I am trying to add CIFilters to video. But I change the values using UISliders because of AVPlayer take time to play filter added video. I search of this issue, UISlider values continuously changing and it takes float values as well. Because of every time filter add to video and play. I want to know how to change values of CIFilter and without delay of AVPlayer when slider value change continuously.
float value = sender.value;
CIFilter *filter = [CIFilter filterWithName:@"CIColorControls"];
AVVideoComposition *composition = [AVVideoComposition videoCompositionWithAsset:tempAVAsset applyingCIFiltersWithHandler:
^(AVAsynchronousCIImageFilteringRequest *request){
NSError *err = nil;
CIImage *filtered = [request.sourceImage imageByClampingToExtent];
[filter setDefaults];
[filter setValue:filtered forKey:kCIInputImageKey];
[filter setValue:[NSNumber numberWithFloat:0.00] forKey:@"inputSaturation"];
[filter setValue:[NSNumber numberWithFloat:0.00] forKey:@"inputBrightness"];
[filter setValue:[NSNumber numberWithFloat:value] forKey:@"inputContrast"];
CIImage *output = [filter.outputImage imageByCroppingToRect:request.sourceImage.extent];
if (filtered)
[request finishWithImage:output context:nil];
else
[request finishWithError:err];
}];
You can just change the filter parameter outside of your composition block when the slider value changes and don't re-set it inside the block. So just do
[adjustFilter setValue:[NSNumber numberWithFloat:sender.value] forKey:@"inputContrast"];
inside your valueChanged
callback instead of inside the composition block. This way the filter always gets the most current value and will use it for the next video frame.
Edit:
Here are some parts of a possible implementation inside a view controller:
@interface DemoViewController ()
@property (strong, nonatomic) CIFilter *filter;
@property (strong, nonatomic) AVPlayer *player;
@property (strong, nonatomic) AVAsset *tempAVAsset;
@end
@implementation DemoViewController
- (void)viewDidLoad {
[super viewDidLoad];
// setup filter
self.filter = [CIFilter filterWithName:@"CIColorControls"];
[self.filter setDefaults];
[self.filter setValue:[NSNumber numberWithFloat:0.00] forKey:@"inputSaturation"];
[self.filter setValue:[NSNumber numberWithFloat:0.00] forKey:@"inputBrightness"];
AVVideoComposition *composition = [AVVideoComposition videoCompositionWithAsset:self.tempAVAsset applyingCIFiltersWithHandler:
^(AVAsynchronousCIImageFilteringRequest *request){
NSError *err = nil;
CIImage *filtered = [request.sourceImage imageByClampingToExtent];
[self.filter setValue:filtered forKey:kCIInputImageKey];
CIImage *output = [self.filter.outputImage imageByCroppingToRect:request.sourceImage.extent];
if (filtered)
[request finishWithImage:output context:nil];
else
[request finishWithError:err];
}
];
// setup player with composition
// ...
}
- (IBAction)sliderValueChanged:(UISlider*)sender
{
// get the new slider value and assign it to the filter
[self.filter setValue:[NSNumber numberWithFloat:sender.value] forKey:@"inputContrast"];
}
@end