Overlay changes color in HDR video When I’m using trying to add an overlay to an image with AVMutableVideoComposition, When the video is in HDR the overlay colors are changing and white becomes grey screen shot from original HDR video result from the code with the wrong overlay colorthe result when reducing to SDR (the right overlay color)
the distorted colorsthe way it should look(sdr)
Im creating the overlay with a CGContext
class CustomHdrCompositor: NSObject, AVVideoCompositing {
private let coreImageContext = CIContext(options: [CIContextOption.cacheIntermediates: false])
let combinedFilter = CIFilter(name: "CISourceOverCompositing")!
var sourcePixelBufferAttributes: [String: Any]? = [String(kCVPixelBufferPixelFormatTypeKey): [kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange]]
var requiredPixelBufferAttributesForRenderContext: [String: Any] =
[String(kCVPixelBufferPixelFormatTypeKey): [kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange]]
var supportsWideColorSourceFrames = true
var supportsHDRSourceFrames = true
func renderContextChanged(_ newRenderContext: AVVideoCompositionRenderContext) {
return
}
func startRequest(_ request: AVAsynchronousVideoCompositionRequest) {
guard let outputPixelBuffer = request.renderContext.newPixelBuffer() else {
print("No valid pixel buffer found. Returning.")
request.finish(with: CustomCompositorError.ciFilterFailedToProduceOutputImage)
return
}
guard let requiredTrackIDs = request.videoCompositionInstruction.requiredSourceTrackIDs, !requiredTrackIDs.isEmpty else {
print("No valid track IDs found in composition instruction.")
return
}
let sourceCount = requiredTrackIDs.count
if sourceCount > 1 {
request.finish(with: CustomCompositorError.notSupportingMoreThanOneSources)
return
}
if sourceCount == 1 {
let sourceID = requiredTrackIDs[0]
let sourceBuffer = request.sourceFrame(byTrackID: sourceID.value(of: Int32.self)!)!
let sourceCIImage = CIImage(cvPixelBuffer: sourceBuffer)
var textImage = TextLayerPlayer.instance.getTextLayerAtTimesStamp(ts:request.compositionTime.seconds)
combinedFilter.setValue(textImage, forKey: "inputImage")
if let outputImage = combinedFilter.outputImage {
let renderDestination = CIRenderDestination(pixelBuffer: outputPixelBuffer)
do {
try coreImageContext.startTask(toRender: outputImage, to: renderDestination)
} catch {
}
}
}
request.finish(withComposedVideoFrame: outputPixelBuffer)
}
}
func regularCompositionHdr(asset: AVAsset) -> AVVideoComposition
{
self.isHdr = checkHdr(asset: asset)
let avComposition = AVMutableComposition()
let composition = AVMutableVideoComposition()
composition.colorPrimaries = AVVideoColorPrimaries_ITU_R_2020
composition.colorTransferFunction = AVVideoTransferFunction_ITU_R_2100_HLG
composition.colorYCbCrMatrix = AVVideoYCbCrMatrix_ITU_R_2020
composition.renderSize = assetSize
composition.frameDuration = CMTime(value: 1, timescale: 30)
composition.customVideoCompositorClass = CustomHdrCompositor.self
composition.perFrameHDRDisplayMetadataPolicy = .propagate
return composition
}
I’m using this function to transfer the transparent CGImage to CIImage that supports HDR
func convertToHDRCIImage(from cgImage: CGImage,
maxBrightness: CGFloat = 3.0) -> CIImage? {
// Create a CIImage from the input CGImage
let baseImage = CIImage(cgImage: cgImage)
// Create HDR color adjustment filter
let colorAdjust = CIFilter(name: "CIColorMatrix")!
colorAdjust.setValue(baseImage, forKey: kCIInputImageKey)
// Calculate HDR multipliers based on maxBrightness
// This will maintain color ratios while increasing brightness
colorAdjust.setValue(CIVector(x: maxBrightness, y: 0, z: 0, w: 0), forKey: "inputRVector")
colorAdjust.setValue(CIVector(x: 0, y: maxBrightness, z: 0, w: 0), forKey: "inputGVector")
colorAdjust.setValue(CIVector(x: 0, y: 0, z: maxBrightness, w: 0), forKey: "inputBVector")
// Maintain alpha channel
colorAdjust.setValue(CIVector(x: 0, y: 0, z: 0, w: 1), forKey: "inputAVector")
guard let adjustedImage = colorAdjust.outputImage else {
return nil
}
// Apply color space transformation using CIImage's colorSpace property
let transformedImage = adjustedImage.matchedFromWorkingSpace(to: hdrWorkingSpace)!
// Create context with HDR color space
let context = CIContext(options: [
.workingColorSpace: hdrColorSpace,
.outputColorSpace: hdrColorSpace
])
// Get the image bounds
let bounds = transformedImage.extent
// Create a new pixel buffer with HDR format
var pixelBuffer: CVPixelBuffer?
let pixelBufferAttributes = [
kCVPixelBufferPixelFormatTypeKey: kCVPixelFormatType_64RGBAHalf,
kCVPixelBufferMetalCompatibilityKey: true
] as CFDictionary
CVPixelBufferCreate(kCFAllocatorDefault,
Int(bounds.width),
Int(bounds.height),
kCVPixelFormatType_64RGBAHalf,
pixelBufferAttributes,
&pixelBuffer)
guard let destinationBuffer = pixelBuffer else {
return nil
}
context.render(transformedImage,
to: destinationBuffer,
bounds: bounds,
colorSpace: hdrColorSpace)
// Create final CIImage from the HDR pixel buffer
let finalImage = CIImage(cvPixelBuffer: destinationBuffer,
options: [.colorSpace: hdrColorSpace])
return finalImage
}
When reducing the HDR to SDR it keeps the right color of the overlay with, but than it reduces the HDR effect which I want to keep
