v4l2src: add a comment about a "hidden" assumption on rank values

https://bugzilla.gnome.org/show_bug.cgi?id=665387

diff --git a/sys/v4l2/gstv4l2object.c b/sys/v4l2/gstv4l2object.c
index 76ac677823cb9c92774275de72d0504d2eaad5d5..f191bc9a4549f558bb8c7efc7ebba5b7e14a49b4 100644 (file)
--- a/sys/v4l2/gstv4l2object.c
+++ b/sys/v4l2/gstv4l2object.c
@@ -893,6 +893,8 @@ gst_v4l2_object_get_format_from_fourcc (GstV4l2Object * v4l2object,
 
 
 /* complete made up ranking, the values themselves are meaningless */
+/* These ranks MUST be X such that X<<15 fits on a signed int - see
+   the comment at the end of gst_v4l2_object_format_get_rank. */
 #define YUV_BASE_RANK     1000
 #define JPEG_BASE_RANK     500
 #define DV_BASE_RANK       200