fix plugin analysis for variable i/o plugins

diff --git a/libs/ardour/plugin_insert.cc b/libs/ardour/plugin_insert.cc
index 6720b41f9321105ad189e730522cad5c64286461..11117e720c445588940df9f39059d51c86fca3c6 100644 (file)
--- a/libs/ardour/plugin_insert.cc
+++ b/libs/ardour/plugin_insert.cc
@@ -2862,7 +2862,14 @@ PluginInsert::get_impulse_analysis_plugin()
                // during init() -- most notably block_size..
                // not great.
                ret = plugin_factory(_plugins[0]);
-               ret->configure_io (internal_input_streams (), internal_output_streams ());
+               ChanCount out (internal_output_streams ());
+               if (ret->get_info ()->reconfigurable_io ()) {
+                       // populate get_info ()->n_inputs and ->n_outputs
+                       ChanCount useins;
+                       ret->can_support_io_configuration (internal_input_streams (), out, &useins);
+                       assert (out == internal_output_streams ());
+               }
+               ret->configure_io (internal_input_streams (), out);
                _impulseAnalysisPlugin = ret;
        } else {
                ret = _impulseAnalysisPlugin.lock();