Upmixes all 2 channel AC3 files in a folder. Creates 6 channel (5.1) files @ 448 bitrate. Audio can be increased (open AC3upmix.cmd in notepad to change volume).

Install avisynth v2.5.7

Unzip soxfilter.dll into the, usually, C:\Program Files\AviSynth 2.5\plugins folder.

Download and unzip AC3upmix.zip to a folder. Put the AC3 files in the same folder.

Double click on AC3upmix.cmd. Thats it!