Subject: Re: [linux-audio-dev] Additional LADSPA hints
From: Mike Rawes (mike_rawes_AT_yahoo.co.uk)
Date: Thu Jan 16 2003 - 19:17:08 EET
--- Jack O'Quin <joq_AT_io.com> wrote: > Steve Harris
<S.W.Harris_AT_ecs.soton.ac.uk> writes:
>
> > > On Wed, 15 Jan 2003 18:13:35 +0000
> > > Steve Harris <S.W.Harris_AT_ecs.soton.ac.uk> wrote:
> > >
> > > > AUDIO_RATE_CONTROL. Hints than an audio control should/could be
> controlled
> > > > by a high time res. slider or control data, but shouldn't be connected
> to
> > > > the next audio signal by default. I can't think of any simple examples
> off
> > > > hand, but combined with MOMENTARY it could be used for sample accurate
> > > > tempo tapping.
> > > >
> > > > My comments: I really like MOMENTARY and RANDOMISABLE.
> AUDIO_RATE_CONTROL
> > > > could be useful, but might be painful for hosts to implement. I dont
> have
> > > > any particular use for it right now.
>
> > On Thu, Jan 16, 2003 at 02:38:53PM +0200, janne halttunen wrote:
> > > Not to mention that AUDIO_RATE_CONTROL would completely useless in JACK?
>
> > > You'd have a buffer-full of samples and apply frequency shift to them,
> > > which would change the length of that buffer, which you couldn't give to
> > > JACK unless you do some rebuffering.
> >
> > No, I dont think so. An audio rate control is just one that has a value
> > per sample, instead of a value per block. Its usful for things like FM
> > frequency which can be changed very quickly. Hey, I just thought of a use
> > for it ;)
More uses:
* Vibrato/Tremolo (sounds better with continuous control)
* Fast transients (percussion synthesis)
* Smoother response to erratic input (smoothing the output from a gui
widget makes for a nicer 'feel')
In short, I support the addition of this hint to LADSPA :)
>
> There's a syntactic ambiguity in the name AUDIO_RATE_CONTROL. Steve
> uses it to describe a Controller which runs at Audio Rate (i.e. sample
> clock speed). But, Janne understood it to mean a Controller *of* the
> Audio Rate, which is not allowed. Maybe a different name
> (CONTINUOUS_CONTROLLER?) would be clearer.
Seconded. I think including 'AUDIO' in the hint would confuse matters. A short
comment in ladspa.h could specifiy that 'continuous' means 'at audio rate'.
Mike
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