[Youtube] --live-from-start support for sequence / range download

Checklist

• I’m reporting a feature request
• I’ve looked through the README
• I’ve verified that I’m running yt-dlp version 2022.04.08 (update instructions) or later (specify commit)
• I’ve searched the bugtracker for similar issues including closed ones. DO NOT post duplicates
• I’ve read the guidelines for opening an issue

Description

Hi, I try to implement capability of youtube livestream download (–live-from-start), that we can determine from which sequence it starts downloads until live/current live, or range from sequence A to sequence B by changing some parts on extractor/youtube In my case this is working well as expected, and super useful, and I want to know what you guys think. Maybe if this is good enough I hope I can be push it upstream, or let this be just a feature request 😃

commit: https://github.com/mxvin/yt-dlp/commit/ecf8b603c2f6e1356ab13c8912c9d29111ecc0dd

my misplace comment on this feature (maybe related to that actual issue, maybe not): https://github.com/yt-dlp/yt-dlp/issues/2412#issuecomment-1100650248

Verbose log

No response

[pukkandan]

For this to be actually useful, the option needs to be time-based, not fragment based

[ohhai]

Any method of range selection would be useful, I think. Currently it’s almost impossible to download default length of long live streams (120 hours) to cut a small portion of it.