Better performance for ffmpeg decoding editing image contrast for every frame

Question

i'm developing an rtsp player using ffmpeg library and i must edit contrast image for every frame of video, searching the web i found this code for edit contrast :

- (UIImage*)contrast
{    
    CIImage *beginImage = [CIImage imageWithCGImage:[self CGImage]];
    CIContext *context = [CIContext contextWithOptions:nil];

    CIFilter *filter = [CIFilter filterWithName:@"CISepiaTone" 
                                  keysAndValues: kCIInputImageKey, beginImage, 
                        @"inputIntensity", [NSNumber numberWithFloat:0.8], nil];
    CIImage *outputImage = [filter outputImage];

    CGImageRef cgimg = 
    [context createCGImage:outputImage fromRect:[outputImage extent]];
    UIImage *newImg = [UIImage imageWithCGImage:cgimg];

    self = newImg;

    CGImageRelease(cgimg);
    return self;
}

it works perfectly, but on iPad i lose performance and when decoding video are show a lot of noise on screen. There is a better way in performance to modify contrast for image??

Answer 1

Yes, there is a better way... Use opengl es 2.0 shaders, btw this hard work will be done on GPU...