If a video is streaming on a computer but not seen is it really playing?

My laptop maybe having an inevitable system killing/death knell possibly involving the graphic cards. Recently, I get a very vague blue screen of death and my computer reboots itself. Prior to the crash, the video gets distorted and overly pixelated and jumpy while the sound remains perfectly fine.

Always (so far) after it reboots, the system is fine. It only happens when I'm watching a video and usually when I have my computer on for a while and my computer seems to be overheating.

But out of curiosity, if one has an online video is playing on one browser tab but it's playing in the background while another browser tab is displayed on the screen, is the video card still being used for the streaming video and is the video technically being played visually in the computer system despite not being shown in that time frame to the computer's user or is it just technically playing the accompanying audio until the video is brought forth into the foreground then the video card is once again activated to do its thing and graphically depict the video?