SofdecVideoTools
https://github.com/Firebow59/SofdecVideoTools
I'm posting this a set of tools I found that is a lot better than the Sega Dreamcast Movie Creator in the Resource Database.
These tools can be used to create Sofdec videos, which XML1, XML2, and MUA1 use.
They can also be used to scale videos to fit so that they don't need to be cropped or squished.
They can also extract and convert existing Sofdec format videos.
There are 4 programs the creator made and included. This is how the creator describes them:
"SFDCreator - Automatically converts and muxes input audio/video into a brand new Sofdec file.
SFDExtractor - Extracts the contents of SFD files, and converts them to modern formats by default.
SFDPlayer - Plays SFD files (via re-encoding audio, since FFplay has issues with SFD audio playback).
SFDVersionDetector - Detects the version/muxer used for SFD file(s)."