Some that seems suitable for your use case is avidemux and vidcutter, you might want to check them up. Suggestions on a lightweight video cutter.This tutorial shares a tip on how to use Handbrake to convert MKV to MP4, AVI, MOV, WMV. There's even instructions for that specific task here. Many people faces error when converting MKV video with Handbrake. AviDemux is free, simple to use and I'm aware of people using it to stitch tens of thousands of images into video using it.

If I were you, I'd use AviDemux to combine the images into video then import that into Vegas. New user to video editing with Vegas pro 14 Something for cutting videos, free and simple, I'll go with avidemux. I am using AviDemux (official repo) but doing very simple tasks. Remember Windows Movie Maker back on windows XP? What's the equivalent on the Manjaro KDE repos? There's a potential that the Speed Editor would save me a lot of button presses on the keyboard, since I do all the editing on the keyboard in Avidemix. I just stumbled upon the Blackmagic Design DaVinci Resolve Speed Editor and was wondering if someone could tell me whether it would be compatible with Avidemux, which I'm currently using to quickly edit some VHS rips. DaVinci Resolve Speed Editor for Avidemux?

Xmedia recode tutorial mkv to mp4