diff --git a/src/utils/filters_utils.c b/src/utils/filters_utils.c
index 39b81281..48b1606f 100644
--- a/src/utils/filters_utils.c
+++ b/src/utils/filters_utils.c
@@ -33,8 +33,9 @@ static WEBP_INLINE int GradientPredictor(uint8_t a, uint8_t b, uint8_t c) {
   return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255;  // clip to 8bit
 }
 
-WEBP_FILTER_TYPE WebPEstimateBestFilter(const uint8_t* data, int width,
-                                        int height, int stride) {
+WEBP_FILTER_TYPE WebPEstimateBestFilter(
+    const uint8_t* WEBP_COUNTED_BY((size_t)width* height) data, int width,
+    int height, int stride) {
   int i, j;
   int bins[WEBP_FILTER_LAST][SMAX];
   WEBP_UNSAFE_MEMSET(bins, 0, sizeof(bins));
diff --git a/src/utils/filters_utils.h b/src/utils/filters_utils.h
index c1e545ae..d852c23c 100644
--- a/src/utils/filters_utils.h
+++ b/src/utils/filters_utils.h
@@ -25,8 +25,9 @@ extern "C" {
 #endif
 
 // Fast estimate of a potentially good filter.
-WEBP_FILTER_TYPE WebPEstimateBestFilter(const uint8_t* data, int width,
-                                        int height, int stride);
+WEBP_FILTER_TYPE WebPEstimateBestFilter(
+    const uint8_t* WEBP_COUNTED_BY((size_t)width* height) data, int width,
+    int height, int stride);
 
 #ifdef __cplusplus
 }  // extern "C"