Original commit message from CVS:

* gst/base/gstbasesrc.c: (gst_base_src_query):
use conversions
* gst/gstutils.c: (gst_guint64_to_gdouble),
(gst_gdouble_to_guint64), (gst_util_uint64_scale):
* gst/gstutils.h:
externalize, basesrc uses it
obviously the implementation needs testing