Previous generation consoles upscaled standard definition games to HD either via software (bad upscaling) or hardware (good upscaling). Now Sony’s Shuhei Yoshida has confirmed (via Twitter) that the PlayStation 4 will feature hardware upscaling to HD.
This means, in addition to improved visual quality, that the GPU won’t have to do the extra lifting by upscaling the image to HD, or from 720p to 1080p.
For example, Call of Duty Ghosts will run at 720p natively on the PS4, but will be upscaled to 1080p. Battlefield 4 runs at 900p, but will be upscaled to 1080p as well.
Hardware-based upscaling means that there is a dedicated chip that’s optimized to deliver the best performance and visual quality. Upscaling is also used to show standard DVD videos in HD, as well as older games from previous generations, such as the PS2.
By comparison, the PS3 added scaling as a software update, while the PS4 will have a built-in hardware scaling chip from the get go.
UPDATE: As one commenter pointed out, Call of Duty Ghosts will run in 1080p natively on the PS4.