Subject: Re: [linux-audio-dev] matrix model vs. memory
From: Abramo Bagnara (abramo_AT_alsa-project.org)
Date: Sun May 20 2001 - 09:48:42 EEST
Paul Davis wrote:
>
> This is very relevant to Abramo's reply too.
>
> >I guess I am confused - are you referring to moving data between inputs
> >and outputs in a single plugin or between ports on two different plugins?
> >If the latter, then data is not really moved, right? The output of one
> >plugin _is_ the input of another, so when would all of this happen?
>
> well, if you require buffer sharing, then its impossible to have a
> multi-input port.
Why? My model supports it.
> such a port type is important for implementing busses, since
> otherwise, you have to have an input port for every object that wants
> to connect to it. its very important to me to be able to implement a
> "bus" concept easily; an N-channel mixer with a single output port is
> a much less efficient way of implementing this.
It's not parallelizable on SMP (because lack of atomic float add)
without to do some tricks, but that apart I don't see why it's less
efficient.
> moreover, if you require buffer sharing, you also require that the
> effective signal level for each of a series of connected input ports
> be controlled on a per-port basis, since they will all get the same
> data (from the output buffer).
>
> both of these seem suboptimal to me. as i said, there is already an
> implicit matrix of port connections; exposing it and attaching a gain
> at each node of the matrix seems like a really cool idea to me.
As an *option*, otherwise you limit efficiency also when this is not
needed. This would be a symptom of a bad design.
-- Abramo Bagnara mailto:abramo_AT_alsa-project.orgOpera Unica Phone: +39.546.656023 Via Emilia Interna, 140 48014 Castel Bolognese (RA) - Italy
ALSA project http://www.alsa-project.org It sounds good!
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