diff --git a/libavcodec/xxan.c b/libavcodec/xxan.c
index 231ed908fa..84ffdecdff 100644
--- a/libavcodec/xxan.c
+++ b/libavcodec/xxan.c
@@ -307,7 +307,7 @@ static int xan_decode_frame_type0(AVCodecContext *avctx)
         int dec_size;
 
         bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
-        dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
+        dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
         if (dec_size < 0)
             dec_size = 0;
         for (i = 0; i < dec_size; i++)