Metaplugin is a flexible piece of software that loads other VST/VST3 and AU plug-ins and lets you interconnect them arbitrarily. It is available in VST/VST3, AU and AAX format and can therefore also be used to bridge plugins in hosts that do not support either the VST, VST3 or the AU format. Plug-ins can be dragged onto the freely resizeable interface, connections are made by dragging cables between the in- and outputs of the loaded effects. Chains can be saved so that the user can build custom effects out of existing modules.
Metaplugin has its own internal bridge between 32 and 64-bit plugins, enabling the use of older 32-bit VST or AU plugins in 64-bit hosts. It also works the other way: want to keep using an older 32-bit DAW with new 64-bit plugins? With Metaplugin 3.4 this is now possible: load the 32-bit version of Metaplugin and start using 64-bit plugins in it.
As an extra, a flat-summing four band crossover filter and a mid-side matrix are included in the package. This way, multi-band and mid-side versions of existing plug-ins can be built instantly.
Metaplugin supports up to 8 in-out-channels. The user can load it, e.g., into a 7.1 channel of the host and chain plug-ins on all six channels (and across channels). Also, the dry/wet amount going through each of the loaded plug-ins can be adjusted (shift-clicking on the plug-in rectangles turns them into horizontal sliders).