High definition (HD) generally refers to video with significantly more detail than standard definition (SD). SD vs. HD: What's the Difference? | BroadbandNow.com
The new open-source codec, AV1, allows for 4K streaming at the same file size as old 1080p files. Soon, "HD Area" will mean 8K AV1 files that look transparent to the human eye. hd area movies