这与将CMSampleBuffer转换为UIImage的无数问题不同。我只是想知道为什么我不能这样转换它：
CVPixelBufferRef pixelBuffer = (CVPixelBufferRef)CMSampleBufferGetImageBuffer(sampleBuffer);
CIImage * imageFromCoreImageLibrary = [CIImage imageWithCVPixelBuffer: pixelBuffer];
UIImage * imageForUI = [UIImage imageWithCIImage: imageFromCoreImageLibrary];
它似乎更简单，因为它适用于YCbCr色彩空间，以及RGBA等。该代码有问题吗？
答案 0 :(得分：22)
对于JPEG图像：
Swift 4：
let buff: CMSampleBuffer ... // Have you have CMSampleBuffer
if let imageData = AVCapturePhotoOutput.jpegPhotoDataRepresentation(forJPEGSampleBuffer: buff, previewPhotoSampleBuffer: nil) {
let image = UIImage(data: imageData) // Here you have UIImage
}
答案 1 :(得分：20)
使用Swift 3和iOS 10 AVCapturePhotoOutput： 包括：
import UIKit
import CoreData
import CoreMotion
import AVFoundation
创建一个UIView进行预览并将其链接到Main Class
@IBOutlet var preview: UIView!
创建此项以设置相机会话（ kCVPixelFormatType_32BGRA 非常重要!!）：
lazy var cameraSession: AVCaptureSession = {
let s = AVCaptureSession()
s.sessionPreset = AVCaptureSessionPresetHigh
return s
}()
lazy var previewLayer: AVCaptureVideoPreviewLayer = {
let previewl:AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: self.cameraSession)
previewl.frame = self.preview.bounds
return previewl
}()
func setupCameraSession() {
let captureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo) as AVCaptureDevice
do {
let deviceInput = try AVCaptureDeviceInput(device: captureDevice)
cameraSession.beginConfiguration()
if (cameraSession.canAddInput(deviceInput) == true) {
cameraSession.addInput(deviceInput)
}
let dataOutput = AVCaptureVideoDataOutput()
dataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString) : NSNumber(value: **kCVPixelFormatType_32BGRA** as UInt32)]
dataOutput.alwaysDiscardsLateVideoFrames = true
if (cameraSession.canAddOutput(dataOutput) == true) {
cameraSession.addOutput(dataOutput)
}
cameraSession.commitConfiguration()
let queue = DispatchQueue(label: "fr.popigny.videoQueue", attributes: [])
dataOutput.setSampleBufferDelegate(self, queue: queue)
}
catch let error as NSError {
NSLog("\(error), \(error.localizedDescription)")
}
}
WillAppear：
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
setupCameraSession()
}
在Didappear：
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
preview.layer.addSublayer(previewLayer)
cameraSession.startRunning()
}
创建一个捕获输出的函数：
func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
// Here you collect each frame and process it
let ts:CMTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer)
self.mycapturedimage = imageFromSampleBuffer(sampleBuffer: sampleBuffer)
}
以下是将 kCVPixelFormatType_32BGRA CMSampleBuffer转换为 UIImage 的代码，关键字是 bitmapInfo ，必须与 32BGRA对应 32与preultfirst和alpha信息很少：
func imageFromSampleBuffer(sampleBuffer : CMSampleBuffer) -> UIImage
{
// Get a CMSampleBuffer's Core Video image buffer for the media data
let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
// Lock the base address of the pixel buffer
CVPixelBufferLockBaseAddress(imageBuffer!, CVPixelBufferLockFlags.readOnly);
// Get the number of bytes per row for the pixel buffer
let baseAddress = CVPixelBufferGetBaseAddress(imageBuffer!);
// Get the number of bytes per row for the pixel buffer
let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer!);
// Get the pixel buffer width and height
let width = CVPixelBufferGetWidth(imageBuffer!);
let height = CVPixelBufferGetHeight(imageBuffer!);
// Create a device-dependent RGB color space
let colorSpace = CGColorSpaceCreateDeviceRGB();
// Create a bitmap graphics context with the sample buffer data
var bitmapInfo: UInt32 = CGBitmapInfo.byteOrder32Little.rawValue
bitmapInfo |= CGImageAlphaInfo.premultipliedFirst.rawValue & CGBitmapInfo.alphaInfoMask.rawValue
//let bitmapInfo: UInt32 = CGBitmapInfo.alphaInfoMask.rawValue
let context = CGContext.init(data: baseAddress, width: width, height: height, bitsPerComponent: 8, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo)
// Create a Quartz image from the pixel data in the bitmap graphics context
let quartzImage = context?.makeImage();
// Unlock the pixel buffer
CVPixelBufferUnlockBaseAddress(imageBuffer!, CVPixelBufferLockFlags.readOnly);
// Create an image object from the Quartz image
let image = UIImage.init(cgImage: quartzImage!);
return (image);
}
答案 2 :(得分：13)
使用以下代码从PixelBuffer转换图像 选项1：
CIImage *ciImage = [CIImage imageWithCVPixelBuffer:pixelBuffer];
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef myImage = [context
createCGImage:ciImage
fromRect:CGRectMake(0, 0,
CVPixelBufferGetWidth(pixelBuffer),
CVPixelBufferGetHeight(pixelBuffer))];
UIImage *uiImage = [UIImage imageWithCGImage:myImage];
选项2：
int w = CVPixelBufferGetWidth(pixelBuffer);
int h = CVPixelBufferGetHeight(pixelBuffer);
int r = CVPixelBufferGetBytesPerRow(pixelBuffer);
int bytesPerPixel = r/w;
unsigned char *buffer = CVPixelBufferGetBaseAddress(pixelBuffer);
UIGraphicsBeginImageContext(CGSizeMake(w, h));
CGContextRef c = UIGraphicsGetCurrentContext();
unsigned char* data = CGBitmapContextGetData(c);
if (data != NULL) {
int maxY = h;
for(int y = 0; y<maxY; y++) {
for(int x = 0; x<w; x++) {
int offset = bytesPerPixel*((w*y)+x);
data[offset] = buffer[offset]; // R
data[offset+1] = buffer[offset+1]; // G
data[offset+2] = buffer[offset+2]; // B
data[offset+3] = buffer[offset+3]; // A
}
}
}
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
答案 3 :(得分：7)
我写了一个简单的扩展名，用于 Swift 4.x / 3.x ，以便从UIImage生成CMSampleBuffer。
这也可以处理缩放和方向，但如果它们适合你，你可以接受默认值。
import UIKit
import AVFoundation
extension CMSampleBuffer {
func image(orientation: UIImageOrientation = .up,
scale: CGFloat = 1.0) -> UIImage? {
if let buffer = CMSampleBufferGetImageBuffer(self) {
let ciImage = CIImage(cvPixelBuffer: buffer)
return UIImage(ciImage: ciImage,
scale: scale,
orientation: orientation)
}
return nil
}
}
CIImage UIImage初始化的ciImage值，以及scale＆amp; orientation值。如果未提供，则分别使用up和1.0的默认值答案 4 :(得分：2)
这将与iOS 10 AVCapturePhotoOutput类有关。假设用户想要拍照并且您拨打capturePhoto(with:delegate:)并且您的设置包含对预览图像的请求。这是获得预览图像的绝佳方式，但是如何在界面中显示它？预览图像在委托方法的实现中作为CMSampleBuffer到达：
func capture(_ output: AVCapturePhotoOutput,
didFinishProcessingPhotoSampleBuffer buff: CMSampleBuffer?,
previewPhotoSampleBuffer: CMSampleBuffer?,
resolvedSettings: AVCaptureResolvedPhotoSettings,
bracketSettings: AVCaptureBracketedStillImageSettings?,
error: Error?) {
您需要将CMSampleBuffer previewPhotoSampleBuffer转换为UIImage。你打算怎么做？像这样：
if let prev = previewPhotoSampleBuffer {
if let buff = CMSampleBufferGetImageBuffer(prev) {
let cim = CIImage(cvPixelBuffer: buff)
let im = UIImage(ciImage: cim)
// and now you have a UIImage! do something with it ...
}
}
答案 5 :(得分：1)
全部：请勿使用以下方法：
private let context = CIContext()
private func imageFromSampleBuffer2(_ sampleBuffer: CMSampleBuffer) -> UIImage? {
guard let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else { return nil }
let ciImage = CIImage(cvPixelBuffer: imageBuffer)
guard let cgImage = context.createCGImage(ciImage, from: ciImage.extent) else { return nil }
return UIImage(cgImage: cgImage)
}
他们吃了更多的cpu，转换的时间更多
使用https://stackoverflow.com/a/40193359/7767664
中的解决方案不要忘记为AVCaptureVideoDataOutput
设置下一个设置 videoOutput = AVCaptureVideoDataOutput()
videoOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as String) : NSNumber(value: kCVPixelFormatType_32BGRA as UInt32)]
//videoOutput.alwaysDiscardsLateVideoFrames = true
videoOutput.setSampleBufferDelegate(self, queue: DispatchQueue(label: "MyQueue"))
转换方法
func imageFromSampleBuffer(_ sampleBuffer : CMSampleBuffer) -> UIImage {
// Get a CMSampleBuffer's Core Video image buffer for the media data
let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
// Lock the base address of the pixel buffer
CVPixelBufferLockBaseAddress(imageBuffer!, CVPixelBufferLockFlags.readOnly);
// Get the number of bytes per row for the pixel buffer
let baseAddress = CVPixelBufferGetBaseAddress(imageBuffer!);
// Get the number of bytes per row for the pixel buffer
let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer!);
// Get the pixel buffer width and height
let width = CVPixelBufferGetWidth(imageBuffer!);
let height = CVPixelBufferGetHeight(imageBuffer!);
// Create a device-dependent RGB color space
let colorSpace = CGColorSpaceCreateDeviceRGB();
// Create a bitmap graphics context with the sample buffer data
var bitmapInfo: UInt32 = CGBitmapInfo.byteOrder32Little.rawValue
bitmapInfo |= CGImageAlphaInfo.premultipliedFirst.rawValue & CGBitmapInfo.alphaInfoMask.rawValue
//let bitmapInfo: UInt32 = CGBitmapInfo.alphaInfoMask.rawValue
let context = CGContext.init(data: baseAddress, width: width, height: height, bitsPerComponent: 8, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo)
// Create a Quartz image from the pixel data in the bitmap graphics context
let quartzImage = context?.makeImage();
// Unlock the pixel buffer
CVPixelBufferUnlockBaseAddress(imageBuffer!, CVPixelBufferLockFlags.readOnly);
// Create an image object from the Quartz image
let image = UIImage.init(cgImage: quartzImage!);
return (image);
}
答案 6 :(得分：1)
Swift 5.0
if let cvImageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) {
let ciimage = CIImage(cvImageBuffer: cvImageBuffer)
let context = CIContext()
if let cgImage = context.createCGImage(ciimage, from: ciimage.extent) {
let uiImage = UIImage(cgImage: cgImage)
}
}
答案 7 :(得分：-1)
Swift 4 / iOS 11版本的Popigny回答：
content_type在上下文中查看此内容的完整示例项目：https://github.com/cruinh/CameraCapture