[linux-audio-user] trying to get ssm's JackPlugin working

Patrick Shirkey pshirkey at boosthardware.com
Fri Nov 14 10:12:31 EST 2003

Jim Lynch wrote:
> I built jack and ssm (and rebuilt my 2.4.22 kernel with caps, lowlat, 
> preempt) and I'm having problems getting the plugin to work.
> First, there was a function pointer type mismatch in the sample
> rate change callback function, which I fixed. Now, recent cvs
> ssm builds with jack-0.80.0 (well, for me... I could send my
> patch...)
> I get the jack plugin gui rect on the canvas of ssm without
> problem, it does switch back and forth between detailed and
> simple GUI.
> When I have the jack plugin without connecting it to anything
> and not attached to the jack server, output to the oss output
> works fine, but when I tell the jack plugin to attach, I get
> a buzz sound whose pitch is the same as the rate the Process
> callback is being called; if I have a mixer before the output
> plugin, the volume of the pitch is scaled by the volume sliders.
> When I have any jack plugin input connected from any ssm plugin
> output, -and- the plugin is attached to jackd -and- the jack
> plugin's input is routed to an alsa output, I get a different-
> sounding buzz that is also the same rate as the Process callback
> invocations. This buzzing sound is -not- scaled by any volume 
> sliders in ssm.
> At the moment, I'm not sure what to do... but I'm looking into
> the possibility that the samples as represented by jack are
> not of the same data type (-and- don't get converted) as the
> samples as represented by ssm.

You may be having sample rate mismatching in the options dialog. It has 
to be the same as the sample rate you run jack at and also has to point 
ot the same device hw:1,0 etc... ATM this is not automatic.

I am using ssm here now with latest cvs and the jack plugin.So far 
everything is working to order.

My fix for the function pointer type mismatch:

Seems that changing the declaration to an unsigned int on 
JackPlugin.C:174 and JackPlugin.h:62 is the fix.

Patrick Shirkey - Boost Hardware Ltd.
Http://www.djcj.org - The Linux Audio Users guide

Being on stage with the band in front of crowds shouting, "Get off! No! 
We want normal music!", I think that was more like acting than anything 
I've ever done.

Goldie, 8 Nov, 2002
The Scotsman

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