A german court ruled youtube's obfuscation of video request signatures is an effective technological protection measure. YoutubeIE._decrypt_signature in youtube_dl/extractor/youtube.py bypasses this.

As a philosophical issue, since the youtube-dl code is running the cipher off of the code provided by youtube, just as my browser is, why is my browser not similarly circumventing this protection?

At least with CSS a key needed to be found by means separate from actually watching the DVD and wasn't shipped with the user in the same package as the video itself.

> why is my browser not similarly circumventing this protection?

Because your browser also runs the javascript that displays the ads (unless you've also blocked them, which I think could also be considered a "circumvention measure", IANAL).

If ads we're required, they could certainly not stream a video until the ads have been watched (or at least downloaded and the correct amount of time has passed), they could also insert ads as segments of video without having to transcode all videos for every user, but they don't.

> they could also insert ads as segments of video without having to transcode all videos for every user

That would work in a livestream very well, but not in a video. Imagine everyone getting adverts in the voice of live streamer in the different times of the livestream, and live chat getting time-dilated to compensate, without the streamer itself noticing.

Sorry this isn't really an argument. How can someone not make the argument regarding the browser in court and not have it align with the German court's prior finding?

Saving videos

Youtube-dl doesn't do anything your browser doesn't do already do when accessing said video.

Also, I asked what is being circumvented, not what the tool does.

It boils down to the intention. The intention is to download videos to your computer (as viewable mp4 files for end users) which isn't legal, as they are intended to be streamed (or possibly removed in the future) with ads, stats, analytics, recommended etc.

I definitely don't defend this and I know that this whole copyright and DRM thing is fundamentally flawed by design, but it unfortunately works this way legally.

If it boils down to user intention then you can't also argue the tool is circumventing anything. Either mimicking a browser and working the way google expects any client not written or authorized by them, such as a web browser, to is ok or it's not.

I don't think saving things is in general a copyright violation?

Knowingly and intentionally obtaining unlicensed content is a violation. Unauthorized redistribution is a violation. Saving and copying things isn't (AFAIK) a violation.

Saving things is creating an unauthorized copy, which is fundamentally the basis of copyright. Some territories have explicit allowances for personal copies but many don't.

There are a variety of reasons that you can have a copy of a copyrighted work it a way the copyright holder didn't intend, such as time shifting or media shifting.

And in many juristictions they are explicitly defined, and don't apply to copyrighted work generally, only when acquired under specific circumstances.

Format shifting is explicitly illegal in the UK for example, and timeshifting is restricted to works obtained from a broadcast source by the person performing the copy, and not to an on-demand one, in many territories.

Although the OS might do that as well when you watch a video and put the computer into hibernation mode.