Subject: Re: [linux-audio-dev] API for Input / Output plugins
From: J_Zar (romaninz_AT_aruba.it)
Date: Thu May 13 2004 - 23:51:53 EEST
Alle 00:01, mercoledì 12 maggio 2004, Paul Davis ha scritto:
> > Besides I see around the LADSPA API for sound processing but nothing si
> >milar
> >for input / output.
>
> there are good reasons for that.
>
> > However, what about writing an advanced API for I/O plugins, completely
> >detached from other programs ( as Xmms ), potentially multiplatform, to
> > suit the needs of the big part of audio programs? I mean, a plugin
> > written for a
>
> there are fundamentally different approaches to handling i/o when it
> involves hardware. one of them is based on the traditional unix
> read/write model, the other is based on a callback/interrupt
> model. its not easy to reconcile these models. in fact, its basically
> impossible without adding lots of buffering and thus killing latency
> performance.
>
This is a good reason... agree
> portaudio *does* support ALSA, but only in CVS. thats as close as you
> will get to a "standard". ALSA and OSS both provide (or maybe i should
> say, tend to result in the use of) the read/write model. JACK,
> CoreAudio, ASIO/EASI/GDIF and PortAudio all require the
> callback/interrupt model (more or less, anyway).
>
I found the PortAudio support for Jack too... nice! I don't know this. This is
enough to judge stupid my idea! Thank you Paul.
> choosing between these two models makes a phenomenal difference to the
> design of your overall application. its not a choice to be taken
> lightly, and you can't move back and forth between the two models with
> ease.
>
> now, take a look at the list of apps that support JACK
> (http://jackit.sf.net/apps). then consider that JACK supports ALSA and
> OSS on Linux and CoreAudio on OS X, and ask yourself "do you feel
> lucky?" :)))
>
Yes I do ;-D
> >certain API ( i.e. ALSA, OSS, Jack, OsX etc... ) will be usable for all
> > other applications with all advantages of a plugin architecture and
> > standard code... Input plugins are important too: I see lot of apps
> > rewriting continuosly Ogg, Mp3 or Wav support in any kind of flavour, but
> > not always reusable code. About writing it once for all?
>
> for audio file I/O, libsndfile takes care of that rather nicely, thank
> you, and there are an ever growing number of programs that use it. its
> even gaining popularity in the non-linux world. its hard to see any
> reason to even think about a different API.
>
> --p
Well... To be onestly sndfile does not support Ogg and will never support Mp3.
These two formats are maybe the 40/50% of the whole audio stuff. Ok but Mad
and Vorbifile are enough.
Finally I agree: no reason for I/O API.
Thank you for the time lost for me!
--J_Zar Gianluca Romanin ---------------- see you at OpenJay.Org
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