Edit and play back HDR video with AVFoundation

6:43 - Create AVVideoComposition with custom compositor class

// Create AVVideoComposition with custom compositor class
let videoComposition = AVMutableVideoComposition()

videoComposition.instructions = [videoCompositionInstruction]
videoComposition.frameDuration = CMTimeMake(value: 1, timescale: 30)
videoComposition.renderSize = assetSize

9:55 - Create AVVideoComposition using “applyingCIFiltersWithHandler”

// Create AVVideoComposition using “applyingCIFiltersWithHandler”

let videoComposition = 
 AVMutableVideoComposition(asset: asset, 
 applyingCIFiltersWithHandler: {
     (request: AVAsynchronousCIImageFilteringRequest) -> Void in
     
     let ciFilter = CIFilter(name: “CIZoomBlur”)

     ciFilter!.setValue(request.sourceImage, forKey: kCIInputImageKey)
		 
         request.finish(with: ciFilter!.outputImage!, context: nil)
     })

10:57 - First CIKernel

// HDRHighlight.metal

#include <metal_stdlib>
#include <CoreImage/CoreImage.h>
using namespace metal;

extern “C” float4 HDRHighlight(coreimage::sample_t s, coreimage::destination dest) {       
	
    if (s.r > 1.0 || s.g > 1.0 || s.b > 1.0)
		return float4(2.0, 0.0, 0.0, 1.0);
	else
		return s;
}

11:22 - Color Inverter CI Kernel

// ColorInverter.metal - not HDR ready

#include <metal_stdlib>
#include <CoreImage/CoreImage.h>
using namespace metal;

extern “C” float4 ColorInverter(coreimage::sample_t s, coreimage::destination dest) {       
	
	return float4(1.0 - s.r, 1.0 - s.g, 1.0 - s.b, 1.0);
}

12:23 - Custom compositor class

// Custom compositor class
class SampleCustomCompositor: NSObject, AVVideoCompositing {
…
}


// Create AVVideoComposition with custom compositor class
let videoComposition = AVMutableVideoComposition()

videoComposition.instructions = [videoCompositionInstruction]
videoComposition.frameDuration = CMTimeMake(value: 1, timescale: 30)
videoComposition.renderSize = assetSize

videoComposition.customVideoCompositorClass = SampleCustomCompositor.self

13:58 - Setting custom compositor to support HDR

// Setting custom compositor to support HDR

class SampleCustomCompositor: NSObject, AVVideoCompositing {
	var sourcePixelBufferAttributes: [String : Any]? =
    [kCVPixelBufferPixelFormatTypeKey as String:
                    [kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange]]

	var requiredPixelBufferAttributesForRenderContext: [String : Any] =
			[kCVPixelBufferPixelFormatTypeKey as String: 
                            [kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange]]

	var supportsHDRSourceFrames = true
    var supportsWideColorSourceFrames = true

	func startRequest(_ request: AVAsynchronousVideoCompositionRequest) {
			 ...
	}

	func renderContextChanged(_ newRenderContext: AVVideoCompositionRenderContext) {
	}
}

21:01 - AVPlayer API definition

// API definition 
extension AVPlayer {
    @available(macOS 10.15, *)
    open class var eligibleForHDRPlayback: Bool { get }
}

21:41 - AVPlayer API definition 2

// API definition 
extension AVPlayer {
    @available(macOS 10.15, *)
    open class var eligibleForHDRPlayback: Bool { get }
}

// Set video composition color properties based on HDR playback eligibility 
if AVPlayer.eligibleForHDRPlayback {
     videoComposition.colorPrimaries = AVVideoColorPrimaries_ITU_R_2020
	 videoComposition.colorTransferFunction = AVVideoTransferFunction_ITU_R_2100_HLG
	 videoComposition.colorYCbCrMatrix = AVVideoYCbCrMatrix_ITU_R_2020
}
else {
	 videoComposition.colorPrimaries = AVVideoColorPrimaries_ITU_R_709_2
	 videoComposition.colorTransferFunction = AVVideoTransferFunction_ITU_R_709_2
	 videoComposition.colorYCbCrMatrix = AVVideoYCbCrMatrix_ITU_R_709_2
}