diff --git a/filter.cc b/filter.cc
index 4080ef0..0b2e8d0 100644
--- a/filter.cc
+++ b/filter.cc
@@ -112,7 +112,7 @@ void Filter::ComposeOutput() {
 				idx = 3 * (inFrame.w * y + x);
 
 				for (i = 0; i < 3; i++)
-					pixd[idx+i] = ((FACTOR-1) * pixd[idx+i]/FACTOR) + (pixs[idx+i] / FACTOR);
+					pixd[idx+i] = ((FACTOR-1.0) * (float)pixd[idx+i]/FACTOR) + (float)(pixs[idx+i] / FACTOR);
 			}
 	}
 }
diff --git a/videoframe.cc b/videoframe.cc
index f55a516..c7acd9f 100644
--- a/videoframe.cc
+++ b/videoframe.cc
@@ -61,7 +61,7 @@ void VideoFrame::CopyFrom(VideoFrame *source) {
 
 
 void VideoFrame::CopyFrom(FloatImage *source) {
-	float min, max;
+	float min, max, f;
 	int x, y, i, idx;
 	unsigned char v;
 
@@ -80,7 +80,10 @@ void VideoFrame::CopyFrom(FloatImage *source) {
 	for (y = 0; y < h; y++) for (x = 0; x < w; x++)
 		for (i = 0; i < 3; i++) {
 			idx = 3 * (y * w + x);
-			v = (float)(256.0 * (source->data[idx+i]-min) / (max-min));
+			f = (float)(255.0 * (source->data[idx+i]-min) / (max-min));
+			if (f < 0.0) v = 0;
+			else if (f > 255.0) v = 255;
+			else v = f;
 			data[idx+i] = v;
 		}
 }