org: Relative timer

 
 8.6 Taking notes with a relative timer
 ======================================
 
 When taking notes during, for example, a meeting or a video viewing, it
 can be useful to have access to times relative to a starting time.  Org
 provides such a relative timer and make it easy to create timed notes.
 
 ‘C-c C-x .     (org-timer)’
      Insert a relative time into the buffer.  The first time you use
      this, the timer will be started.  When called with a prefix
      argument, the timer is restarted.
 ‘C-c C-x -     (org-timer-item)’
      Insert a description list item with the current relative time.
      With a prefix argument, first reset the timer to 0.
 ‘M-<RET>     (org-insert-heading)’
      Once the timer list is started, you can also use ‘M-<RET>’ to
      insert new timer items.
 ‘C-c C-x ,’
      Pause the timer, or continue it if it is already paused
      (‘org-timer-pause-or-continue’).
 ‘C-u C-c C-x ,’
      Stop the timer.  After this, you can only start a new timer, not
      continue the old one.  This command also removes the timer from the
      mode line.
 ‘C-c C-x 0     (org-timer-start)’
      Reset the timer without inserting anything into the buffer.  By
      default, the timer is reset to 0.  When called with a ‘C-u’ prefix,
      reset the timer to specific starting offset.  The user is prompted
      for the offset, with a default taken from a timer string at point,
      if any, So this can be used to restart taking notes after a break
      in the process.  When called with a double prefix argument ‘C-u
      C-u’, change all timer strings in the active region by a certain
      amount.  This can be used to fix timer strings if the timer was not
      started at exactly the right moment.