YouTube-dl has an interpreter for a subset of JavaScript in 870 lines of Python

I'd have to read up on the specifics as well, but I think basically Youtube uses a lot of obfuscated, rapidly and automatically changing Javascript code to fetch the video data. A project like youtube-dl has to run this code to be able to download videos, because that's what's happening in the browser as well.

Re: YouTube-dl has an interpreter for a subset of JavaScript in 870 lines of Python

#8

Post by hadrien01 » Sat, Sep 10, 2022, 6:37 PM UTC

anony23 wrote: post #2

What purpose does it serve?

It's used in the YouTube extractor: https://github.com/ytdl-org/youtube-dl/blob/d619dd712f63aab1...

I believe YouTube limits your bitrate if you don't pass a specific calculated value; it's possible youtube-dl has to parse and eval JS to get it.

Re: YouTube-dl has an interpreter for a subset of JavaScript in 870 lines of Python

#9

Post by RicoElectrico » Sat, Sep 10, 2022, 6:39 PM UTC

hadrien01 wrote: post #8

anony23 wrote: post #2

What purpose does it serve?

It's used in the YouTube extractor: https://github.com/ytdl-org/youtube-dl/blob/d619dd712f63aab1... I believe YouTube limits your bitrate if you don't pass a specific calculated value; it's possible youtube-dl has to parse and eval JS to get it.

> I believe YouTube limits your bitrate if you don't pass a specific calculated value

It's starting to become Widevine bullshit all over again.

Re: YouTube-dl has an interpreter for a subset of JavaScript in 870 lines of Python

#10

Post by homarp » Sat, Sep 10, 2022, 6:46 PM UTC

the tests for it: https://github.com/ytdl-org/youtube-dl/blob/master/test/test...