diff --git a/audio/chmap.c b/audio/chmap.c
index a67c4e1c70..9a18512e21 100644
--- a/audio/chmap.c
+++ b/audio/chmap.c
@@ -485,5 +485,5 @@ void mp_chmap_print_help(struct mp_log *log)
                  std_layout_names[n][0], std_layout_names[n][1]);
     }
     for (int n = 0; n < MP_NUM_CHANNELS; n++)
-        mp_info(log, "    unknown%d\n", n);
+        mp_info(log, "    unknown%d\n", n + 1);
 }