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NTSC filters replicate the analog signals that the consoles output to the TV. They vary in quality, with the lowest quality being RF, then composite, then s-video and RGB (SCART)/YPbPr (Component) being the highest quality. Many emulators have NTSC filters built into them. They can also be separately downloaded as filter plugins. These filters were developed by [http://slack.net/~ant/libs/ntsc.html blargg] for specific consoles. Other NTSC shaders have been created which are different from Blargg's implementation.
The level of blur in RF and composite signals are needed for [[dithering]] to blend on Genesis/Mega Drive. S-video, and RGB are too clean to blend dithering. However, [https://github.com/libretro/common-Other shaders/blob/master/crt/shaders/snes-hires-blend.cg snes-hires-blend.cg], [https://github.com/libretro/common-shaders/tree/master/dithering dithering shaders], or [https://github.com/libretro/common-shaders/blob/master/crt/shaders/tvout-tweaks.cg tvout-tweaks.cg] may work fine for can be used to achieve the purposesame level of blur.
Many SNES games were developed with the color distortion from these signals in mind, such as Chrono Trigger, with shifted values that make blacks look brown and borders look purple (this is due to TV color range being 16-235, as opposed to standard PC color range of 0-255), which would be output properly with NTSC colors, and Kirby's Dream Land 3, with vertical line patterns combined with high horizontal resolutions producing translucency effects when blended by the analog signal.
==Description==
[[File:NTSC settings.png|thumb|350px|Chart showing the relative difference values between Composite, S-video and RGB]]
===RF===
A shader made by Aliaspider intended for processing emulator images for output to a CRT TV connected to PC via VGA-to-RGB adapter. This shader uses code from the GTU CRT shader to provide emulated signal bandwidth blur, as well as TV color level conversion. This shader is equivalent to the Blargg's NTSC filter RGB preset when the signal resolution is set to a high level and TV color levels are enabled. Works with any resolution without issues, lower signal resolutions result in blur that blends higher input resolutions, allowing dithering to be blended and SNES hi res translucency to work.
===Other===
* [https://github.com/libretro/common-shaders/blob/master/crt/shaders/snes-hires-blend.cg snes-hires-blend.cg]
* [https://github.com/libretro/common-shaders/tree/master/dithering dithering shaders]
==Gallery==
