the composition
    [request finishWithImage:output context:nil];
}];