WAVI AutoMUX lets you choose directories which contain WAV and AVI files- and it will mux each wav into an avi with matching name.

I coded this some days ago to deal with the tedious muxing of mute AVIs which are created by Resolves processing of DNG sequences, which were recorded with a separate WAV file, like in most DNG recording cameras like Blackmagic, Sony FS700 or Magic Lantern. (at the moment just WAV/AVI, other formats might be added by request)

you can get it at: http://www.fatpigtures.com/wavi-automux.html you will need ffmpeg in its directory.

Let me know what you think.