AVCaptureSession のライブ フィードからフレームを取得したいのですが、Apple の AVCam をテスト ケースとして使用しています。AVCamへのリンクは次のとおりです。
https://developer.apple.com/library/ios/samplecode/AVCam/Introduction/Intro.html
それcaptureOutput:didOutputSampleBuffer:fromConnectionが呼び出されていないことがわかりました。なぜ、または何が間違っているのかを知りたいです。
これが私がやったことです：
(1)AVCamViewControllerデリゲートにします
@interface AVCamViewController () <AVCaptureFileOutputRecordingDelegate, AVCaptureVideoDataOutputSampleBufferDelegate>
(2)AVCaptureVideoDataOutputオブジェクトを作成し、セッションに追加しました
AVCaptureVideoDataOutput *videoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
if ([session canAddOutput:videoDataOutput])
{
[session addOutput:videoDataOutput];
}
(3) デリゲート メソッドを追加し、ランダムな文字列をログに記録してテストします
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
NSLog(@"I am called");
}
テスト アプリケーションは動作しますが、captureOutput:didOutputSampleBuffer:fromConnection は呼び出されません。
(4) SO で、viewDidLoad でローカルにあるセッション変数がAVCaptureSession *session = [[AVCaptureSession alloc] init];デリゲートが呼び出されない理由として考えられることを読み、それを AVCamViewController クラスのインスタンス変数にしましたが、まだ呼び出されていません。
これが私がテストしているviewDidLoadメソッドです（AVCamから取得）。メソッドの最後にAVCaptureDataOutputを追加しました：
- (void)viewDidLoad
{
[super viewDidLoad];
// Create the AVCaptureSession
session = [[AVCaptureSession alloc] init];
[self setSession:session];
// Setup the preview view
[[self previewView] setSession:session];
// Check for device authorization
[self checkDeviceAuthorizationStatus];
// In general it is not safe to mutate an AVCaptureSession or any of its inputs, outputs, or connections from multiple threads at the same time.
// Why not do all of this on the main queue?
// -[AVCaptureSession startRunning] is a blocking call which can take a long time. We dispatch session setup to the sessionQueue so that the main queue isn't blocked (which keeps the UI responsive).
dispatch_queue_t sessionQueue = dispatch_queue_create("session queue", DISPATCH_QUEUE_SERIAL);
[self setSessionQueue:sessionQueue];
dispatch_async(sessionQueue, ^{
[self setBackgroundRecordingID:UIBackgroundTaskInvalid];
NSError *error = nil;
AVCaptureDevice *videoDevice = [AVCamViewController deviceWithMediaType:AVMediaTypeVideo preferringPosition:AVCaptureDevicePositionBack];
AVCaptureDeviceInput *videoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];
if (error)
{
NSLog(@"%@", error);
}
if ([session canAddInput:videoDeviceInput])
{
[session addInput:videoDeviceInput];
[self setVideoDeviceInput:videoDeviceInput];
dispatch_async(dispatch_get_main_queue(), ^{
// Why are we dispatching this to the main queue?
// Because AVCaptureVideoPreviewLayer is the backing layer for AVCamPreviewView and UIView can only be manipulated on main thread.
// Note: As an exception to the above rule, it is not necessary to serialize video orientation changes on the AVCaptureVideoPreviewLayer’s connection with other session manipulation.
[[(AVCaptureVideoPreviewLayer *)[[self previewView] layer] connection] setVideoOrientation:(AVCaptureVideoOrientation)[self interfaceOrientation]];
});
}
AVCaptureDevice *audioDevice = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];
AVCaptureDeviceInput *audioDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:&error];
if (error)
{
NSLog(@"%@", error);
}
if ([session canAddInput:audioDeviceInput])
{
[session addInput:audioDeviceInput];
}
AVCaptureMovieFileOutput *movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];
if ([session canAddOutput:movieFileOutput])
{
[session addOutput:movieFileOutput];
AVCaptureConnection *connection = [movieFileOutput connectionWithMediaType:AVMediaTypeVideo];
if ([connection isVideoStabilizationSupported])
[connection setEnablesVideoStabilizationWhenAvailable:YES];
[self setMovieFileOutput:movieFileOutput];
}
AVCaptureStillImageOutput *stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
if ([session canAddOutput:stillImageOutput])
{
[stillImageOutput setOutputSettings:@{AVVideoCodecKey : AVVideoCodecJPEG}];
[session addOutput:stillImageOutput];
[self setStillImageOutput:stillImageOutput];
}
AVCaptureVideoDataOutput *videoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
[videoDataOutput setSampleBufferDelegate:self queue:sessionQueue];
if ([session canAddOutput:videoDataOutput])
{
NSLog(@"Yes I can add it");
[session addOutput:videoDataOutput];
}
});
}
- (void)viewWillAppear:(BOOL)animated
{
dispatch_async([self sessionQueue], ^{
[self addObserver:self forKeyPath:@"sessionRunningAndDeviceAuthorized" options:(NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew) context:SessionRunningAndDeviceAuthorizedContext];
[self addObserver:self forKeyPath:@"stillImageOutput.capturingStillImage" options:(NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew) context:CapturingStillImageContext];
[self addObserver:self forKeyPath:@"movieFileOutput.recording" options:(NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew) context:RecordingContext];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(subjectAreaDidChange:) name:AVCaptureDeviceSubjectAreaDidChangeNotification object:[[self videoDeviceInput] device]];
__weak AVCamViewController *weakSelf = self;
[self setRuntimeErrorHandlingObserver:[[NSNotificationCenter defaultCenter] addObserverForName:AVCaptureSessionRuntimeErrorNotification object:[self session] queue:nil usingBlock:^(NSNotification *note) {
AVCamViewController *strongSelf = weakSelf;
dispatch_async([strongSelf sessionQueue], ^{
// Manually restarting the session since it must have been stopped due to an error.
[[strongSelf session] startRunning];
[[strongSelf recordButton] setTitle:NSLocalizedString(@"Record", @"Recording button record title") forState:UIControlStateNormal];
});
}]];
[[self session] startRunning];
});
}
誰かが理由とそれを修正する方法についての提案を教えてもらえますか?