How to get AVCaptureStillImageOutput same aspect ratio as the AVCaptureVideoPreviewLayer?

Question

I'm capturing an image using AVFoundation. I'm using AVCaptureVideoPreviewLayer to display the camera feed on screen. This preview layer's frame gets the bounds of a UIView with dynamic dimensions:

AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
[previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
CALayer *rootLayer = [self.cameraFeedView layer];
[rootLayer setMasksToBounds:YES];
CGRect frame = self.cameraFeedView.frame;
[previewLayer setFrame:frame];
previewLayer.frame = rootLayer.bounds;
[rootLayer insertSublayer:previewLayer atIndex:0];

And I'm using AVCaptureStillImageOutput to capture an image:

AVCaptureStillImageOutput *stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
[stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection
                                              completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
                                                  if (imageDataSampleBuffer != NULL) {
                                                      NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
                                                      UIImage *capturedImage = [UIImage imageWithData:imageData];
                                                  }
                                              }];

My problem is that the captured image is at the size of the iPhone camera (1280x960 - front camera), but I need it to be the same aspect ratio as the preview layer. For example, if the size of the preview layer is 150x100, I need the captured image to be 960x640. Is there any solution for this?

http://stackoverflow.com/questions/612131/whats-the-easiest-way-to-resize-optimize-an-image-size-with-the-iphone-sdk — srinivas n, Jul 29 '15 at 12:59
http://stackoverflow.com/questions/17018617/how-to-resize-an-image-in-ios — srinivas n, Jul 29 '15 at 13:00
I tried resizing already, but because the aspect ratio is different, the resized image looks squished. I can crop the image, but isn't there a way to just get the original frame from the preview layer? — 2shy, Jul 29 '15 at 13:13

score 1 · Answer 1 · answered Nov 19 '15 at 09:33

I also enter counter the same problem. You have to crop or resize output still image. But you should notice that output still`s scale and image orientation.

preview layer square frame

CGFloat width = CGRectGetWidth(self.view.bounds);
[self.captureVideoPreviewLayer setFrame:CGRectMake(0, 0, width, width)];
[self.cameraView.layer addSublayer:self.captureVideoPreviewLayer];

calculate cropped image`s frame

[self.captureStillImageOutput captureStillImageAsynchronouslyFromConnection:captureConnection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
    NSData *data = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
    UIImage *image = [[UIImage alloc] initWithData:data];

    CGRect cropRect = CGRectMake((image.size.height - image.size.width) / 2, 0, image.size.width, image.size.width);
    CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], cropRect);
    UIImage *croppedImage = [UIImage imageWithCGImage:imageRef scale:image.scale orientation:image.imageOrientation]; // always UIImageOrientationRight
    CGImageRelease(imageRef);
}];

How to get AVCaptureStillImageOutput same aspect ratio as the AVCaptureVideoPreviewLayer?

1 Answers1