diff --git a/libavcodec/nellymoserdec.c b/libavcodec/nellymoserdec.c
index 0f2a826ccf..204910d2c1 100644
--- a/libavcodec/nellymoserdec.c
+++ b/libavcodec/nellymoserdec.c
@@ -118,15 +118,13 @@ static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *
 
     bot = 0;
     top = NELLY_BUF_LEN-1;
-    top2 = 2*NELLY_BUF_LEN-1;
 
     while (bot < NELLY_BUF_LEN/2) {
         audio[bot] =  (- a_in[bot]*sine_window[bot]-state[bot]*sine_window[top])/s->scale_bias + s->add_bias;
-        audio[top] =  (-state[bot]*sine_window[bot]+ a_in[bot]*sine_window[top])/s->scale_bias + s->add_bias;
-        state[bot] =  a_in[top2];
+        audio[top] =  (-state[bot]*sine_window[bot]- a_in[top]*sine_window[top])/s->scale_bias + s->add_bias;
+        state[bot] = a_in[bot + NELLY_BUF_LEN];
 
         bot++;
-        top2--;
         top--;
     }
 }