ReelSteady-Joiner VS editly

If you have the max check this out- https://github.com/rubegartor/ReelSteady-Joiner

What's the best way to combine these files to a complete MP4 while keeping all the metadata intact? I did a bunch of google searches, but all the methods I found completely screw all the metadata / additional data streams in the file. I've tested "ReelSteady Joiner" (which just runs ffmpeg in the background), I've tested ffmpeg and udtacopy as suggested on the GoPro Labs page, I've tested various different ffmpeg versions and commands I found through Google.

The easiest fix is to get this program: https://github.com/rubegartor/ReelSteady-Joiner

If you want to stitch these files together and retain gyro data for stabilization, download and use this tool. It will do all the work for you and output a single, big file.

Sounds like you already have a process for most of this, but I found https://github.com/mifi/editly to be incredibly helpful to run ffmpeg and make my little time lapse video. Could be useful for others

For example, this declarative video editor lib has JSON configurations for defining an output video:

Maybe this tool helps: https://github.com/mifi/editly

You seem to misunderstand what ffmpeg is for - namely the stream conversion of media. Only limited filters are available. You can write your own shaders and use cli tools like https://github.com/mifi/editly for automation surely

I used Editly to make a clip of several videos with transitions and screenshots. It worked out great with me just editing the json5 file to tweak things

https://github.com/mifi/editly (Node JS)

It's intended to work nicely with Editly, a CLI-based https://github.com/mifi/editly

The way I would do it would be using MoviePy (for Python). You may also have luck with editly (JavaScript). MoviePy has functions to create a TextClip, Images and overlays. It sure is possibly with ffmpeg filters - transparency mixing filters etc. yet you'd get faster results with modules like MoviePy / editly.