Timed headings a creator adds in the description. They become the jump marks under the player.
Also called: video chapters, description timestamps
Chapters are not a separate YouTube file. They are lines in the description that start with a timestamp, such as 0:00 and 2:14, followed by a title. YouTube turns those lines into the chapter bar under the video.
The first line must start at 0:00. If that rule is broken, the whole list is ignored. A chapters extractor reads the description and returns only those lines.
Extracted chapters are the creator's own marks. Generated chapters are a second pass over a transcript, written because the video never had marks. Those are different tools. One reads. The other drafts.
If you are studying a lecture, extracted chapters tell you how the speaker cut the hour. Generated chapters tell you how a model would cut it. Keep the source clear when you publish either list.
Timed headings a creator adds in the description. They become the jump marks under the player.
Chapters are not a separate YouTube file. They are lines in the description that start with a timestamp, such as 0:00 and 2:14, followed by a title. YouTube turns those lines into the chapter bar under the video.
Start with chapters-extractor, chapter-generator.