Re: [fluid-dev] Jack Driver for Fluidsynth Windows Build

[David Henningsson]

Hi Graham,

I don't want to push the problem back and forward, but in this case I 
think it's reasonable to say that:

1) We need to be told by the Jack devs about recommended way to link to 
the jack headers. Does that means dynamic linking? On windows only or on 
all platforms? Will that still work with e g Jack 1? Anyway, if we 
conclude dynamic linking is the way forward, it is reasonable to think 
that there should be a version of JackWeakAPI.cpp that is in C and not 
C++ (just like the rest of FS). I don't exactly know how difficult it 
would be to bring C++ code into FS on all platforms, but it would 
probably be more difficult than rewriting JackWeakAPI.cpp in pure C.

2) If Jack has an ASIO backend, that's great news! However, looking at
http://trac.jackaudio.org/browser/jack2/trunk/jackmp/windows/JackRouter/JackRouter.h
it seems to be declared under GPLv2+. I don't see how the end result 
could be legally distributed in binary form, when the ASIO headers 
cannot be freely distributed.

// David

On 2011-04-17 17:56, Graham Goode wrote:
> Hi Guys,
>
> As a user and tester of fluidsynth with Qsynth and jOrgan, I have been
> wanting low latency connections rather than the default 'dsound'
> driver for a while. To this end, and with some help, I finally got a
> PortAudio build done and working, and so I have WDMKS/WASAPI and ASIO
> available now. The problem with WDMKS and ASIO is that only a single
> instance of fluidsynth can be run.
>
> So I communicated with some of the PortAudio guys and with this
> mailing list about multi-instance PortAudio, and the end result of
> that communication is that the understanding that the 'single
> instance' part of the WDMKS and the ASIO is with their respective
> APIs.
>
> So, I approached Stéphane to see if the ASIO branch could be modified
> to allow multiple connections to JackRouter (the Jack ASIO driver).
> While this is programatically possible, the consensus was that it
> would be much better to use the Jack driver natively in fluidsynth.
> According to Stéphane one can use "weak linking" to solve the 'Is Jack
> present, and if so is the version compatible' problem. On Windows the
> simplest is to compile the following file:
>
> http://trac.jackaudio.org/browser/jack2/trunk/jackmp/common/JackWeakAPI.cpp
>
> Would it be possible for those more experienced than I am to look at
> this idea and see if this is the valuable way forward for windows
> users that I think it could be?
>
> Thanks, and kind regards,
> GrahamG
>
> On 4/16/11, Stéphane Letz<address@hidden>  wrote:
> > Le 16 avr. 2011 à 10:51, Graham Goode a écrit :
> >
> > > Hi Stéphane,
> > >
> > > I see from the pa_asio.cpp file that you are the author of the ASIO
> > > driver for PortAudio. Thanks for all your work to get ASIO working
> > > with PortAudio. With Rob's help I have been able to build the
> > > WDMKS\WaveRT branch with the WDMKS and ASIO drivers for use with
> > > fluidsynth in jOrgan. The PortAudio ASIO driver sees JackRouter and
> > > connects very nicely, but there is one issue that I would like to
> > > raise to see if there is a way around it.
> > >
> > > When using the PortAudio ASIO driver with fluidsynth, only one
> > > instance of fluidsynth will run.
> >
> >
> > fluidsynth has a JACK driver right? (I know the answer is yes... ((-:)
> >
> > So would be even better to ask fluidsynth developers to compile JACK support
> > for windows , using the "weak linking" method I described for LinuxSampler.
> >
> > Stephane
>
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