Subject: Re: [linux-audio-dev] more on LADSPA
From: Paul Barton-Davis (pbd_AT_Op.Net)
Date: Wed Nov 22 2000 - 00:22:35 EET
>This is why I propose not to use LADSPA when implementing
>"applications-as-plugins". With all the bells and whistles an app
>such your HDR requires, LADSPA will loose its simplictiy failing to
>deliver its initial goal.
well, perhaps. but again, you could do something like this within a
VST-like framework, where the host provided certain callbacks for the
plugin to use during instantiate(), activate(), and so on.
>As for the samplerate issues, we would need some kind of arbitration
>between plugs and the host, but some problems may arise if you run
>several plugs (like your HRD) which are rate dependent.
>
>What if HDR1 works only at 48kHz and HDR2 only at 44.1kHz ?
the same as happens right now with a DAT recorded at 48kHz and a
machine that can't play back at that rate ... you're hosed.
>IMHO the samplerate should be dictated by the host, but we could
>give the plugs the possiblity to ask the host for a certain samplerate.
what you're missing is that the plugin doesn't know *what* (who?) its
asking for a sample rate. i agree that ultimately its down to a host
to control the actual audio h/w.
but that shouldn't stop the plugin from asking for the rate it needs,
because that doesn't imply it has any control over the audio h/w. in
fact, the plugin is almost certainly connected to another intermediate
layer which could, if it wanted to, do resampling.
>I understand that (assuming ardour runs as a plugin within the virtual studio
>host) you want to let the user specify the samplerate from within ardour's
> control panel and that's Ok.
not quite. its a property of any particular recording session. but its
not really much of a difference.
>But what does happen if another "application" is running at the same
>time but cannot handle the new sampling rate (perhaps due to
>algorithmic constraint s or other stuff) ?
the plugin's request is denied, and given any particular application,
the dialog you propose might be created.
--p
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