Live Stream transcripts

Hello. This is a feature request vs bug, methinks.

Have you looked at extracting captions from a live stream. If you look at any example (https://www.youtube.com/whitehouse) of a live stream, while the stream is live (key), there are auto-generated subtitles delivered in the videoplayback file that streams in, embedded e.g.

https://r6---sn-8xgp1vo-p5qy.googlevideo.com/videoplayback?expire=1614211486&ei=PpU2YM-ULYm98wTm0L_gDA&ip=71.246.232.10&id=yhxmnlGtJ-g.1&itag=386&source=yt_live_broadcast&requiressl=yes&mh=zc&mm=44,29&mn=sn-8xgp1vo-p5qy,sn-p5qs7nel&ms=lva,rdu&mv=m&mvi=6&pl=18&initcwndbps=1717500&vprv=1&live=1&hang=1&noclen=1&xtags=lang=en:ttkind=asr&mime=text/mp4&ns=aD6U7aY6idhNPyXEqiXu6K0F&gir=yes&mt=1614189620&fvip=6&keepalive=yes&fexp=23983797&beids=9466586&c=WEB&n=lmOMV3MuzrpzRQ&sparams=expire,ei,ip,id,itag,source,requiressl,vprv,live,hang,noclen,xtags,mime,ns,gir&sig=AOq0QJ8wRAIgd0qHHqBF3aRir-pw93UKhFNuFxrlpe6OqyMerxsZ4JsCIHZK74UbKX7ig08-egt6vMDzP6g_7EhOyuOOoUXAkSVW&lsparams=mh,mm,mn,ms,mv,mvi,pl,initcwndbps&lsig=AG3C_xAwRAIgHa9tABbFKMiVQSnLLWa7iO_iu7pcVtrea43G-zdfGBUCIGbqOL15uN0-32Yki8s5vwXD2XDkvCBUgntS54w9xvjc&alr=yes&cpn=LW2TAYe5jfbjzMjx&cver=2.20210223.09.00&sq=664

Expired, of course, but an example, the payload here is:

ftypmoovlmvhd_@(mvex trex}trak\tkhd@mdia mdhd_UÄ!hdlrtextÐminf$dinfdrefurl ˜stblHstsd8tx3g
ftabsttsstscstcostszVnmhdemsghttp://youtube.com/streaming/metadata/segment/102015ˆ°D«Sequence-Number: 664
Stream-Finished: F
Ingestion-Walltime-Us: 1614189870022158
Stream-Duration-Us: 3320017000
Max-Dvr-Duration-Us: 14400000000
Target-Duration-Us: 5000000
Encoding-Alias: L1_Ag

Xmoofmfhd@traftfhdß’tfdtÏYztrun`^mdat<?xml version="1.0" encoding="utf-8" ?><timedtext format="3">
<body>
<p t="0" d="345">what&#39;s in the Declassified
report or when it comes out</p>
<p t="345" d="3750">because many elements of Italy
two years ago when when it was</p>
<p t="4095" d="910">first first came out if you come
to the conclusion that there</p>
</body>
</timedtext>

The timedtext is embedded in the file:

<?xml version="1.0" encoding="utf-8" ?><timedtext format="3">
<body>
<p t="0" d="345">what&#39;s in the Declassified
report or when it comes out</p>
<p t="345" d="3750">because many elements of Italy
two years ago when when it was</p>
<p t="4095" d="910">first first came out if you come
to the conclusion that there</p>
</body>
</timedtext>

It's not TTMLv3 but we get this text is associated with sequence #664 from the URL. The t= appears to be millisecond designation relative to the sequence chunk, and "d" appears to be the duration. But even absent that, the stream of text is there. Note it doesn't appear by default. It appears you need to insert into the "sparams" in the URL "xtags" to get the live captioning, but it appears if you try to insert it, it messes up the hash/key associated with it so it needs to be triggered on (cc_load_policy=1 in URL does NOT seem to work)

youtube-dl et al don't recognize this since it's not being delivered as a standalone subtitle file. Acts like there's no subtitles on the live stream since it doesn't identify as a subtitles file.

Thoughts?

jdepoix / youtube-transcript-api

Live Stream transcripts #98