让你的 iOS App 支持 Center Stage 前置摄像头

5:29 - Support dynamic aspect ratio

// Select the Center Stage front camera

import AVFoundation

let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInUltraWideCamera], mediaType: .video, position: .front)

guard let camera = deviceDiscoverySession.devices.first else {
    print("Failed to find the capture device")
    return
}

// Find a format that supports the 4x3 aspect ratio

for format in camera.formats {
    if format.supportedDynamicAspectRatios.contains(.ratio4x3) {
        try! camera.lockForConfiguration()
        camera.activeFormat = format
        camera.unlockForConfiguration()
        break
    }
}

// Set dynamic aspect ratio

try! camera.lockForConfiguration()

let timestamp = try! await camera.setDynamicAspectRatio(.ratio4x3)
print("Applied dynamic aspect ratio at timestamp: \(timestamp)")

camera.unlockForConfiguration()

7:39 - Support smart framing monitor

// Find a format that supports smart framing

import AVFoundation

for format in camera.formats {
    if format.isSmartFramingSupported {
        try! camera.lockForConfiguration()
        camera.activeFormat = format
        camera.unlockForConfiguration()
        break
    }
}

// Configure the smart framing monitor

let monitor = camera.smartFramingMonitor!

try! camera.lockForConfiguration()
monitor.enabledFramings = monitor.supportedFramings
camera.unlockForConfiguration()

// Monitor framing recommendations

observation = monitor.observe(\.recommendedFraming, options: [.new,]) { monitor, change in
    if let framing = monitor.recommendedFraming {

        Task {
            try! camera.lockForConfiguration()
            try! await camera.setDynamicAspectRatio(framing.aspectRatio)
            camera.videoZoomFactor = CGFloat(framing.zoomFactor)
            camera.unlockForConfiguration()
        }

    }
}

// Start the smart framing monitor

try! monitor.startMonitoring()

// Stop the smart framing monitor

observation?.invalidate()
observation = nil

monitor.stopMonitoring()

14:44 - Support Center Stage for video calls

// Find a format that supports Center Stage

import AVFoundation

for format in camera.formats {
    if format.isCenterStageSupported {
        try! camera.lockForConfiguration()
        camera.activeFormat = format
        camera.unlockForConfiguration()
        break
    }
}

// Turn on Center Stage

AVCaptureDevice.centerStageControlMode = .cooperative
AVCaptureDevice.isCenterStageEnabled = true