Ios AVCaptureStillImageOutput从不调用完成处理程序
下面的代码不起作用。怎么了Ios AVCaptureStillImageOutput从不调用完成处理程序,ios,camera,avfoundation,video-capture,Ios,Camera,Avfoundation,Video Capture,下面的代码不起作用。怎么了 AVCaptureDevice * videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; AVCaptureDeviceInput * videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil]; AVCaptureSession * captureSession = [
AVCaptureDevice * videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput * videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil];
AVCaptureSession * captureSession = [[AVCaptureSession alloc] init];
captureSession.sessionPreset = AVCaptureSessionPresetMedium;
if (![captureSession canAddInput:videoInput])
NSLog(@"Can't add input");
[captureSession addInput:videoInput];
self.stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
[self.stillImageOutput setOutputSettings:@{AVVideoCodecKey:AVVideoCodecJPEG}];
if (![captureSession canAddOutput:videoInput])
NSLog(@"Can't add output");
[captureSession addOutput:self.stillImageOutput];
[self.stillImageOutput captureStillImageAsynchronouslyFromConnection:[self.stillImageOutput.connections lastObject]
completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error)
{
NSLog(@"!!!");
if (imageDataSampleBuffer == NULL)
{
NSLog(@"%@", error);
return;
}
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
self.imageView.image = image;
}];
// Creating preview layer
self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:captureSession];
self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
self.previewLayer.frame = self.view.layer.bounds;
[self.view.layer addSublayer:self.previewLayer];
[captureSession startRunning];
AVCaptureVideoPreviewLayer工作得很好,但AVCaptureStillImageOutput根本不调用完成处理程序…这很好:
- (void)viewDidLoad
{
[super viewDidLoad];
AVCaptureDevice * videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput * videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil];
AVCaptureSession * captureSession = [[AVCaptureSession alloc] init];
captureSession.sessionPreset = AVCaptureSessionPresetMedium;
[captureSession addInput:videoInput];
[captureSession addOutput:self.stillImageOutput];
[captureSession startRunning];
// Creating preview layer
self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:captureSession];
self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
self.previewLayer.frame = self.view.layer.bounds;
[self.view.layer insertSublayer:self.previewLayer atIndex:0];
}
- (void)timerFired:(NSTimer *)timer
{
[self.stillImageOutput captureStillImageAsynchronouslyFromConnection:[self.stillImageOutput.connections lastObject]
completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error)
{
NSLog(@"!!!");
if (imageDataSampleBuffer == NULL)
NSLog(@"%@", error);
NSData * imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
UIImage * image = [[UIImage alloc] initWithData:imageData];
self.imageView.image = image;
}];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(timerFired:) userInfo:nil repeats:YES];
}
您需要用一种方法设置和启动会话, 然后使用单独的捕获方法:
/////////////////////////////////////////////////
////
//// Utility to find front camera
////
/////////////////////////////////////////////////
-(AVCaptureDevice *) frontFacingCameraIfAvailable{
NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
AVCaptureDevice *captureDevice = nil;
for (AVCaptureDevice *device in videoDevices){
if (device.position == AVCaptureDevicePositionFront){
captureDevice = device;
break;
}
}
// couldn't find one on the front, so just get the default video device.
if (!captureDevice){
captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
}
return captureDevice;
}
/////////////////////////////////////////////////
////
//// Setup Session, attach Video Preview Layer
//// and Capture Device, start running session
////
/////////////////////////////////////////////////
-(void) setupCaptureSession {
AVCaptureSession *session = [[AVCaptureSession alloc] init];
session.sessionPreset = AVCaptureSessionPresetMedium;
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
[self.view.layer addSublayer:captureVideoPreviewLayer];
NSError *error = nil;
AVCaptureDevice *device = [self frontFacingCameraIfAvailable];
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (!input) {
// Handle the error appropriately.
NSLog(@"ERROR: trying to open camera: %@", error);
}
[session addInput:input];
self.stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
[self.stillImageOutput setOutputSettings:outputSettings];
[session addOutput:self.stillImageOutput];
[session startRunning];
}
/////////////////////////////////////////////////
////
//// Method to capture Still Image from
//// Video Preview Layer
////
/////////////////////////////////////////////////
-(void) captureNow {
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in self.stillImageOutput.connections) {
for (AVCaptureInputPort *port in [connection inputPorts]) {
if ([[port mediaType] isEqual:AVMediaTypeVideo] ) {
videoConnection = connection;
break;
}
}
if (videoConnection) { break; }
}
NSLog(@"about to request a capture from: %@", self.stillImageOutput);
__weak typeof(self) weakSelf = self;
[self.stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error) {
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
[weakSelf displayImage:image];
}];
}
“以单独的方法执行”解决此问题的唯一原因是,它具有在控制器中保留AVCaptureSession的副作用。我认为AVCaptureStillImageOutput中有一个bug,使得它在自动引用计数模式下无法跟踪AVCaptureSession。啊,说得对。是的,一位同事&我正试图让它像你上周五尝试的那样工作,但没有成功。我一直到凌晨,发现最好单独初始化AVCaptureSession。祝你好运!我正在尝试在swift中执行相同的操作,但它不起作用…..是否有原因使其不起作用..我有相同的代码….在我的示例中,stillImageOutput.connections为nil,因为我分配了AVCaptureSession和AVCaptureVideoPreviewLayer两次,所以只添加了检查会话==nil,然后只执行[[AvCaptureSillImageOutput alloc]init]和所有静态图像输出预设