diff --git a/libavcodec/pcm.c b/libavcodec/pcm.c
index e2a733495e..9100646179 100644
--- a/libavcodec/pcm.c
+++ b/libavcodec/pcm.c
@@ -71,7 +71,7 @@ static av_cold int pcm_encode_close(AVCodecContext *avctx)
  * @param offset Sample value offset
  */
 #define ENCODE(type, endian, src, dst, n, shift, offset) \
-    samples_##type = (type*)src; \
+    samples_##type = (const type*) src; \
     for(;n>0;n--) { \
         register type v = (*samples_##type++ >> shift) + offset; \
         bytestream_put_##endian(&dst, v); \