Mostly a recap of what I've posted previoously because AWZ Screen Recorder Pro is today's GOTD...
There are 4 ways to record or save video from or with a PC/laptop: maybe the most obvious is to use a camera to record the screen, which is actually done sometimes; you can download and save the stream, e.g., YouTube, which is usually the best quality, but subject to DRM; you can record the stream that's displayed, e.g., over an HDMI cable, which is also subject to DRM; and you can save/record the actual display, which is what AWZ Screen Recorder Pro does. Recording the screen is Not subject to DRM, offers the most flexibility, and doesn't require special hardware. That said, there are challenges... you need to be able to write the steam of video to disk in real time, so a fast SSD with sufficient disk space helps. It also helps to have the fewest possible processes running. To make the audio/video stream small enough that it can be written to disk in real time you must compress it, which happens when you encode the audio & video, and that takes CPU, & sometimes GPU processing -- how much *horsepower* is needed varies with the video frame size & codec [COmpressor / DECompressor] used. Quality and frame rate can be quite good with screen recording, but unlike recording the actual video stream, quality can depend on the display hardware used -- if the picture on your screen doesn't show accurate colors or shadow/highlight detail, that's the picture you'll record.
Windows has some builtin tools that may work as well as many 3rd party apps for you, because the Microsoft encoder isn't too bad, while many of those 3rd party tools use ffmpeg, which while not a bad set of code libraries by any means, was Not designed for capture. I like Ashampoo Snap because it lets you choose the video codec - I've had luck with the x264VFW codec. Most people really into this sort of thing probably use OBS.
zdnet[.]com/article/how-to-screen-record-in-windows-10-or-windows-11/#:~:text=First,%20press%20Windows%20key+Alt,window%20for%20you%20to%20play.
videohelp[.]com/software/Open-Broadcaster-Software
videohelp[.]com/software/x264-VFW
videohelp[.]com/software/x265vfw
That said, playing video or a game requires some of the same hardware resources as recording your screen. If you want to be able to use 100% of those resources for the video or game you need to use screen capture hardware. You can buy both external boxes and internal cards, but some do support DRM, meaning you may not be able to record streaming video as is. Google and you'll find some currently working workarounds, e.g., possibly some HDMI splitters.
Note that over the years display-related tech has improved tremendously. Most players and displays are very good at scaling video on the fly [while it's playing], graphics drivers are getting better scaling-related features, and AI scaling is on the near horizen. The pipes that video's squeezed through however, haven't really kept pace. That means that video using smaller frame sizes and/or lower frame rates requires less video compression to make it through that pipeline, compared to video using larger frame sizes and higher fps. You may find that recording video at smaller frame sizes &/or lower fps actually looks better when played back because it doesn't suffer from as much compression. One way to take advantage of that is using anamorphic video frame sizes. It became widespread with DVDs, and though it still exists, it isn't as common since HD, and you'll find fewer software tools, including players available. The way it works is anamorphic video uses smaller frame sizes -- often full height but reduced width -- but with directions for or to the player to display it full size. The idea is that the reduced detail, with the player interpolating the values for missing pixels, is less noticable than the artifacts from the higher video compression that would be needed to make FHD video the same file size. Google for more info.
Do feel free to experiment [usually using smaller, shorter clips]... I don't believe anyone has a complete lock on this stuff, and through experimenting people are finding new tweaks daily. As an example, one of the things I found many years ago, and that still holds true today, is that noise can sometimes force a video codec to include more detail, thus reducing artifacts at higher levels of video compression.
From the download page comments...
"Screen recorder can never match the quality of direct play/record and the files created are huge, not appropriate for small HD on laptops."
The quality of the recording depends on the quality of the picture that's displayed and both the amount of video compression and the type of compression used. Those last two, combined with the length of the video, its frame size, and the number of frames per second [fps] determine the size of the video file that's recorded. When you record video from the screen the file size has to be small so it can be written to disk in real time. Since the software drivers for the graphics card or GPU may include features to improve the video &/or game display, the version recorded from the screen can sometimes be better than the original. The form factor of the deice you're using is irrelevant... both displays and video frame sizes are measured in pixels -- one pixel is basically the smallest dot that can be displayed, and can be any physical size -- and that's what matters when you're screen capturing video. Granted, today you're not yet going to see 4k cell phone displays, but there are plenty of 4k capable monitors & laptops, while FHD [Full HD or 10080p] is common. "small HD" doesn't really mean anything.
"For what reason would you record something from the screen.
Is sound also included? If I want to record something it just comes from the internet, the weirdest films can also be found there."
You can record online video streams that cannot be saved to a local copy because of DRM. You can also record game play to share, as well as demonstrations and/or tutorials. Sound [audio] generally can be included, though it may be purposely left out, or added afterwards, e.g., with tutorials.
"please be mindful of copyright and intellectual property rights when recording and sharing content from the internet."
(C) law is a minefield, especially nowadays with lawyers anxious to set precedents because AI. While very many seem to get away with putting (C) video online [X, TikTok etc.], many are getting sued &/or prosecuted, so please do be careful.