Scaler

Back in the original days of DOS, games ran on specific resolutions on CRT monitors (and occasionally televisions). Limited hardware required these games to run on what is today considered extremely low resolutions. A Scaler is like a filter, that reprocesses the emulated screen before it is drawn on the physical monitor, and enables old games to take on a slightly updated look (or stylized look).

COULD SOMEONE EXPLAIN HOW TO ACTIVATE THE FILTERS, PLEASE?

Examples

These screen shots (of Doom) represent a small section of the full game screen, and have been blowup 200% to better show how the image is being altered. Some effects are more subtle or visible depending on the range of colors displayed on the screen at individual moments.

Scaler	Example
normal2x normal3x
advmame2x advmame3x
hq2x hq3x
2xsai
super2xsai
advinterp2x advinterp3x
tv2x tv3x
rgb2x rgb3x
scan2x scan3x