UIImage unkomprimiert von AVCaptureStillImageOutput

Question

Das ist, was ich bisher für die Konfiguration der Kamera versucht:

AVCaptureSession *session = [[AVCaptureSession alloc] init]; 
    [session setSessionPreset:AVCaptureSessionPresetInputPriority]; 

    AVCaptureDevice *videoDevice = [AVCamViewController deviceWithMediaType:AVMediaTypeVideo preferringPosition:AVCaptureDevicePositionBack]; 

    NSError *errorVideo; 

    AVCaptureDeviceFormat *deviceFormat = nil; 
    for (AVCaptureDeviceFormat *format in videoDevice.formats) { 
     CMVideoDimensions dim = CMVideoFormatDescriptionGetDimensions(format.formatDescription); 

     if (dim.width == 2592 && dim.height == 1936) { 
      deviceFormat = format; 
      break; 
     } 
    } 

    [videoDevice lockForConfiguration:&errorVideo]; 
    if (deviceFormat) { 
     videoDevice.activeFormat = deviceFormat; 

     if ([videoDevice isExposureModeSupported:AVCaptureExposureModeContinuousAutoExposure]) { 
      [videoDevice setExposureMode:AVCaptureExposureModeContinuousAutoExposure]; 
     } 

     if ([videoDevice isAutoFocusRangeRestrictionSupported]) { 
      [videoDevice setAutoFocusRangeRestriction:AVCaptureAutoFocusRangeRestrictionFar]; 
     } 
    } 
    [videoDevice unlockForConfiguration]; 

    AVCaptureDeviceInput *videoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error]; 

    if ([session canAddInput:videoDeviceInput]) { 
     [session addInput:videoDeviceInput]; 
    } 

    AVCaptureStillImageOutput *stillImageOutput = [[AVCaptureStillImageOutput alloc] init]; 

    if ([session canAddOutput:stillImageOutput]) { 
     [stillImageOutput setOutputSettings:@{(id)kCVPixelBufferPixelFormatTypeKey:@(kCVPixelFormatType_32BGRA)}]; 
     [session addOutput:stillImageOutput]; 
    } 

Dies ist, was ich versuchte, die UIImage aus dem CMSamplebuffer für immer:

[[self stillImageOutput] captureStillImageAsynchronouslyFromConnection:connection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) { 

     if (imageDataSampleBuffer && !error) { 
      dispatch_async(dispatch_get_main_queue(), ^{ 
       UIImage *image = [self imageFromSampleBuffer:imageDataSampleBuffer]; 
      }); 
     } 
    }]; 

Dies ist ein Apple-Beispielcode:

- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer{ 
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 

CVPixelBufferLockBaseAddress(imageBuffer, 0); 

void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer); 

// Get the number of bytes per row for the pixel buffer 
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
// Get the pixel buffer width and height 
size_t width = CVPixelBufferGetWidth(imageBuffer); 
size_t height = CVPixelBufferGetHeight(imageBuffer); 



// Create a device-dependent RGB color space 
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 

// Create a bitmap graphics context with the sample buffer data 
CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8, 
              bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); 
// Create a Quartz image from the pixel data in the bitmap graphics context 
CGImageRef quartzImage = CGBitmapContextCreateImage(context); 
// Unlock the pixel buffer 
CVPixelBufferUnlockBaseAddress(imageBuffer,0); 


// Free up the context and color space 
CGContextRelease(context); 
CGColorSpaceRelease(colorSpace); 

// Create an image object from the Quartz image 
UIImage *image = [UIImage imageWithCGImage:quartzImage]; 

// Release the Quartz image 
CGImageRelease(quartzImage); 

return (image); 
} 

Aber das Bild ist immer Null. Nach einigen Debugging. Ich fand, dass diese Funktion immer Null zurückgibt CMSampleBufferGetImageBuffer(sampleBuffer);

Kann jemand helfen?

Answer 1

Dies ist, weil der CMSampleBufferRef sofort bearbeitet werden muss, da es sehr schnell und effizient freigegeben wird.

Hier ist mein Code für die Erzeugung des Bildes:

let connection = imageFileOutput.connectionWithMediaType(AVMediaTypeVideo) 

if connection != nil { 
    imageFileOutput.captureStillImageAsynchronouslyFromConnection(connection) { [weak self] (buffer, err) -> Void in 
     if CMSampleBufferIsValid(buffer) { 
      let imageDataJpeg = self?.imageFromSampleBuffer(buffer) 
     } else { 
      print(err) 
     } 
    } 
} 

Wie man sehen kann ich es in ein Bild drehen, während noch in den Rahmen dieser Funktion. Sobald es ein Bild ist, sende ich es zur Verarbeitung ab.