BatchGuy is a free app created to extract streams from multiple ripped Blu-ray discs, create batch AviSynth scripts, apply global x264 encode settings for each video extracted, and easily mux items into a .mkv file.

BatchGuy is not an AviSynth editor. It has minimal AviSynth syntax capabilities. It allows you to copy/paste AviSynth syntax into it, and it will create a (.avs) file for each video you extracted from your Blu-ray discs.

BatchGuy is not an x264 encoder. BatchGuy will create a (.bat) file that you can use to run the x264.exe encoder. BatchGuy will not extract streams from Blu-ray discs for you. BatchGuy will allow you to pick which streams you would like to extract and create a (.bat) file that will use eac3to.exe to extract the streams.

Because this was a niche developed app for Blu-ray geeks, you may need a few things depending on your requirements. These include:

AviSynth 2.5+ and all relevant plugins (required only for encoding)
Blu-ray discs
eac3to
Microsoft .Net Framework 4.5+
Windows 7, 8, 10
vfw4x264 (just needed for encoding)
x264 (just needed only for encoding)