diff --git a/libavcodec/sonic.c b/libavcodec/sonic.c
index 8662737837..ea107d4ff6 100644
--- a/libavcodec/sonic.c
+++ b/libavcodec/sonic.c
@@ -467,7 +467,7 @@ static void predictor_init_state(int *k, int *state, int order)
 
 static int predictor_calc_error(int *k, int *state, int order, int error)
 {
-    int i, x = error - shift_down(k[order-1] *  (unsigned)state[order-1], LATTICE_SHIFT);
+    int i, x = error - (unsigned)shift_down(k[order-1] *  (unsigned)state[order-1], LATTICE_SHIFT);
 
 #if 1
     int *k_ptr = &(k[order-2]),
@@ -1009,7 +1009,7 @@ static int sonic_decode_frame(AVCodecContext *avctx,
     if (s->lossless)
         quant = 1;
     else
-        quant = get_symbol(&c, state, 0) * SAMPLE_FACTOR;
+        quant = get_symbol(&c, state, 0) * (unsigned)SAMPLE_FACTOR;
 
 //    av_log(NULL, AV_LOG_INFO, "quant: %d\n", quant);