I have found the Momento 5 Dashcam app - for both Mac or Windows - essentially useless for me... All I want is to pull some video clips and it takes an eternity to launch the app and find the file I want to export. Since I generally know about the time I want to extract, I wanted a simple command line tool to pull out the bits... This got me headed down the rabbit hole that is the AVI file format. So I figured I could build a tool to pull out the contents I want for a time range I want and pull the video bits together without launching any app - AVI is a standard format, right?
WORK IN PROGRESS
The parse_video.py tool parses out the AVI into the associated bits.
If you have ffmpeg installed and are using either Linux or Mac, you can use convert2mp4.sh to take a single file and export a video (with the picture-in-picture) for front and rear cameras. Depending if you record with the rear camera reversed or not, it may need a little tweaking. I found this much more efficient that trying to load the videos from the custom app that you can download.