Subject: Re: [linux-audio-dev] One API for everything (first draft)
From: Abramo Bagnara (abramo_AT_alsa-project.org)
Date: Sun May 20 2001 - 16:02:52 EEST
Paul Davis wrote:
>
> >> #define SOUNDBOX_PORT_PROPERTY_BUFFER_SHAPE /* interleaved, noninterleav
> >ed,
> >> complex */
> >>
> >> if a hardware PCM "component" exports this kind of stuff, we're in no
> >> better shape than using ALSA when it comes to abstraction.
> >
> >If I don't export it, you lose efficiency is this what you want?
>
> Yes. The only thing that might deal with hardware buffer layout is a
> plugin that interacts directly with the h/w, and it will hide the
> layout behind its own i/o ports. No other plugins ever get to write
> directly into the hardware buffer. Remember, I wrote a system which
You're a professional audio bigot ;-) soundboxes are also for hundreds
of application that have always used interleaved buffers.
Do you want *really* to have two APIs, one for professional level and
one for consumer one?
> However, even this format for a buffer is not free of the
> "run/run_adding" problem, since in some situations, the buffer is most
> efficiently used via assignment, and in others maximum efficiency
> requires "+=". Its not a trivial problem to make this a run-time
> choice, and in many cases, its almost impossible. If you only
> imagine simple LADSPA-like plugins, its a bit easier.
>
> However, since the number of ports on the kind of plugins we're trying
> to support may be very large and their interconnections very complex,
> there is no simple way to tell the plugin to use the "=" or "+="
> method; indeed, there may be no simple way for the plugin to select
> these methods internally.
>
> This is still an unsolved problem, as far as i can tell.
In my model the choice is left to soundbox client/user and it's not
*dynamic* (it's a property and not a control). Only relaxing the
soundbox it's modifiable.
-- 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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