diff --git a/libavcodec/wma.c b/libavcodec/wma.c
index e257aed319..c0261b1175 100644
--- a/libavcodec/wma.c
+++ b/libavcodec/wma.c
@@ -301,14 +301,10 @@ int ff_wma_init(AVCodecContext * avctx, int flags2)
 
     /* init MDCT windows : simple sinus window */
     for(i = 0; i < s->nb_block_sizes; i++) {
-        int n, j;
-        float alpha;
+        int n;
         n = 1 << (s->frame_len_bits - i);
         window = av_malloc(sizeof(float) * n);
-        alpha = M_PI / (2.0 * n);
-        for(j=0;j<n;j++) {
-            window[j] = sin((j + 0.5) * alpha);
-        }
+        ff_sine_window_init(window, n);
         s->windows[i] = window;
     }