diff --git a/doc/examples/filtering_audio.c b/doc/examples/filtering_audio.c
index 5802d90264..1d66ca33e3 100644
--- a/doc/examples/filtering_audio.c
+++ b/doc/examples/filtering_audio.c
@@ -220,6 +220,7 @@ int main(int argc, char **argv)
         goto end;
 
     /* read all packets */
+    packet0.data = NULL;
     packet.data = NULL;
     while (1) {
         if (!packet0.data) {