在标题中,我试图从方法的输出中检索捕获的照片的CVPixelBuffer:
AVCapturePhotoCaptureDelegate.photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?)
委托方法调用中的photo
参数pixelBuffer
为nil
,我希望将其用于某些低级图像操作。
我主要关注的示例代码可以在以下网址找到:
https://developer.apple.com/library/content/samplecode/AVCam/Introduction/Intro.html
和AVFoundation文档。
由于AVFoundation会话配置有点冗长并且可能提供一些答案,我只是粘贴处理它的整个对象,它应包含所有相关代码:
protocol CameraServiceDelegate: class {
func cameraServiceDidCapturePhoto(withBuffer buffer: CVPixelBuffer)
func cameraServiceEncounteredError(_ error: Error?)
}
final class CameraService: NSObject {
struct BufferRetrievalFailure: Error {}
weak var delegate: CameraServiceDelegate?
private let session = AVCaptureSession()
private var discoverySession = AVCaptureDevice.DiscoverySession(
deviceTypes: [.builtInDualCamera, .builtInWideAngleCamera],
mediaType: .video,
position: .back
)
private var deviceInput: AVCaptureDeviceInput!
private let photoOutput = AVCapturePhotoOutput()
private let sessionQueue = DispatchQueue(label: "av-capture-session.serial.queue")
private var captureDevice: AVCaptureDevice? {
return .default(.builtInDualCamera, for: .video, position: .back)
?? .default(.builtInWideAngleCamera, for: .video, position: .back)
?? .default(.builtInWideAngleCamera, for: .video, position: .front)
}
func setup(with layer: AVCaptureVideoPreviewLayer) {
layer.session = session
switch AVCaptureDevice.authorizationStatus(for: .video) {
case .authorized:
break
case .notDetermined:
requestVideoAuthorization()
default:
assertionFailure("Just enable video, this is not a real app.")
}
sessionQueue.async { [weak self] in
self?.setupAVSession(with: layer)
}
}
func resume() {
sessionQueue.async { [weak session] in
session?.startRunning()
}
}
func suspend() {
sessionQueue.async { [weak session] in
session?.stopRunning()
}
}
func capturePhoto() {
sessionQueue.async { [weak self] in
guard let strongSelf = self else {
return
}
strongSelf.photoOutput.capturePhoto(with: strongSelf.capturePhotoSettings(), delegate: strongSelf)
}
}
private func requestVideoAuthorization() {
sessionQueue.suspend()
AVCaptureDevice.requestAccess(for: .video) { [weak sessionQueue] isAuthorized in
guard isAuthorized else {
assertionFailure("Just enable video, this is not a real app.")
return
}
sessionQueue?.resume()
}
}
private func setupAVSession(with layer: AVCaptureVideoPreviewLayer) {
session.beginConfiguration()
session.sessionPreset = .photo
setupVideoInput()
setupVideoPreviewViewLayer(with: layer)
setupPhotoOutput()
session.commitConfiguration()
}
private func setupVideoInput() {
guard let videoDevice = captureDevice,
let deviceInput = try? AVCaptureDeviceInput(device: videoDevice),
session.canAddInput(deviceInput) else {
fatalError("Could not retrieve suitable capture device or configure video device input.")
}
self.deviceInput = deviceInput
session.addInput(deviceInput)
}
private func setupVideoPreviewViewLayer(with layer: AVCaptureVideoPreviewLayer) {
DispatchQueue.main.async {
let statusBarOrientation = UIApplication.shared.statusBarOrientation
layer.connection?.videoOrientation =
statusBarOrientation != .unknown
? AVCaptureVideoOrientation(rawValue: statusBarOrientation.rawValue)!
: .portrait
}
}
private func setupPhotoOutput() {
guard session.canAddOutput(photoOutput) else {
fatalError("Could not configure photo output.")
}
session.addOutput(photoOutput)
photoOutput.isHighResolutionCaptureEnabled = true
photoOutput.isLivePhotoCaptureEnabled = false
photoOutput.isDepthDataDeliveryEnabled = photoOutput.isDepthDataDeliverySupported
}
private func capturePhotoSettings() -> AVCapturePhotoSettings {
let settings: AVCapturePhotoSettings
if photoOutput.availablePhotoCodecTypes.contains(.hevc) {
settings = AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.hevc])
} else {
settings = AVCapturePhotoSettings()
}
settings.isHighResolutionPhotoEnabled = true
settings.isDepthDataDeliveryEnabled = photoOutput.isDepthDataDeliveryEnabled
return settings
}
}
extension CameraService: AVCapturePhotoCaptureDelegate {
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
guard error == nil else {
delegate?.cameraServiceEncounteredError(error)
return
}
guard let buffer = photo.pixelBuffer else {
delegate?.cameraServiceEncounteredError(BufferRetrievalFailure())
return
}
delegate?.cameraServiceDidCapturePhoto(withBuffer: buffer)
}
}
答案 0 :(得分:1)
我没有代码示例,因为我正在Xamarin中工作,但是您需要在创建捕获时在使用的AVCapturePhotoSettings
对象上设置previewPhotoFormat
。我的一个例子found online:
var settings = AVCapturePhotoSettings()
let previewPixelType = settings.availablePreviewPhotoPixelFormatTypes.first!
let previewFormat = [
kCVPixelBufferPixelFormatTypeKey as String: previewPixelType,
kCVPixelBufferWidthKey as String: self.capturedButton.frame.width,
kCVPixelBufferHeightKey as String: self.capturedButton.frame.height
] as [String : Any]
settings.previewPhotoFormat = previewFormat
我个人检查availablePreviewPhotoPixelFormatTypes
,以查看分析所需的格式(kCVPixelFormatType_32BGRA
)是否均匀存在。到目前为止,我还没有遇到没有它的设备。