[fpc-pascal] Re: Linux sound (especially MIDI) programming: ALSA?
Mark Morgan Lloyd
markMLl.fpc-pascal at telemetry.co.uk
Tue May 15 13:15:27 CEST 2012
Mark Morgan Lloyd wrote:
> leledumbo wrote:
> Thanks for those. Also
> http://perso.wanadoo.es/plcl/alsapas/alsapas-en.html so as I thought
> there appears to be (at least) two sets of ALSA bindings: fpalsa and
> Noted HuMuS, but that appears to be for PortAudio. However using that as
> a seed I get to http://breakoutbox.de/pascal/pascal.html#PortAudio which
> claims to include PortMidi support- this is supposedly cross-platform
> but requires an additional library which might not be available on all
> distreaux. Also MIDI is very much the "poor cousin" and operating
> support is patchy, so since I've got ALSA working I'm reluctant to risk
> breaking anything.
> Since running on anything other than Linux is not a significant
> priority, I think I'll probably start off with by doing a comparison of
> fpalsa and alsapas, and writing code that will support either if
> possible. If I could also code to support PortMidi that would be a
> bonus, but by no means essential: I'm trying to knock together a MIDI
> transposer for my own use, and testbed some techniques for another project.
To wrap this up, alsapas is a translation of the ALSA headers etc. as of
v0.9.7, and fpalsa is similar but corresponds to the slightly later
v1.0.24. They have a slightly different style in that alsapas uses
variable parameters while fpalsa uses pointers to be a bit closer to the
original (and possibly to allow null parameters); alsapas is attractive
in that it's got useful examples.
As far as MIDI is concerned, alsapas still works but there's a handful
of parameters named "out" that are no longer compatible with FPC, I've
followed the author's convention and renamed those to _out; basic
operation appears OK on Debian "Squeeze" x86 with a 3.2 kernel.
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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