Image filtering leads to high memory consumption and crash

Question

I am using the following code for applying image filters. In my app I am filtering for brightness, contrast and saturation. I am using three separate sliders each to change the values. As I continue to move the values, the memory consumption goes over 1.5 gb and crashes. Is there a way to reduce this memory consumption for a crash free implementation?

(void)setBrightnessAndContrastOf:(UIImage *)image { // forTarget:(UIImageView *)imgView {

    if (!image) {
        return;
    }

    CIImage *inputImage = [[CIImage alloc] initWithImage:image];
    CIFilter *exposureAdjustmentFilter = [CIFilter filterWithName:@"CIColorControls"];
    [exposureAdjustmentFilter setDefaults];
    [exposureAdjustmentFilter setValue:inputImage forKey:@"inputImage"];

    [exposureAdjustmentFilter setValue:[NSNumber numberWithFloat:self.contrastValue] forKey:@"inputContrast"]; //default = 1.00
    [exposureAdjustmentFilter setValue:[NSNumber numberWithFloat:self.brightnessValue] forKey:@"inputBrightness"]; //default = 0.00
    [exposureAdjustmentFilter setValue:[NSNumber numberWithFloat:self.saturationValue] forKey:@"inputSaturation"]; //default = 1.00
    CIImage *outputImage = [exposureAdjustmentFilter valueForKey:@"outputImage"];

    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef tempImage = [context createCGImage:outputImage fromRect:[outputImage extent]];

    UIImage *newImage = [UIImage imageWithCGImage:tempImage];

    [imageView performSelectorOnMainThread:@selector(setImage:) withObject:newImage waitUntilDone:NO];
    CGImageRelease(tempImage);

    inputImage = nil;
    context = nil;
    outputImage = nil;
    exposureAdjustmentFilter = nil;
}

The compiler does not automatically manage the lifetimes of Core Foundation objects.That is why you are supposed to release them. PS: you are doing that! Now the breakpoint test.... — Khaled Barazi, Oct 31 '13 at 11:41
@Spectravideo328 I tried the breakpoint test,it didnt notice the break point.Is there a solution to solve this — Nassif, Oct 31 '13 at 11:54

metsburg · Answer 1 · 2013-10-31T11:47:30.763

You're not supposed to do heavy image manipulation inside the main thread. Unless you've already implemented multithreading (which is not mentioned in your code snippet), please do so.

You might try:

dispatch_queue_t backgroundQueue = dispatch_queue_create("com.yourorg", DISPATCH_QUEUE_SERIAL);
dispatch_queue_t mainQueue = dispatch_get_main_queue();
dispatch_async(backgroundQueue, ^
                   {
     // setBrightnessAndContrastOf method goes here

        dispatch_sync(mainQueue, ^ {

               //notify main thread about process status
                      });

          });

Since you're using ARC, crashes due to over consumption of memory is not very likely. However, if you block the main thread for too long, watchdog timer takes it out through the backdoor and shoots it right in the head.

Use instruments to monitor your heap size and try to find out the root cause.

score 0 · Answer 2 · answered Oct 31 '13 at 11:57

0

I am not sure what your setImage method is doing but I would move CGImageRelease(tempImage) before the performSelector.

answered Oct 31 '13 at 11:57

Khaled Barazi

8,681
6
42
62

i am just assigning the created image to an imageview – Nassif Oct 31 '13 at 12:04
did you test the move? – Khaled Barazi Oct 31 '13 at 12:11
How often are you calling : setBrightnessAndContrastOf? Is this tied to a video feed? In other words, is this method getting called continuously or on request? – Khaled Barazi Oct 31 '13 at 12:35
loading an image from the server,simultanouesly if i change the slideri setbrightnessandcontrast is called – Nassif Oct 31 '13 at 12:40
so would your memory consumption keep growing even if you loaded only one image from the server and change the slider only once? – Khaled Barazi Oct 31 '13 at 12:41

Image filtering leads to high memory consumption and crash

2 Answers2