音视频录制

如果要使用系统的相机UI来照相或者是拍摄视频什么的可以直接使用UIImagePickerController

由此可以看出来我们要使用这个框架的话需要有一个AVCaptureDevice,通过Device来获取input(输入.音频输入、视频输入等).然后通过AVCaptureSession传输给AVCaptureOutput(输出).

0 权限

不管是macOS还是iOS设备,都需要在info.plist内添加对应的键.恰好键的名字(key)是一样的.

NSMicrophoneUsageDescription 使用麦克风权限,value是使用麦克风的说明

NSCameraUsageDescription 使用相机权限,value是使用相机的说明.

PS:其实不加权限的说明也没什么.反正Debug的时候崩溃会给出原因.

在使用录制设备前需要检测权限

// Request permission to access the camera and microphone.
switch ([AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo]) {
    case AVAuthorizationStatusAuthorized: {
		/// 用户已授权
		/// 设置AVCaptureSession
        [self setupCaptureSession];
    }
        break;
    case AVAuthorizationStatusNotDetermined: {
		/// 该应用尚未请求过权限
        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {/// 请求摄像头权限
            if (granted) {
            	///设置AVCaptureSession
                [self setupCaptureSession];
            }
        }];
    }
        break;
    case AVAuthorizationStatusDenied: {
		/// 用户拒绝授权
    }
	    break;
    case AVAuthorizationStatusRestricted: {
        /// 用户无法授予访问权限(访问限制)
    }
	    break;
}

捕获的照片的存储

iOS需要在info.plist中添加NSPhotoLibraryUsageDescriptionkey.并且说明为什么要访问照片库

请求写入权限

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {

}];

音视频的录制

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从苹果的这张图可以看出来.类似AVAudioSession管理音频.AVCaptureSession管理CaptureDevice(抓取设备.可以是音频抓取设备麦克风也可以是摄像头等).途径AVCaptureSession后输出的可能是PhotoOutput也可能是MovieFileOutPut或者是VideoPreviewLayer.

1.创建捕获会话实例

self.captureSession = [[AVCaptureSession alloc] init];

2.获取捕获设备实例

self.captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

3.通过捕获设备类获取捕获设备输入实例.并且添加到captureSessiono中.

/// 添加视频输入
self.captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
self.deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:self.captureDevice error:nil];
if ([self.captureSession canAddInput:self.deviceInput]) {
	[self.captureSession addInput:self.deviceInput];
} else {
        
}

/// 添加音频输入
self.captureDeviceVoice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
self.deviceInputVoice = [AVCaptureDeviceInput deviceInputWithDevice:self.captureDeviceVoice error:nil];
if ([self.captureSession canAddInput:self.deviceInputVoice]) {
	[self.captureSession addInput:self.deviceInputVoice];
}

录制画面的预览

录制画面的预览我们需要使用AVCaptureVideoPreviewLayer这个类.

self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];
self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[self.view.layer addSublayer:self.previewLayer];
self.previewLayer.frame = self.view.bounds;

注意的是,如果session没有调用startRunning.预览画面是不会有东西滴.

音视频的输出

/// 设置文件输出
self.movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];;
if ([self.captureSession canAddOutput:self.movieFileOutput]) {
	[self.captureSession addOutput:self.movieFileOutput];
}

PS:这里偷个懒,用一个BOOL属性记录一下是否在录制

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    if (self.isRecording) {
        [self.movieFileOutput stopRecording];
        self.isRecording = NO;
    } else {
        [self.movieFileOutput startRecordingToOutputFileURL:[NSURL fileURLWithPath:[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject stringByAppendingPathComponent:@"/视频录制.mp4"]] recordingDelegate:self];
        self.isRecording = YES;
    }
}