diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index 52d0d44cc2..de79a89c4e 100644
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -1213,10 +1213,10 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
 
                     for (count2=0; count2<28; count2++) {
                         if (count2 & 1)
-                            next_sample = sign_extend(byte,    4) << shift;
+                            next_sample = (unsigned)sign_extend(byte,    4) << shift;
                         else {
                             byte = bytestream2_get_byte(&gb);
-                            next_sample = sign_extend(byte >> 4, 4) << shift;
+                            next_sample = (unsigned)sign_extend(byte >> 4, 4) << shift;
                         }
 
                         next_sample += (current_sample  * coeff1) +