For this tutorial we'll be looking to replicate more functionality commonly found in professional hardware video mixers commonly used by VJs such as the old school WJ-MX30 including making use of a Downstream Key for masking the final mix and a variety of preset transitions and standard effects that can be easily accessed via a main control panel.
One the advantages of a simplified frontend setup like this is that it is much easier to see at a glance all of the "useful" controls needed during performance while continuing to have a more powerful rendering configuration behind the scenes.
Unlike a dedicated hardware mixer, this setup can be modified in any number of ways, such as the addition of a Syphon Output to another application or receiving DMX to change clips and other settings.
1. Mix and Transition Modes
In the 'Workspace Inspector' create A and B layers and group them into a Mix.
Use the 'Layer Composition Section Presets' for the A and B bus to store mix and wipes, then set each to trigger from a button in a Control Surface plugin.
2. Effects A and Effects B
For each bus create a Control Surface plugin and for each noteworthy stylize effect parameter add the appropriate slider or button.
For utility effects such as Color Correction, it can be useful to set up a separate dedicated Control Surface with parameters for both A and B.
3. Downstream Key (DSK)
The Downstream Key module applies a finally masking stage to the Mix group. The DSK can switch between using either the A or B bus, an external camera, or the matte generator as its source, as well as an additional "feedback" option which routes the mix output back into the DSK for unusual results.
Add a background layer behind the Mix group to display the Matte generator or a solid color.
4. AV Sync Modes
Add an Audio Analysis plugin and per-bus LFO plugins to automate control of parameters. Use AV Sync buttons in Control Surface plugins to change sliders, buttons and other parameters between manual control and the automated data-sources.