diff --git a/doc/examples/transcoding.c b/doc/examples/transcoding.c
index e1b3311081..e32ab20245 100644
--- a/doc/examples/transcoding.c
+++ b/doc/examples/transcoding.c
@@ -227,8 +227,8 @@ static int init_filter(FilteringContext* fctx, AVCodecContext *dec_ctx,
 {
     char args[512];
     int ret = 0;
-    AVFilter *buffersrc = NULL;
-    AVFilter *buffersink = NULL;
+    const AVFilter *buffersrc = NULL;
+    const AVFilter *buffersink = NULL;
     AVFilterContext *buffersrc_ctx = NULL;
     AVFilterContext *buffersink_ctx = NULL;
     AVFilterInOut *outputs = avfilter_inout_alloc();