Re: (was Re: Adding a description text property for a track) non-free javascript and ytdl

[Yuchen Pei]

On Sat 2022-03-26 10:29:03 +1100, Yuchen Pei wrote:

> On Thu 2022-03-17 11:17:13 -0400, Yoni Rabkin wrote:
>
>> I realized that I don't know a lot about ytdl/youtube-dl and went to
>> have a look. As a result, I came across a potential show-stopper for
>> inclusion in Emms in any form.
>>
>> I was concerned when I saw that ytdl/youtube-dl has a javascript
>> interpreter built-in.
>
> If there were no mpv binding for emms, a proposal to add it would be
> rejected based on the same ground, because mpv by default supports
> playing all the urls supported by ytdl, through ytdl.
>
> So when emms plays a youtube video through mpv, it calls mpv, which
> calls youtube-dl / yt-dlp, which may execute js when streaming the
> video, free or nonfree.
>
> By contrast, I highly doubt the emms-info-ytdl would actually indirectly
> execute any js.  It calls youtube-dl -j (getting the json, as opposed to
> streaming), which probably only retrieve the metadata using a json
> parser and stops there without executing any js code, something like the
> command in [1], which youtube-dl youtube extrator runs some equivalent
> python code to get video formats, among other things.

Actually I'm not sure if that is correct, because -j returns the url of
various formats of the video / audio, which sometimes need decryption.
I just did youtube-dl -j on a video which I could not get a plain url by
wget, and it returned urls that were not included in the result from
wget.  So the emms-info-ytdl could be indirectly running nonfree js
through youtube-dl as well.

Best,
Yuchen

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