[Ardour-Dev] Ardour VST freeze

Martin Profittlich martin at profittlich.com
Sun Mar 1 11:07:46 PST 2009


The current SVN version of ardourvst (2.0-ongoing, rev. 4709) crashes
when I try to freeze a track with a VST plugin (Guitar Rig in my case).
This happens because during freeze two threads are accessing the plugin
at the same time. If I put a mutex around processReplacing() in
vst_plugin.cc, the freeze completes, but of course with a horrible
performance due to locking (xruns galore) and with audible artifacts,
because time-based effects get confused by the merged stream.

I guess the two threads are the freeze thread and the regular JACK
thread. Is this correct?

I think the solution would be to prevent the JACK thread from accessing
the plugin during freeze altogether, but I'm not sure what the proper
way to do this is. Any suggestions?

Many thanks,

P.S. Is VST chunk load/save planned for the 2.8 release? I tried to hack
something together, but it doesn't work, yet.

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