I follow an incredibly talented musician Twitch streamer who creates covers of songs during his streams. He uploads vods of his streams to Youtube and these can be anywhere from 3 - 5 hours. I used yt-dlp and ffmpeg to process his videos so I could create a table of contents that contained a list of timestamps of when he starts playing each song. The 2nd step (which I haven't done yet) is to create a small site that lets me search for different song covers and create playlists out of them.

One of the reasons I enjoyed building this was because it was just for me. There was no pressure for it to be production-ready or to make a profit.