diff --git a/libavcodec/sonic.c b/libavcodec/sonic.c
index ad1552a434..7e4427f748 100644
--- a/libavcodec/sonic.c
+++ b/libavcodec/sonic.c
@@ -475,13 +475,13 @@ static int predictor_calc_error(int *k, int *state, int order, int error)
     for (i = order-2; i >= 0; i--, k_ptr--, state_ptr--)
     {
         int k_value = *k_ptr, state_value = *state_ptr;
-        x -= shift_down(k_value * (unsigned)state_value, LATTICE_SHIFT);
+        x -= (unsigned)shift_down(k_value * (unsigned)state_value, LATTICE_SHIFT);
         state_ptr[1] = state_value + shift_down(k_value * (unsigned)x, LATTICE_SHIFT);
     }
 #else
     for (i = order-2; i >= 0; i--)
     {
-        x -= shift_down(k[i] * state[i], LATTICE_SHIFT);
+        x -= (unsigned)shift_down(k[i] * state[i], LATTICE_SHIFT);
         state[i+1] = state[i] + shift_down(k[i] * x, LATTICE_SHIFT);
     }
 #endif