diff --git a/alg.c b/alg.c
index 93c260f..343ff47 100644
--- a/alg.c
+++ b/alg.c
@@ -534,7 +534,7 @@ static int alg_labeling(struct context *cnt)
     imgs->labels_above = 0;
 
     /* Init: 0 means no label set / not checked. */
-    memset(labels, 0, width * height * sizeof(labels));
+    memset(labels, 0, width * height * sizeof(*labels));
     pixelpos = 0;
 
     for (iy = 0; iy < height - 1; iy++) {
@@ -1363,6 +1363,6 @@ void alg_update_reference_frame(struct context *cnt, int action)
         /* Copy fresh image */
         memcpy(cnt->imgs.ref, cnt->imgs.image_virgin, cnt->imgs.size);
         /* Reset static objects */
-        memset(cnt->imgs.ref_dyn, 0, cnt->imgs.motionsize * sizeof(cnt->imgs.ref_dyn)); 
+        memset(cnt->imgs.ref_dyn, 0, cnt->imgs.motionsize * sizeof(*cnt->imgs.ref_dyn));
     }
 }
diff --git a/motion.c b/motion.c
index 5666770..dd4ac2a 100644
--- a/motion.c
+++ b/motion.c
@@ -723,13 +723,13 @@ static int motion_init(struct context *cnt)
     memset(cnt->imgs.out, 0, cnt->imgs.size);
 
     /* contains the moving objects of ref. frame */
-    cnt->imgs.ref_dyn = mymalloc(cnt->imgs.motionsize * sizeof(cnt->imgs.ref_dyn));
+    cnt->imgs.ref_dyn = mymalloc(cnt->imgs.motionsize * sizeof(*cnt->imgs.ref_dyn));
     cnt->imgs.image_virgin = mymalloc(cnt->imgs.size);
     cnt->imgs.smartmask = mymalloc(cnt->imgs.motionsize);
     cnt->imgs.smartmask_final = mymalloc(cnt->imgs.motionsize);
-    cnt->imgs.smartmask_buffer = mymalloc(cnt->imgs.motionsize * sizeof(cnt->imgs.smartmask_buffer));
-    cnt->imgs.labels = mymalloc(cnt->imgs.motionsize * sizeof(cnt->imgs.labels));
-    cnt->imgs.labelsize = mymalloc((cnt->imgs.motionsize/2+1) * sizeof(cnt->imgs.labelsize));
+    cnt->imgs.smartmask_buffer = mymalloc(cnt->imgs.motionsize * sizeof(*cnt->imgs.smartmask_buffer));
+    cnt->imgs.labels = mymalloc(cnt->imgs.motionsize * sizeof(*cnt->imgs.labels));
+    cnt->imgs.labelsize = mymalloc((cnt->imgs.motionsize/2+1) * sizeof(*cnt->imgs.labelsize));
 
     /* Set output picture type */
     if (!strcmp(cnt->conf.picture_type, "ppm"))
@@ -917,7 +917,7 @@ static int motion_init(struct context *cnt)
     /* Always initialize smart_mask - someone could turn it on later... */
     memset(cnt->imgs.smartmask, 0, cnt->imgs.motionsize);
     memset(cnt->imgs.smartmask_final, 255, cnt->imgs.motionsize);
-    memset(cnt->imgs.smartmask_buffer, 0, cnt->imgs.motionsize*sizeof(cnt->imgs.smartmask_buffer));
+    memset(cnt->imgs.smartmask_buffer, 0, cnt->imgs.motionsize * sizeof(*cnt->imgs.smartmask_buffer));
 
     /* Set noise level */
     cnt->noise = cnt->conf.noise;