零基础学习iOS直播之采集

// 采集- (void)setupCaputureVideo { // 1.创建捕获对话，必须要强引用，否则会释放 _captureSession = [[AVCaptureSession alloc] init]; // 2.捕获摄像头设备，默认前置摄像头 AVCaptureDevice *videoDevice = [self getVideoDevice:AVCaptureDevicePositionFront]; // 3.获取声音设备 AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio]; // 4.创建对应视频设备输入对象 _currentVideoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil]; // 5.创建对应音频设备输入对象 AVCaptureDeviceInput *audioDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:nil]; // 6.添加到会话中 注意：最好要判断是否能添加输入，会话不能添加空的 // 6.1 添加视频 if ([_captureSession canAddInput:_currentVideoDeviceInput]) { [_captureSession addInput:_currentVideoDeviceInput]; } // 6.2 添加音频 if ([_captureSession canAddInput:audioDeviceInput]) { [_captureSession addInput:audioDeviceInput]; } // 7.捕获视频数据输出设备 AVCaptureVideoDataOutput *videoOutput = [[AVCaptureVideoDataOutput alloc] init]; //7.1 设置代理， 捕获视频样品数据 dispatch_queue_t videoQueue = dispatch_queue_create("Video Capure Queue", DISPATCH_QUEUE_SERIAL); [videoOutput setSampleBufferDelegate: self queue:videoQueue]; // 8.设置音频数据输出设备 AVCaptureAudioDataOutput *audioOutput = [[AVCaptureAudioDataOutput alloc] init]; // 8.1 设置代理，捕获音频样品数据 注意：必须是串行队列才能捕获到数据,而且不能为空 dispatch_queue_t audioQueue = dispatch_queue_create("Audio Capure Queue", DISPATCH_QUEUE_SERIAL); [audioOutput setSampleBufferDelegate:self queue:audioQueue]; // 9.添加到会话中 注意：最好要判断是否能添加输入，会话不能添加空的 if ([_captureSession canAddOutput:videoOutput]) { [_captureSession addOutput:videoOutput]; } if ([_captureSession canAddOutput:audioOutput]) { [_captureSession addOutput:audioOutput]; } // 10.获取视屏输入与输出连接，用于分辨音视频数据 _videoConnection = [videoOutput connectionWithMediaType:AVMediaTypeVideo]; // 11.添加视屏预览图层 _previewdLayer = [AVCaptureVideoPreviewLayer layerWithSession:_captureSession]; _previewdLayer.frame = [UIScreen mainScreen].bounds; [self.view.layer insertSublayer:_previewdLayer atIndex:0]; // 12.开启会话 [_captureSession startRunning];}// 根据摄像头方向获取摄像头- (AVCaptureDevice *)getVideoDevice: (AVCaptureDevicePosition)position { NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; for (AVCaptureDevice *device in devices) { if (device.position == position) { return device; } } return nil;}

AVCaptureDevicePositionUnspecified，那么是不能调用摄像头的。typedef NS_ENUM(NSInteger, AVCaptureDevicePosition) { AVCaptureDevicePositionUnspecified = 0, // 不指定 AVCaptureDevicePositionBack = 1, //后置 AVCaptureDevicePositionFront = 2 // 前置}

// 获取输出设备数据，有可能是音频，有可能是视频- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection { if (_videoConnection == connection) { NSLog(@"采集到视屏数据"); }else { NSLog(@"采集到音频数据"); }}

#pragma mark - 切换摄像头- (IBAction)toggleCapture:(id)sender { // 1.获取当前设备方向 AVCaptureDevicePosition cureentPosition = _currentVideoDeviceInput.device.position; // 2.获取需要改变的方向 AVCaptureDevicePosition togglePosition = (cureentPosition == AVCaptureDevicePositionFront ? AVCaptureDevicePositionBack : AVCaptureDevicePositionFront); // 3.获取需要改变的摄像头设备 AVCaptureDevice *toggleDevice = [self getVideoDevice:togglePosition]; // 4.获取需要改变的摄像头输入设备 AVCaptureDeviceInput *toggleDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:toggleDevice error:nil]; // 5.停止会话，否则会有一瞬间的白屏 [_captureSession stopRunning]; // 6.移除之前的摄像头输入设备,否则会崩溃，因为会话里只能有一个摄像头设备 [_captureSession removeInput:_currentVideoDeviceInput]; // 7.添加新的摄像头输入设备 [_captureSession addInput:toggleDeviceInput]; // 8.重新开始会话 [_captureSession startRunning]; // 记录当前摄像头输入设备 //9.重新开始 _currentVideoDeviceInput = toggleDeviceInput;}