Subject: Re: [linux-audio-dev] testing the waters
From: Benno Senoner (sbenno_AT_gardena.net)
Date: Mon Jun 26 2000 - 14:41:21 EEST
Waves, welcome to the Linux world !
:-)
short summary:
Linux currently uses the OSS (open-sound-system) API
the API is quite limited since it was designed for stereo cards.
But the ALSA project ( http://www.alsa-project.org ) aims much
higher, providing a multichannel interface with direct access methods
(like ASIO does for example) , in order to achieve maximum performance.
(note that the ALSA 6.0 API has not been finalized yet )
plugin standards: an open simple API (similar to VST1.0) was developed
on this list, and the main site is here: http://www.ladspa.org
Steinberg seems interested to "port" VST2.0 on Linux too.
("port" is more a graphical issue (like porting the VST widget lib) since the
DSP part is in C/C++ , therefore fully portable
Regarding latencies in Linux , as you probably already know:
current kernels do not perform well ( up to 100ms worst case latencies),
but there is a small patch avaiable which fixes the problem, and allow you
to get as low as 2.1ms (process-to-output = eg softsynth) dopoutfree
(even when the machine is heavily loaded) on a Pentium133 !
Notice that under linux you can use a simple userspace thread, without
using complicated and crashprone kernel-level programming like you
have to do under Windows in order to achieve good latencies.
(see seer reality or gigasampler)
the tests I performed with my own testtools (which use the pentium RTDSC
instruction in order to achieve maximum timing precision) are
here: http://www.gardena.net/benno/linux/audio
There is currently a debate about the inclusion of the low latency patches
in the mainstream kernel , so that future linux desktops will deliver
outstanding performance without the need of manual patching.
One draft of the letter (which will be sent to Linus) is here, and if would be
nice if you could send your signature to Paul Barton Davis ( pbd_AT_op.net) ,
since you as a plugin developer are certainly interested in getting good
realtime response. ( a software plugin run with <3-5ms latencies performs just
as well as a dedicated hardware rack)
http://www.alsa-project.org/archive/alsa-devel/msg06087.html
I hope that other members of this list will complete the pointers/topics
I forgot to mention
BTW: check out : http://www.linuxdj.com/audio/lad , the homepage of
the linux-audio-developers group ( we and you :-) )
Benno.
On Mon, 26 Jun 2000, Gil Wasserman wrote:
>
> Hello all,
>
> Some of you might have heard of us. Waves has been into the audio professional market for a long time now, providing processing tools for the Windows and Mac environments. If you feel like checking us out, visit our web site at www.waves.com. Just to clear matters, I'm not writing to entice you to buy anything!
>
> I am writing you to get some feel for what's happening with Linux regarding audio. We're considering developing solutions for Linux and following this I'm trying to get a feel of the need and scope of the Linux audience.
>
> I'd appreciate any input you guys might have or pointers you can provide me with.
>
> Thank you in advance!
>
> Gil
>
>
> Gil Wasserman
> MaxxStream Product Director
> K.S.Waves Ltd.
> Phone: 972 3 5107667 x 132
> Mobile: 972 53 276283
> Fax: 972 3 5105881
> http://www.maxxstream.com
> http://www.waves.com
>
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