IOS视频采集

一定要倒入 AVFoundtion #import <AVFoundation/AVFoundation.h>

AVFoundtion 框架 => 了解框架哪些类,每个类有什么用

AVCaptureDevice : 摄像头,麦克风
AVCaptureInput 输入端口
AVCaptureOutput 设备输出
AVCaptureSession 管理输入到输出数据流
AVCaptureVideoPreviewLayer : 展示采集 预览View
简单使用

//1.创建捕获会话 : 设置分辨率
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    
    //设置分辨率 720p
    session.sessionPreset = AVCaptureSessionPreset1280x720;
    
    //2. 建立输入输出轨道
    //2.1获取 设备
    //这里设备有很多的额属性可以设置 activeVideoMinFrameDuration 采样率一秒有多少帧的数据 平时10 默认60
    AVCaptureDevice *device ;
    
    for ( AVCaptureDevice *deviceNow  in [AVCaptureDevice devices])
    {
        NSLog(@"---%@", deviceNow);//[Back Camera] [Front Camera] [iPhone 麦克风]
        if (deviceNow.position == AVCaptureDevicePositionFront)
        {
            device = deviceNow;
        }
    }
    //2.2设备输入对象
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    
    //2.3将输入添加到捕获会话
    if (input != nil)
    {
        if ([session canAddInput:input])
        {
            [session addInput:input];
        }
        
    }
    
    //3.视频输出:设置视频原数据格式:YUV,RGB YUV
    //苹果不支持YUA渲染,只支持RGB渲染 -> YUV => RGB
    //3.1创建输出轨道
    AVCaptureVideoDataOutput *videoOutput = [[AVCaptureVideoDataOutput alloc] init];
    //3.2设置视频源数据格式videoSettings 设置视频原数据格式 YUV FULL
    videoOutput.videoSettings = @{(NSString *)(kCVPixelBufferPixelFormatTypeKey):@(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)};
    
    
    //3.2设置输出代理，捕获每一帧的数据
    [videoOutput setSampleBufferDelegate:self queue:dispatch_queue_create("SERIAL", DISPATCH_QUEUE_SERIAL)];
    //3.2 捕获设备，与输出设备相连接
    AVCaptureConnection *connection = [videoOutput connectionWithMediaType:AVMediaTypeVideo];
//    NSLog(@"---1%@",connection);
    //3.3给回话添加输出轨道
    if ([session canAddOutput:videoOutput])
    {
        [session addOutput:videoOutput];
    }
    
    //4.开启会话
    // 在输入与输出对象中,建立一个连接，要在添加到会话之后才可以拿到连接
    [session startRunning];
    
    connection = [videoOutput connectionWithMediaType:AVMediaTypeVideo];
    
//    NSLog(@"---2%@",connection);
    
    //设置图层预览
    AVCaptureVideoPreviewLayer *previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:session];
    
    previewLayer.frame = self.view.bounds;
    [self.view.layer addSublayer:previewLayer] ;

//代理

#pragma mark - AVCaptureVideoDataOutputSampleBufferDelegate -
- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
    NSLog(@"Image %@", sampleBuffer);
}