Subject: Re: [linux-audio-dev] LAAGA restrictions
From: Steve Harris (S.W.Harris_AT_ecs.soton.ac.uk)
Date: Thu May 17 2001 - 20:26:27 EEST
On Thu, May 17, 2001 at 11:00:43AM -0400, Paul Davis wrote:
> Actually, its slightly weaker than that: GTK. AES doesn't care which
> language binding you use, as long as the underlying toolkit is GTK.
>
> I don't view this as acceptable. I want Muse to work in this
> framework, and I don't think that its author will be happy about
> having to rewrite it in GTK!
But muse can still be in there as an MP app. I ws thinking the restrictions
would apply only to SP apps.
> I don't think that Ardour's performance will suffer in any noticeable
> way, other than to have slightly fewer cycles available for plugins.
And less reliable under load.
> >Known nominal 0db value (e.g. 1.0f)
>
> my (admittedly weak) understanding of "dB" suggests that this makes no
> sense. you could say that 1.0f is N dBa (or is that dBFS or dBv?), but
Sorry, I didn't make that clear, I meant dBFS. i.e. 1.0f equates to a
maximum expected signal. If you were the first plugin in the chain it
would be reasonable to expect not to get signals over +-1.0, and if you
were the last you would expect a signal of +-1.1 to clip.
It is purely nominal, but thats fine.
> >Minimum sample rate (e.g. 44.1k's)
>
> Seems like quite a restriction. Why do you want this? I would prefer
> to have plugins just discover the engine sample rate, and decide that
> they can't be instantiated, or something like that, if they're really
> that fussy about SR.
Thats fine too, as long as they have a way of refusing. I suppose they are
capable of alerting the user, which isn't really possible in LADSPA.
> >Guaranteed 2^n block size
>
> we can't guarantee that. if there ends up being a reason for the
> engine to have "events", it may have to subdivide a 2^n block.
Wouldn't it be better to do events by some other means, timestamping for
example?
> >A way for apps to indicate thier current latency would be good too.
>
> This concept doesn't really exist. In Ardour, for example, is the
> latency the figure for a particular signal routing? That could be very
> different depending on what LADSPA plugins and physical i/o
> send/return combinations are in effect.
Fair enough, I suppose that will be true of most apps. I'm still thinking
about simple plugins I think.
- Steve
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