This is the code that generated the font in my video "bad_apple.otf". The frames were extracted with FFmpeg, then vectorized with potrace. The actual font was created using a combination of opentype.js and fonttools (well, only the ttx command line tool) I didn't really make it user-friendly, but here's a description of how to use it anyway:

0. You'll need working installations of FFmpeg, potrace, Bun, opentype.js (NOT installed through npm, but in a folder called "opentype.js" because I hacked on it a bit in the process of making this. A vanilla install (latest NPM version, not master) should work) and fonttools. Make is also useful, but not required. Part of the pipeline uses svg-path-commander, but you can do bun i to install it.
1. Obtain a copy of the original video. I used a 1440x1080 one; the height is hardcoded in some places
2. Extract all the frames with FFmpeg (the "bad-apple-frames" folder is .gitignore'd for this purpose). Make sure to extract to BMP, since potrace doesn't support any compressed image formats (warning, this will take 30GB of disk space)
3. Run bun run trace-frames.ts to create "frames.json", a file with all of the frames vectorized in order (~120 MB; this will take a few minutes)
4. Run make to execute all of the other steps (if you don't have Make, you'll need to read and execute the Makefile manually)

The font generation pipeline generally looks like this:

frames.json --(make-base-font.ts)-> font.otf --(ttx)-> font.ttx --(make-ttx-template.ts)-> font.ttx.template --(inject-ligatures.ts)-> font-withliga.ttx --(ttx)-> font-withliga.otf (finished product)

Most OpenType implementations aren't made for 512-long ligatures^{[citation needed]}. I've tested quite a few in the process of making this, so here are their limits:

• Windows Notepad can display very long ligatures. However, if the font includes any with a length above 512, it starts to lag. Additionally, the text layout glitches out when rendering such a ligature.
• Word seems to have the same limits as Notepad, but it gets increasingly laggier with the length of the rendered ligature.
• Notepad++ (when using DirectWrite) can render up to 297 fine, but 298 is rendered as (ligature 99) + (ligature 99) + (ligature 99) + (single non-ligature character)
• Firefox (and therefore most apps on Linux I think) ignore any ligatures longer than 64.

TL;DR: I've only gotten the font to render fully on Windows, in Notepad. It may work on Macs. I don't know, I don't have one.