I have looked at the list archives, and discovered some previous postings on
a similar topic, about "elapsed time."  Perhaps I can be more specific.

On Mon, Nov 24, 2008 at 12:01 PM, Alan E. Davis <lngndvs@gmail.com> wrote:

> I have been taking notes on videos, and need a relative clock function,
> starting when I start the film.


A post by Adam Speirs made a useful suggestion in response to a question by
Alan Dove:

    http://lists.gnu.org/archive/html/emacs-orgmode/2007-07/msg00338.html

In particular, he posted three functions.  I have gotten them to work, they
are simple.  I am uncertain how they interact with Org Mode, whether they
work in a harmonious fashion with the clocking code in org mode.  I didn't
figure out how to turn off the clock!   So I rebooted when I needed to
restart.  I could edit his functions and insert exactly what I need.

I liked them because they don't require me to diddle around with properties
and drawers, with which I am yet somewhat uncomfortable.

A further suggestion is born or my initial experiment with his function: I
started the clock a bit too late, so all the timestamps are off by about
30-40 seconds.  Is it (at least in theory) possible to adjust all time
stamps in a subtree by the same amount?  That would enable me to correct all
of my notes in one fell stroke.

Thank you.

Alan



-- 
Alan Davis

"It's never a matter of liking or disliking ..."
      ---Santa Ynez Chumash Medicine Man