Many streaming websites, such as Netflix and Disney+, use DRM to protect their video. When the user wants to do screenshot, video recording, or share screen via video conference, the video content becomes black. My research only leads me to those DRM solutions such as Google Widevine and Apple FairPlay, which explains how are keys managed such that only authorized user can decrypt video and play. But I am more curious on what technology is used to blackout the video when doing screenshot.
I found that this has something to do with enabling/disabling hardware acceleration, such as this one Why does disabling hardware acceleration in Google Chrome allow Discord users to stream sites like Netflix, TV streams, etc?, but I was unable to find any concrete technological explanation about it.
Say that I placed a video clip on my own website, I want everyone to view it while I want to prevent it from being screenshot/recorded, can I use this technology to achieve this objective?
My research only leads me to those DRM solutions
That is what is used.
The video is blacked out because it (in theory, ideally) remains encrypted all the way to the display device. HDCP is used between the graphics card and the display device.
I found that this has something to do with enabling/disabling hardware acceleration
Yeah, if the hardware isn't handling the encrypted video, then the video must be encoded at the software end and then it's basically free game for everything to copy. What you've found is an incompatibility. Note that when you disable the hardware codecs or otherwise break DRM, providers such as Netflix will give you low quality 720p video.
Say that I placed a video clip on my own website, I want everyone to view it while I want to prevent it from being screenshot/recorded, can I use this technology to achieve this objective?
Yep, use one of the DRM providers.
Just keep in mind that while compatibility is good, it isn't perfect. Also, if someone really wants your content you can't stop them from getting it. HDCP isn't perfect... there's little stopping someone from plugging in a buggy HDMI splitter and getting video in the clear.