问题描述
我想以高帧率保存图像。 IO 很贵,不是准确的 240fps。但可能超过 120fps。
我所做的是在 viewDidLoad
中设置 capturedivece,
并在 captureOutput
中记录时间戳并查看费率。
但我注意到 captureOutput 总是 30fps。 你能告诉我我做错了什么吗?
感谢您的时间和回答!
这是我的代码和结果:
//
// ViewController.swift
// CustomCamera
//
// Created by chunibyo on 2021/3/8.
//
import UIKit
import AVFoundation
import Vision
import VideoToolBox
class ViewController: UIViewController,AVCaptureVideoDataOutputSampleBufferDelegate {
@IBOutlet weak var captureButton: UIButton!
let sessionQueue = dispatchQueue(label: "Session Queue")
var status = false
private var MyCaptureDevice: AVCaptureDevice?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
captureButton.layer.cornerRadius = captureButton.frame.width / 2
captureButton.layer.masksToBounds = true
captureButton.layer.zPosition = 10
guard let captureDevice = AVCaptureDevice.default(.builtInDualCamera,for: .video,position: .back) else {return}
guard let input = try? AVCaptureDeviceInput(device: captureDevice) else {return}
// 1
for vFormat in captureDevice.formats {
// 2
let ranges = vFormat.videoSupportedFrameRateranges as [AVFrameRaterange]
let frameRates = ranges[0]
// 3
if frameRates.maxFrameRate == 240 {
// 4
try? captureDevice.lockForConfiguration()
captureDevice.activeFormat = vFormat as AVCaptureDevice.Format
captureDevice.activeVideoMinFrameDuration = CMTimeMake(value: 1,timescale: Int32(240))
captureDevice.activeVideoMaxFrameDuration = CMTimeMake(value: 1,timescale: Int32(240))
captureDevice.videoZoomFactor = captureDevice.minAvailableVideoZoomFactor
captureDevice.unlockForConfiguration()
}
}
let captureSession = AVCaptureSession();
// captureSession.sessionPreset = .photo
captureSession.addInput(input)
captureSession.startRunning();
let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
view.layer.addSublayer(previewLayer)
previewLayer.frame = view.frame
let dataOutput = AVCaptureVideoDataOutput()
dataOutput.setSampleBufferDelegate(self,queue: dispatchQueue(label: "videoQueue"))
dataOutput.alwaysdiscardsLateVideoFrames = true;
captureSession.addOutput(dataOutput)
print(captureDevice.minAvailableVideoZoomFactor)
print(captureDevice.maxAvailableVideoZoomFactor)
MyCaptureDevice = captureDevice
}
func captureOutput(_ output: AVCaptureOutput,didOutput sampleBuffer: CMSampleBuffer,from connection: AVCaptureConnection) {
print(CMTimeGetSeconds(CMSampleBufferGetPresentationTimeStamp(sampleBuffer)))
// if !status { return }
// guard let pixelBuffer: CVPixelBuffer = CMSampleBufferGetimageBuffer(sampleBuffer) else { return }
// guard let uiImage = UIImage(pixelBuffer: pixelBuffer) else { return }
//
// sessionQueue.async {
// guard let captureDevice = self.MyCaptureDevice else { return }
// if captureDevice.videoZoomFactor >= (captureDevice.maxAvailableVideoZoomFactor - 0.2) { return }
// UIImageWritetoSavedPhotosAlbum(uiImage,nil,nil)
// try? captureDevice.lockForConfiguration()
// captureDevice.videoZoomFactor += 0.1
// captureDevice.unlockForConfiguration()
// }
}
@IBAction func captureControl(_ sender: UIButton) {
dispatchQueue.main.async {
if self.status {
self.captureButton.backgroundColor = .white
print("stop")
self.status = !self.status
}
else {
self.captureButton.backgroundColor = .red
print("recording...")
self.status = !self.status
}
}
}
}
extension UIImage {
public convenience init?(pixelBuffer: CVPixelBuffer) {
var cgImage: CGImage?
VTCreateCGImageFromCVPixelBuffer(pixelBuffer,options: nil,imageOut: &cgImage)
guard let _cgImage = cgImage else { return nil }
self.init(cgImage: _cgImage)
}
}
console log(stackoverflow 不允许我发布图片,抱歉)
解决方法
CacheConfiguration
只有日志是 240fps。
captureOutput
拍照到相册大约是 70~100fps。
此代码可以获得 240fps 的日志。
captureOutput