240p video
In order to save costs and also to present a stable image on interlaced displays most games developed before the year 2000, and hence all the consoles and arcade games that played them, are rendered in a resolution around 320 pixels wide by 240 pixels high, commonly referred as 240p. This video mode is actually a hack on top of the NTSC standard, but it works on all SD displays without issues. The trick is to paint only even lines, and instead of painting the odd ones paint the even lines again. This is what causes our beloved scanlines on CRTs; they are actually part of the image.
Why does all this matter? Simple, this 240p video mode is not considered by displays, and they process it as if it were 480i video, generating even more problems and delay in the process.
