我们不能使用单个
AVCaptureSession
对象来处理多个
AVCaptureVideoDataOutput
对象。
你可以创建多个
AVCaptureSession
对象和多个
AVCaptureVideoDataOutput
对象。你可以创建两种不同的
AVCaptureVideoDataOutput
和
AVCaptureSession
设置,然后在应用程序中一个接一个地使用它们,这样你就能够实现目标。
在我的情况下,我需要同时捕获前后摄像头的图像。
我按照以下方式为
AVCaptureVideoDataOutput
和
AVCaptureSession
创建了两个不同的对象。
@property bool isFrontRecording;
@property (strong, nonatomic) AVCaptureDeviceInput *videoInputBack;
@property (strong, nonatomic) AVCaptureStillImageOutput *imageOutputBack;
@property (strong, nonatomic) AVCaptureSession *sessionBack;
@property bool isBackRecording;
@property (strong, nonatomic) AVCaptureDeviceInput *videoInputFront;
@property (strong, nonatomic) AVCaptureStillImageOutput *imageOutputFront;
@property (strong, nonatomic) AVCaptureSession *sessionFront;
现在,在视图加载时,我首先设置了后置摄像头,并为两个会话设置了开始录制或未开始录制的标志。
- (void)viewDidLoad {
[super viewDidLoad];
[self setupBackAVCapture];
self.isFrontRecording = NO;
self.isBackRecording = NO;
}
- (void)setupBackAVCapture
{
NSError *error = nil;
self.sessionBack = [[AVCaptureSession alloc] init];
self.sessionBack.sessionPreset = AVCaptureSessionPresetPhoto;
AVCaptureDevice *camera = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
self.videoInputBack = [[AVCaptureDeviceInput alloc] initWithDevice:camera error:&error];
[self.sessionBack addInput:self.videoInputBack];
self.imageOutputBack = [[AVCaptureStillImageOutput alloc] init];
[self.sessionBack addOutput:self.imageOutputBack];
}
现在,无论何时用户开始进行照片捕捉,我们将使用以下代码捕获前置摄像头的照片。
- (IBAction)buttonCapture:(id)sender {
[self takeBackPhoto];
}
- (void)takeBackPhoto
{
[self.sessionBack startRunning];
if (!self.isFrontRecording) {
self.isFrontRecording = YES;
AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
AVCaptureConnection *videoConnection = [self.imageOutputBack connectionWithMediaType:AVMediaTypeVideo];
if (videoConnection == nil) {
return;
}
[self.imageOutputBack
captureStillImageAsynchronouslyFromConnection:videoConnection
completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
if (imageDataSampleBuffer == NULL) {
return;
}
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
UIImageWriteToSavedPhotosAlbum(image, self, nil, nil);
[self.imageView setImage:image];
[self.sessionBack stopRunning];
[self setupFrontAVCapture];
[self takeFrontPhoto];
}];
self.isFrontRecording = NO;
}
}
一旦后置图像被捕获,我们将使用
setupFrontAVCapture 方法设置会话以捕获前置图像,然后使用
takeFrontPhoto 方法捕获前置图像,如下所示。
- (void)setupFrontAVCapture
{
NSError *error = nil;
self.sessionFront = [[AVCaptureSession alloc] init];
self.sessionFront.sessionPreset = AVCaptureSessionPresetPhoto;
AVCaptureDevice *camera = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
camera = [self cameraWithPosition:AVCaptureDevicePositionFront];
self.videoInputFront = [[AVCaptureDeviceInput alloc] initWithDevice:camera error:&error];
[self.sessionFront addInput:self.videoInputFront];
self.imageOutputFront = [[AVCaptureStillImageOutput alloc] init];
[self.sessionFront addOutput:self.imageOutputFront];
}
- (void)takeFrontPhoto
{
[self.sessionFront startRunning];
if (!self.isBackRecording) {
self.isBackRecording = YES;
AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
AVCaptureConnection *videoConnection = [self.imageOutputFront connectionWithMediaType:AVMediaTypeVideo];
if (videoConnection == nil) {
return;
}
[self.imageOutputFront
captureStillImageAsynchronouslyFromConnection:videoConnection
completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
if (imageDataSampleBuffer == NULL) {
return;
}
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
UIImageWriteToSavedPhotosAlbum(image, self, nil, nil);
[self.imageViewBack setImage:image];
[self.sessionFront stopRunning];
}];
self.isBackRecording = NO;
}
}
通过这种方式,您可以使用两个不同的AVCaptureSession
和AVCaptureStillImageOutput
对象,从而实现您的目标。
如果您有任何疑问,请告诉我。