Re: [Qtractor-devel] DSSI Plugin on audio track mono, and some other (more DSSI specific) questions

[Rui N. C. <rn...@rn...>]

On 01/07/2010 05:41 PM, Mathias Krause wrote:
> Hey Rui,
> 
> at the moment, i am writing a small DSSI plugin ... and as soon as i 
> started, i ran into some problems, where i need your help:
> 
> 1. I can start my plugin with "jack-dssi-host" without problems. It has 
> 1 MIDI and 1 Audio input. When i load the dssi plugin into qtractor on a 
> MIDI track, everything seems to work fine. But when i try to load it on 
> an audio track, qtractor exits with a segmentation fault.
> 
> Do you have any idea, that could help me? Du I need to write the plugin 
> in a stereo-version?
> 

gosh. hard to tell. a stacktrace would be welcome. take note that if the
audio track is stereo, qtractor will create 2 instances of a mono plugin
behind the scenes, one for each channel. dunno if that makes any
difference, but a stereo version would be nice to consider, just in case ;)


> 2. The plugin also needs a GUI i've written in QT. This works fine, and 
> qtractor does start the GUI. But the DSSI ports which are set by 
> qtractor are not send to the GUI? Is there a special mechanism to load 
> all the data for the GUI on startup? I think, the host (qtractor) calls 
> something like an update-method?
> 

as a dssi host, qtractor will send a "control" message (via osc) to
notify the gui that it needs to update its state.

on its turn, the gui should send a similar but not in reply "control"
method that the host (ie. qtractor) will listen and effectively set the
plugin instance port value.

do not try to write/read from any port directly. that's not the way it's
supposed to work from the dssi plugin specification. afaict

> 
> 3. My plugin has some control ports, and they all seem to work fine. But 
> i do need a control port output at the plugin, so that a response can be 
> sent to the plugin gui (which is also started fine by qtractor). So i 
> created a control port as output of the plugin. Now, when i change the 
> data of this port from within the plugin, the GUI and qtractor do not 
> recognize that the value has changed. Do you know if there's such a 
> mechanism?
> 

hmmm... now that you speak, there may be an issue regarding dssi output
ports--unlike the newer lv2--dssi output control ports are not being
marshalled to the gui. in fact, they are being just ignored. i guess, no
one (ie. me:) has ever found the need to date, so i never implemented it :o)

> 
> If my questions are to annoying for you, please do just forget them. But 
> maybe you got the hint for me, that i am missing all the time ...
> 

not at all. keep them coming.

cheers
-- 
rncbc aka Rui Nuno Capela
rn...@rn...