[linux-audio-dev] Grabbing sound using Roland Edirol FA-101

[Jonathan Woithe]

Helge Fredriksen wrote:
> 
> Did any of you guys ever tried to use the OpenAL API interface towards a
> Firewire sound device like FA-101? I see that it appears on your lists as a
> device that has drivers on Linux.

AFAIK OpenAL doesn't talk to hardware directly - it provides an API for
programs to use but sends data to the soundcard via the operating system's
native sound system.  Therefore the devices supported by OpenAL are the
devices supported by the underlying operating system.  For many sound cards
under Linux, that native sound system is ALSA (http://www.alsa-project.org).
OSS was the previous default native sound system under Linux and is still in
use by numerous programs.

The FA-101 is (as you'd know) a firewire interface.  Support for firewire
interfaces is starting to gain momentum now but for various technical
reasons this is not provided by ALSA at this time.  The support effort is
the so-called Freebob project (http://freebob.sourceforge.net) in
combination with the JACK system (http://www.jackaudio.org/), a low-latency
audio API.  Only a small number of firewire audio interfaces are supported
by freebob at this time, but from what I read the FA-101 is one of them.

Getting back to your question, if OpenAL supports JACK under Linux then in
theory you could talk to an FA-101 via OpenAL.  According to the OpenAL
website it currently only supports OSS and ALSA under Linux.  Therefore at
this point in time you can't use OpenAL to send audio to an FA-1-1. 
However, unless you particularly wanted the 3D modelling features of OpenAL
you'd probably be better off using the JACK API directly.

It should be noted that a long-term goal of the freebob project is to
implement an ALSA driver for the firewire interfaces.  However, there is
still much to do before that will occur so I can't see it appearing any time
soon.  Once it did appear (and assuming OpenAL don't implement an interface
to JACK earlier) you would be able to use OpenAL with the FA-101.

Regards
  jonathan