Just one line does it. In your case of uncompressed .avi: AVISource("J:\G.51.40.avi") or DirectShowSource("J:\G.28.50b.avi") (DirectShowSource is said to be not frame-exact and may even for uncompressed. avi discard frame 0 on Win7 Systems, at least it does here.) This single line typed into Notepad and saved with file extension .avs can be fed as input into HC. Why the .avs frontend ? Back when I came from ready-cooked apps I wondered too. But I learnt why: It is actually an advantage. (And i learnt a lot about Avisynth, BTW.) Developers do not want to reinvent the wheel, for a good cause: The wheel is already there, and maintained by wheelmakers. A multitude of Decoders are there, constantly developed and improved. So it may well be more elegant to call available and up-to-date decoders for Decoding and for the Encoder concentrate on implementing the main task: Encoding.