For your information this is commercial plugins that require you to register them to use them fully.
"AVISourceEx" - AviSynth has been able to read compressed audio and set custom pixel type for very long now.
"ConvertToRGB32Ex" / "ConvertToRGB24Ex" - might be faster - no YV12 conversion though.
"IPCSource" - if you need it. There are other frameservers from Premiere, Vegas and ULead Mediastudio. See
http://www.debugmode.com/. Guess that mostly leaves "Flask"/XMPEG as the only app, as far as I can see.
Link2 functionality is now supplied in ffvfw, to allow fake AVI's to be created containing AviSynth material.