Re: Audio Unit synth how-to
Re: Audio Unit synth how-to
- Subject: Re: Audio Unit synth how-to
- From: h <email@hidden>
- Date: Fri, 6 May 2005 16:02:14 -0700 (PDT)
- Comment: DomainKeys? See http://antispam.yahoo.com/domainkeys
Thanks. What about latency?
Suppose I have a 1024-sample buffer that I am rendering, and a note on
event happens when I am at sample 512. Do I have to wait until the end
of rendering 1024 samples before I am sent the note-on event?
(I have noticed the 1024 sample buffer size when using Logic Express as
a host).
Many thanks,
Hamish
--- Chris Rogers <email@hidden> wrote:
> Have a look at the inStartFrame argument to the HandleNoteOn()
> method.
> This gives a sample-frame offset where the note should start during
> the
> current render buffer. It is normal and correct that you should see
> HandleNoteOn() and Render() being called in the same thread.
> At the start of every render cycle, notes and parameter changes are
> scheduled,
> then your Render() method is called to synthesize the results for
> that time slice....
>
> Chris Rogers
> Core Audio
> Apple Computer
>
>
>
> On May 6, 2005, at 3:18 PM, h wrote:
>
> > I am writing an Audio Unit synth based on the MusicDeviceBase class
> in
> > the CoreAudio examples.
> >
> > What I am finding is that HandleNoteOn() and Render() are being
> called
> > on the same thread (checked using pthread_self()). Obviously, this
> > causes note on/off events to be made only between calls to
> Render().
> > This allows accuracy of only +/- 1024 or 512 samples, depending on
> the
> > number of frames requested.
> >
> > How do I make the calls to HandleNoteOn/HandleNoteOff come in on
> the
> > appropriate thread, and how do I make sure that the notes are
> turned
> > on/off in a sample-accurate matter (presumably I need to check
> before
> > processing each sample in Render())? Is it something to do with the
> > inStartFrame parameter to HandleNoteOn/Off?
> >
> > Is there an example of a sample-accurate midi synth audio unit?
> >
> > Thanks,
> > Hamish
> >
> >
> >
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