1 files changed, 3 insertions, 0 deletions
diff --git a/video/out/vo.h b/video/out/vo.h
index 851dd16159..17cb692356 100644
--- a/video/out/vo.h
+++ b/video/out/vo.h
@@ -354,6 +354,9 @@ struct vo_driver {
 
     /* Render the given frame. Note that this is also called when repeating
      * or redrawing frames.
+     *
+     * frame is freed by the caller, but the callee can still modify the
+     * contained data and references.
      */
     void (*draw_frame)(struct vo *vo, struct vo_frame *frame);