Originally posted by: Moth3r
Apparently mplex comes from the MJPEG tools project, however I can't find much guidance on how to actually use it and what command line switches it takes.

I'd think "mplex -?" or "mplex --help" should display usage info.
The most basic form is "mplex -o output_file input_file1 input_file2 [input_file3 ...]"

I used the Linux version of mplex to mux Moth3r's mono_ntsc.ac3 with video ripped from Doctor M's RTW.
That was DVD-compliant, of course, but [my version of] mplex has a command-line switch "-f" to specify output formats, including generic MPEG1 and generic MPEG2 among others.