diff --git a/libavcodec/alacenc.c b/libavcodec/alacenc.c
index 85adb40a7a..afa1ac68e0 100644
--- a/libavcodec/alacenc.c
+++ b/libavcodec/alacenc.c
@@ -330,7 +330,8 @@ static void write_compressed_frame(AlacEncodeContext *s)
     int i, j;
 
     /* only simple mid/side decorrelation supported as of now */
-    alac_stereo_decorrelation(s);
+    if(s->avctx->channels == 2)
+        alac_stereo_decorrelation(s);
     put_bits(&s->pbctx, 8, s->interlacing_shift);
     put_bits(&s->pbctx, 8, s->interlacing_leftweight);