diff --git a/libavcodec/tta.c b/libavcodec/tta.c
index 1ab207961e..f08b12d90b 100644
--- a/libavcodec/tta.c
+++ b/libavcodec/tta.c
@@ -287,7 +287,7 @@ static int tta_decode_init(AVCodecContext * avctx)
 
 static int tta_decode_frame(AVCodecContext *avctx,
         void *data, int *data_size,
-        uint8_t *buf, int buf_size)
+        const uint8_t *buf, int buf_size)
 {
     TTAContext *s = avctx->priv_data;
     int i;