diff --git a/src/dsp/lossless_enc.c b/src/dsp/lossless_enc.c
index b0346cab..0f7fdebb 100644
--- a/src/dsp/lossless_enc.c
+++ b/src/dsp/lossless_enc.c
@@ -520,8 +520,8 @@ void VP8LTransformColor_C(const VP8LMultipliers* const m, uint32_t* data,
   int i;
   for (i = 0; i < num_pixels; ++i) {
     const uint32_t argb = data[i];
-    const uint32_t green = argb >> 8;
-    const uint32_t red = argb >> 16;
+    const int8_t green = (argb >>  8) & 0xff;
+    const int8_t red   = (argb >> 16) & 0xff;
     int new_red = red & 0xff;
     int new_blue = argb & 0xff;
     new_red -= ColorTransformDelta(m->green_to_red_, green);
@@ -535,7 +535,7 @@ void VP8LTransformColor_C(const VP8LMultipliers* const m, uint32_t* data,
 
 static WEBP_INLINE uint8_t TransformColorRed(uint8_t green_to_red,
                                              uint32_t argb) {
-  const uint32_t green = argb >> 8;
+  const int8_t green = (argb >> 8) & 0xff;
   int new_red = argb >> 16;
   new_red -= ColorTransformDelta(green_to_red, green);
   return (new_red & 0xff);
@@ -544,8 +544,8 @@ static WEBP_INLINE uint8_t TransformColorRed(uint8_t green_to_red,
 static WEBP_INLINE uint8_t TransformColorBlue(uint8_t green_to_blue,
                                               uint8_t red_to_blue,
                                               uint32_t argb) {
-  const uint32_t green = argb >> 8;
-  const uint32_t red = argb >> 16;
+  const int8_t green = (argb >>  8) & 0xff;
+  const int8_t red   = (argb >> 16) & 0xff;
   uint8_t new_blue = argb & 0xff;
   new_blue -= ColorTransformDelta(green_to_blue, green);
   new_blue -= ColorTransformDelta(red_to_blue, red);
@@ -558,7 +558,7 @@ void VP8LCollectColorRedTransforms_C(const uint32_t* argb, int stride,
   while (tile_height-- > 0) {
     int x;
     for (x = 0; x < tile_width; ++x) {
-      ++histo[TransformColorRed(green_to_red, argb[x])];
+      ++histo[TransformColorRed((uint8_t)green_to_red, argb[x])];
     }
     argb += stride;
   }
@@ -571,7 +571,8 @@ void VP8LCollectColorBlueTransforms_C(const uint32_t* argb, int stride,
   while (tile_height-- > 0) {
     int x;
     for (x = 0; x < tile_width; ++x) {
-      ++histo[TransformColorBlue(green_to_blue, red_to_blue, argb[x])];
+      ++histo[TransformColorBlue((uint8_t)green_to_blue, (uint8_t)red_to_blue,
+                                 argb[x])];
     }
     argb += stride;
   }