[Qtractor-devel] Can't get more than 1 LinuxSampler track to work in Qtractor

[Frank N. <bea...@we...>]

Hi Rui&all,

not sure who is at fault here (likely me :-), but maybe some from the Qtractor
community can help..I am trying to set up a simple session with Qtractor and
LinuxSampler: 2 MIDI tracks, each holding an instance of LinuxSampler (LV2) as a
plugin. When I attempt to load an .sfz file into the 2nd instance, I get an error message:

The audio output device 'Plugin' cannot be dropped from this sampler channel!
The MIDI input port 'Plugin' cannot be altered on this sampler channel!

Let me describe what I am doing, step by step:

- Start QJackctl, start JACK, start Qtractor
- Qtractor: Create new track, type MIDI, add plugin -> LV2 -> LinuxSampler, confirm with ok
- Start QSampler, click on that track, "Setup channel", select SFZ engine and some .sfz file, confirm with ok
  MIDI Input Type is "Plugin", Device: MIDI Plugin Device 0
  Audio Output Type is "Plugin", Device: Audio Plugin Device 0
- Qtractor: Connect MIDI keyboard to Qtractor, play into that track 

= all fine so far =

- Qtractor: Create another track, again type MIDI, add plugin -> LV2 -> LinuxSampler, confirm with ok
- In QSampler, click on that track, "Setup channel", select SFZ engine and some other .sfz file, confirm with ok
  -> at this point QSampler says "Channel 1  Some channel settings could not be set.  Sorry."
     and in Qtractor's console I see:
     Starting disk thread...OK
     EQ support: no
     Stopping disk thread...OK
     Starting disk thread...OK
     EQ support: no
     The audio output device 'Plugin' cannot be dropped from this sampler channel!
     The MIDI input port 'Plugin' cannot be altered on this sampler channel!

     though it then continues to say:
     ...
     Instantiating LADSPA effect 'triplePara'.
     LADSPA effect 'triplePara' activated.
     Scheduling '/tmp/x/wa_synth_drums/drum kits/sfz/z_all percussion dissonant hits.sfz' (Index=0) to be loaded in background (if not loaded yet).
     Loading sfz file '/tmp/x/wa_synth_drums/drum kits/sfz/z_all percussion dissonant hits.sfz'...OK
     Loading sfz instrument ('/tmp/x/wa_synth_drums/drum kits/sfz/z_all percussion dissonant hits.sfz',0)...OK
     Caching initial samples...OK

Net effect is still that on this new track no audio is being played out. The
first track continues to work fine.

Used versions:
- Qtractor 0.8.0 (built from Git on Dec 6th)
- libgig, liblscp, linuxsampler, qsampler built from today's svn state

Have I misunderstood something about how tracks and channels of Linuxsampler
are supposed to work from within Qtractor? Do I need to change something in
Qsampler before confirming the properties of a new channel?

Thanks,
Frank