Iphone – Immediately freeze-frame an AVCaptureSession

avfoundationiphone

I'm building an app that allows users to snap pictures using the iPhone camera, and am using AVFoundation when it's available (iOS4) so users can use the tap-to-focus feature, even with a custom overlay.

The problem I'm having is that captureStillImageAsynchronouslyFromConnection takes several seconds to complete, during which I'd like to freeze-frame the main video feed so there isn't a confusing state where the video is still running, but the user has snapped a photo (and the camera shutter sound has gone off).

I've tried calling [session stopRunning] right after I request a still image capture, but this leads to unpredictable results; the still image completion block often doesn't get fired in that case.

Any ideas on how I could have the video preview layer "pause" as soon as the shutter is hit?

Best Answer

You just need to set your captureVideoPreviewLayer.connection.enabled = NO;

For details please see my answer here:

AVCaptureSession pause?

Related Solutions

Ios – AVFoundation, how to turn off the shutter sound when captureStillImageAsynchronouslyFromConnection

I used this code once to capture iOS default shutter sound (here is list of sound file names https://github.com/TUNER88/iOSSystemSoundsLibrary):

NSString *path = @"/System/Library/Audio/UISounds/photoShutter.caf";
NSString *docs = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSData *data = [NSData dataWithContentsOfFile:path];
[data writeToFile:[docs stringByAppendingPathComponent:@"photoShutter.caf"] atomically:YES];

Then I used third-party app to extract photoShutter.caf from Documents directory (DiskAid for Mac). Next step I opened photoShutter.caf in Audacity audio editor and applied inversion effect, it looks like this on high zoom:

enter image description here

Then I saved this sound as photoShutter2.caf and tried to play this sound right before captureStillImageAsynchronouslyFromConnection:

static SystemSoundID soundID = 0;
if (soundID == 0) {
    NSString *path = [[NSBundle mainBundle] pathForResource:@"photoShutter2" ofType:@"caf"];
    NSURL *filePath = [NSURL fileURLWithPath:path isDirectory:NO];
    AudioServicesCreateSystemSoundID((__bridge CFURLRef)filePath, &soundID);
}
AudioServicesPlaySystemSound(soundID);

[self.stillImageOutput captureStillImageAsynchronouslyFromConnection:
...

And this really works! I runs test several times, every time I hear no shutter sound :)

You can get already inverted sound, captured on iPhone 5S iOS 7.1.1 from this link: https://www.dropbox.com/s/1echsi6ivbb85bv/photoShutter2.caf

Iphone – How to take square picture in iphone with avFoundation like in Instagram app

You should probably be resizing your UIImage by creating a new context. Examples below

.....
UIImage *image = [[UIImage alloc] initWithData:imageData];
UIImage *tempImage = nil;
CGSize targetSize = CGSizeMake(400,400);
UIGraphicsBeginImageContext(targetSize);

CGRect thumbnailRect = CGRectMake(0, 0, 0, 0);
thumbnailRect.origin = CGPointMake(0.0,0.0);
thumbnailRect.size.width  = targetSize.width;
thumbnailRect.size.height = targetSize.height;

[image drawInRect:thumbnailRect];

tempImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

// tmpImage is resized to 400x400

Hope this helps !

Best Answer

Related Solutions

Ios – AVFoundation, how to turn off the shutter sound when captureStillImageAsynchronouslyFromConnection

Iphone – How to take square picture in iphone with avFoundation like in Instagram app

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