What are the main differences between DX, VST and Audio Units?
VST is a protocol that works on several platforms (Mainly Windows, MacOS, BeOS, and some Linux platforms use it as well) whereas DirectX is Microsoft Windows Only, and Audio Units are available only on the Mac. VST and Audio Units are dedicated to Audio processing whereas DirectX (DirectShow) enables you to manage any kind of streamed media (audio video, compressed data…).