         _currentColorFilter = newFilter
         let shaderName = (_colorFilters?[newFilter]["Shader"] as? String) ?? "yuv_rgb"
         var convolution = [Float32]()
-        if let param = _colorFilters?[newFilter]["Convolution"] as? [NSNumber] {
-            if param.count == 9 {
-                for i in 0...8 {
-                    convolution.append(Float32(param[i].floatValue))
-                }
+        if let param = _colorFilters?[newFilter]["Convolution"] as? [NSNumber] where param.count == 9 {
+            for i in 0...8 {
+                convolution.append(Float32(param[i].floatValue))
             }
         }
         

        set {
            if let videoFilter = _videoFilters {
                for i in 0..<videoFilter.count {
                    if let name = videoFilter[i]["Name"] as? String {
                        if name == newValue {
                            setVideoFilterIndex(i)
                            return;
                        }
                    }
                }
            }

        set {
            if let colorFilters = _colorFilters {
                for i in 0..<colorFilters.count {
                    if let name = colorFilters[i]["Name"] as? String where name == newValue {
                        setColorFilterIndex(i)
                        return;
                    }
                }
            }
