An object that supprts using Core Image filters to process an individual video frame in a video composition.
SDKs
- iOS 9.0+
- macOS 10.11+
- Mac Catalyst 13.0+
- tvOS 9.0+
Framework
- AVFoundation
Declaration
@interface AVAsynchronousCIImageFilteringRequest : NSObject
Overview
You use this class when creating a composition for Core Image filtering with the video method. In that method call, you provide a block to be called by AVFoundation as it processes each frame of video, and the block’s sole parameter is a AVAsynchronous object. Use that object both to the video frame image to be filtered and allows you to return a filtered image to AVFoundation for display or export. Listing 1 shows an example of applying a filter to an asset.
Applying Core Image filters to a video asset
CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];
AVVideoComposition *composition = [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];
// Vary filter parameters based on video timing
Float64 seconds = CMTimeGetSeconds(request.compositionTime);
[filter setValue:seconds * 10.0 forKey:kCIInputRadiusKey];
// 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];
}];