diff --git a/libavcodec/aacenc.c b/libavcodec/aacenc.c
index 127ad4a810..2a3fc6e1c4 100644
--- a/libavcodec/aacenc.c
+++ b/libavcodec/aacenc.c
@@ -154,7 +154,7 @@ static void apply_window_and_mdct(AACEncContext *s, SingleChannelElement *sce,
                                   float *audio)
 {
     int i;
-    float *output = sce->ret_buf;
+    const float *output = sce->ret_buf;
 
     apply_window[sce->ics.window_sequence[0]](s->fdsp, sce, audio);