Alternative scanning methods

[Samhain]

So if I understand correctly, all current displays scan images from top to bottom. This is a relic left over from the old analog CRT days and was kept for backwards compatibility reasons.

Is it possible to scan the entire image/frame all at once?

Is anyone working on alternative scan methods?

Would someone like nVIDIA be able to upgrade the G-Sync firmware/driver to enable alternative scan methods?

What would the best alternative scan method be?

[Chief Blur Buster]

So if I understand correctly, all current displays scan images from top to bottom. This is a relic left over from the old analog CRT days and was kept for backwards compatibility reasons.

Is it possible to scan the entire image/frame all at once?

Is anyone working on alternative scan methods?

Would someone like nVIDIA be able to upgrade the G-Sync firmware/driver to enable alternative scan methods?

What would the best alternative scan method be?

Very excellent Blur Busters questions!

It is not just due to backward compatibility reasons, but also that it is efficient on a latency perspective. Graphics have traditionally been transmitted one pixel at a time over video cables, so raster scanning makes possible real time displaying "off the wire".

Plasma displays and some other displays already present the whole screen at once. However, that adds some potential input Lag, because you have to buffer the refresh coming on the wire, before presenting it all at once.

Since it is impossible to instantly transmit whole refresh from computer to monitor, we have to transmit the refresh sequentially. The simplest way is the status quo of the top-to-bottom scan. And that is the way we have been doing it for practically a century...!

G-SYNC is actually a first step in decoupling the transmission speed limits from the refresh rate, which means G-SYNC is already a small step toward instant full screen transmission and presentation Historically, 60hz was transmitted and scanned in 1/60second. G-SYNC mode changes that. Even at 60fps which now behaves as 60Hz, the transmission and scanout occurs more instantly (1 / 144sec). So even playing games capped at 60fps will still have less input lag, despite looking like a 60Hz LCD.

[Chief Blur Buster]

What would the best alternative scan method be?

It is still probably faster sequential scan, taken from a fast packet transmission cable (DisplayPort, which can theoretically transmit a 1080p 4:2:2 frame in only 2.3 milliseconds if using both channels) until we do random access refreshing or other exotic framerateless technology, or refreshing faster only where the eye is pointing at. This gets very exotic once we go away from sequential transmission and presentation, in a lower-lag way.