How to record a screen video

Question

When I want to analyze a piece of music or watch a video lesson — I need to be online.
What alternatives do I have out there?

In corona-times it might be a quite useful and frequent problem:
How to copy a video (of a teacher), or How to recorded and saved a video on your device.

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Edit:
As this question is asked to be representative for anybody — answers for any system are welcome.

Answer 1

There isn't much detail here about your operating system, your browser, what service the video is hosted on, etc.

For starters, try seeing if you can download the video. If it's an educational website/service, there's a good chance you'll find success just locating a download/save button.

As @user66401 suggested in a comment, you can use YoutubeDL to download from youtube and a few other services; if it's on youtube, I would also recommend taking a look at YtMP3 which is a lot easier if you don't have experience operating from the command line (which is where YoutubeDL runs).

You could also try using built-in screen recorders; on Windows 10 at least, you can use Win+Alt+R to start screen recording and just play the video, and when you're done press the same combination or click the stop button on the control bar. If that gives you an error, try opening the Game Bar with Win+G and manually starting a capture. It's designed for games but it's just a simple screen recorder so there's no reason you can't use it for anything.

Answer 2

You don't say what operating system you're running. If you have a modern one, you may have the software you need already installed. Have a look at How to Record the Screen on Your Windows PC or Mac