我已经实现了类似于Apple's example的解决方案，用iPhone激光雷达摄像头捕获深度数据。主要代码片段如下：
1.设置深度格式

let device = AVCaptureDevice.default(.builtInLiDARDepthCamera, for: .video, position: .back)!
let vidFormatsWithDepth = device.formats.filter { format in
    format.formatDescription.dimensions.width == 1920 &&
    format.formatDescription.mediaSubType.rawValue == kCVPixelFormatType_420YpCbCr8BiPlanarFullRange &&
    !format.isVideoBinned &&
    !format.supportedDepthDataFormats.isEmpty &&
    format.supportedDepthDataFormats.contains { $0.formatDescription.mediaSubType.rawValue == kCVPixelFormatType_DepthFloat16 }
}

if let format = vidFormatsWithDepth.first {
    let depthFormats = format.supportedDepthDataFormats.filter { $0.formatDescription.mediaSubType.rawValue == kCVPixelFormatType_DepthFloat16 }
    try! device.lockForConfiguration()
    device.activeFormat = format
    device.activeDepthDataFormat = depthFormats.last
    device.unlockForConfiguration()
}

1.照片输出

func setUpPhotoOutput() {
    photoOutput = AVCapturePhotoOutput()
    photoOutput.maxPhotoQualityPrioritization = .quality
    self.captureSession.addOutput(photoOutput)
    photoOutput.isDepthDataDeliveryEnabled = photoOutput.isDepthDataDeliverySupported
}

1.拍摄照片

var format: [String: Any] = [:]
if photoOutput.availablePhotoPixelFormatTypes.contains(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) {
    format[kCVPixelBufferPixelFormatTypeKey as String] = kCVPixelFormatType_420YpCbCr8BiPlanarFullRange
}
let settings = AVCapturePhotoSettings(format: format)
settings.isDepthDataDeliveryEnabled = photoOutput.isDepthDataDeliveryEnabled
settings.isDepthDataFiltered = photoOutput.isDepthDataDeliveryEnabled
settings.embedsDepthDataInPhoto = photoOutput.isDepthDataDeliveryEnabled
photoOutput.capturePhoto(with: settings , delegate: self)

1.处理捕获的照片数据

func createPhotoFile(
    photo: AVCapturePhoto
) {
    let customizer = PhotoDataCustomizer()
    var mainImageData = photo.fileDataRepresentation(with: customizer)!
    // note mainImageData should have embeded depth data, but...
    let imageSource = CGImageSourceCreateWithData(mainImageData as CFData, nil)!
    let depthDataDict = CGImageSourceCopyAuxiliaryDataInfoAtIndex(
        imageSource,
        0,
        kCGImageAuxiliaryDataTypeDepth
    )
    let disparityDataDict = CGImageSourceCopyAuxiliaryDataInfoAtIndex(
        imageSource,
        0,
        kCGImageAuxiliaryDataTypeDisparity
    )
    print("depthDataDict", depthDataDict ?? "nil")
    print("disparityDataDict", disparityDataDict ?? "nil")
    // ... both depthDataDict and disparityDataDict come out as nil
}

class PhotoDataCustomizer: NSObject, AVCapturePhotoFileDataRepresentationCustomizer {
    func replacementDepthData(for photo: AVCapturePhoto) -> AVDepthData? {
        let depthData = photo.depthData?.converting(toDepthDataType: kCVPixelFormatType_DepthFloat16)
        return depthData
    }
}

AVCapturePhoto的photo.depthData是存在的（不是nil），我希望它是嵌入的，如果settings.embedsDepthDataInPhoto = true，但两个深度数据变体（kCGImageAuxiliaryDataTypeDepth，kCGImageAuxiliaryDataTypeDisparity）从CGImageSource中出来为nil。
如何正确读取照片文件中的深度数据...还是首先正确地写入深度数据？