[gmpi] Re: Reqs 3.9. Time - opening arguments.1

  • From: "Jeff McClintock" <jeffmcc@xxxxxxxxxx>
  • To: <gmpi@xxxxxxxxxxxxx>
  • Date: Fri, 6 Feb 2004 09:56:11 +1300

> >I can grok that.  Finally, I grok that.  BuT now I don't see why you need
> >UST per event, if it is linear, it has a defined relationship to the
> >time.
> >
> >UST(sample) = UST_base_offset + sample * UST_per_sample
> you can't know UST_per_sample. its not guaranteed constant. both the
> UST timeflow and the audio sample clock have drift.

That drift is fairly minimal.  My soundcard sample clock drifts at a rate of
1ms every 4 seconds.  I recalculate 'UST_base_offset' 4 times per second,
which is plenty often enough.

If i was super-paranoid, I'd calculate the average drift and extrapolate a
very precise 'UST_base_offset' at any given sampleclock.  However Window's
multimedia timing isn't accurate enough to make it worthwhile.

Don't burden every event with a UST time, the host can provide it (given the
sample time).

Best Regards,

Generalized Music Plugin Interface (GMPI) public discussion list
Participation in this list is contingent upon your abiding by the
following rules:  Please stay on topic.  You are responsible for your own
words.  Please respect your fellow subscribers.  Please do not
redistribute anyone else's words without their permission.

Archive: //www.freelists.org/archives/gmpi
Email gmpi-request@xxxxxxxxxxxxx w/ subject "unsubscribe" to unsubscribe

Other related posts: