通过AVFoundation框架获取摄像头数据

2019-11-09 15:02:26

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一、概述从iOS4开始，AVFoundation框架增加了几个类，AVCaptureDevice、AVCapturesession等，可以获取摄像头的数据，而不会弹出类似于ImagePicker一样的界面，我们可以将数据转为一张张的图片，然后我们可以即时显示在视图上，也可以使用FFMPEG或者其它的视频编码工具，来合成视频。二、步骤第一步：创建AVCaptureSession，添加输入，输出源#import <AVFoundation/AVFoundation.h>//创建并配置一个摄像会话，并启动。- (void)setupCaptureSession{ NSError *error = nil; //创建会话 AVCaptureSession *session = [[AVCaptureSession alloc] init]; //设置视频质量 session.sessionPReset = AVCaptureSessionPresetMedium; //获取合适的AVCaptureDevice AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; //创建设备输入流，并增加到会话。 AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error]; if (!input) { //处理错误 } [session addInput:input]; //创建一个视频输出流，并增加到会话。 AVCaptureVideoDataOutput *output = [[[AVCaptureVideoDataOutput alloc] init] autorelease]; [session addOutput:output]; //配置输出流 dispatch_queue_t queue = dispatch_queue_create("myQueue", NULL); [output setSampleBufferDelegate:self queue:queue]; dispatch_release(queue); //指定像素格式。 output.videoSettings = [NSDictionary dictionaryWithObject: [NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey]; //设置FPS output.minFrameDuration = CMTimeMake(1, 15); //启动会话 [session startRunning]; //将会话与当前控制器关联 [self setSession:session];}第二步：实现AVCaptureVideoDataOutputSampleBufferDelegate协议方法 //当采样数据被写入缓冲区时调用- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{ //抽取采样数据，合成UIImage对象 UIImage *image = [self imageFromSampleBuffer:sampleBuffer]; //后续自定义处理 xxxxxxxx}//抽取采样数据，合成UIImage对象- (UIImage *)imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer{ CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); //锁定像素缓冲区的起始地址 CVPixelBufferLockBaseAddress(imageBuffer,0); //获取每行像素的字节数 size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); //获取像素缓冲区的宽度和高度 size_t width = CVPixelBufferGetWidth(imageBuffer); size_t height = CVPixelBufferGetHeight(imageBuffer); //创建基于设备的RGB颜色空间 CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); if (!colorSpace) { NSLog(@"CGColorSpaceCreateDeviceRGB failure"); return nil; } //获取像素缓冲区的起始地址 void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer); //获取像素缓冲区的数据大小 size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer); //使用提供的数据创建CGDataProviderRef CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, baseAddress, bufferSize,NULL); //通过CGDataProviderRef，创建CGImageRef CGImageRef cgImage = CGImageCreate(width, height, 8, 32, bytesPerRow, colorSpace, kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Little, provider, NULL, true, kCGRenderingIntentDefault); CGDataProviderRelease(provider); CGColorSpaceRelease(colorSpace); //创建UIImage UIImage *image = [UIImage imageWithCGImage:cgImage]; CGImageRelease(cgImage); //解锁像素缓冲区起始地址 CVPixelBufferUnlockBaseAddress(imageBuffer, 0); return image;}

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