Once you have your MP4 file(s), you can use these tools to create a feature-length video:

For rapid merging of many files without re-encoding, you can use the command line with ffmpeg: ffmpeg -f concat -safe 0 -i filelist.txt -c copy merged.mp4 . To help you further, could you tell me:

Offers free online tools to merge multiple MP4 files, trim, crop, and edit, with support for videos up to 1 hour.

In your browser (Chrome, Edge), press F12 or right-click anywhere and select Inspect to open the developer tools.

A free desktop application for converting and editing video files into MP4 format.

Free, open-source software for Windows, Mac, or Linux to compress or convert videos into high-quality MP4 files.