黑灰濾鏡预愤，處理時內(nèi)存會彪殴泰，但還在可接受范圍
self.avPlayerItem.videoComposition = [AVVideoComposition videoCompositionWithAsset:self.avAsset applyingCIFiltersWithHandler: ^(AVAsynchronousCIImageFilteringRequest *request){
@autoreleasepool {
NSError *err = nil;
CIImage *ciImage = request.sourceImage;
//灰色濾鏡
CIFilter *filter = [CIFilter filterWithName:@"CIColorMonochrome"];
[filter setValue:ciImage forKey:kCIInputImageKey];
[filter setValue:[CIColor colorWithRed:0.7 green:0.7 blue:0.7] forKey:kCIInputColorKey];
[filter setValue:@1.0 forKey:kCIInputIntensityKey];
CIImage *outputImage = filter.outputImage;
if (outputImage)
[request finishWithImage:outputImage context:nil];
else
[request finishWithError:err];
outputImage = nil;
}
}];
