I have a video file with AC3 (2 channel) audio, and the left and right channels are reversed. It's definitely the source, and not my config. I could play it back properly by changing my AC3filter ...

Yep - normalizing is what you're looking for. I always decode to .WAV, then run it through CoolEdit 2000 to clean up any noise and normalize the audio to 98%. I then save back to .WAV, and use ...

A compressed version of files, popularly known as zipped files are convenient but also prone to errors. So, when you attempt to open such files using freeware ...