Is there any way to improve time between shots with AVCaptureStillImageOutput?

Question

I currently use the following code to shoot a series of images:

- (void)shootSeries:(int)photos {
    if(photos == 0) {
        [self mergeImages];
    } else {
        [output captureStillImageAsynchronouslyFromConnection:connection completionHandler:
            ^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
                NSLog(@"Shot picture %d.", 7 - photos);
                [self shootSeries:(photos - 1)];

                CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(imageDataSampleBuffer);

                CVPixelBufferLockBaseAddress(pixelBuffer, 0);
                int dataSize = CVPixelBufferGetDataSize(pixelBuffer);
                CFDataRef data = CFDataCreate(NULL, (const UInt8 *)CVPixelBufferGetBaseAddress(pixelBuffer), dataSize);
                CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);

                CGDataProviderRef dataProvider = CGDataProviderCreateWithCFData(data);
                CFRelease(data);

                CGImageRef image = CGImageCreate(CVPixelBufferGetWidth(pixelBuffer),
                                                 CVPixelBufferGetHeight(pixelBuffer),
                                                 8, 32,
                                                 CVPixelBufferGetBytesPerRow(pixelBuffer),
                                                 colorspace,
                                                 kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Little,
                                                 dataProvider, NULL, true, kCGRenderingIntentDefault);
                CFRelease(dataProvider);

                CFArrayAppendValue(shotPictures, image);
                CFRelease(image);
            }];
    }
}

While this works rather well it is very slow. How come apps like ClearCam can shoot pictures much faster in series than this and how can I do it too?

Answer 1

After capturing the image, store the sample buffer in a CFArray, and once you're done taking all your phones, THEN convert them to images (or in your case CGImageRefs).