I

index palette

A DirectDrawPalette object whose entries are indices into another palette object.

IRE

IRE, an acronym for International Radio Engineers, is a scale of values ranging from 0 to 100 that defines the brightness level of a broadcast video signal. The spectrum of low-to-high IRE values describes increasing brightness levels in a video signal. At 7.5 IRE brightness units — the "black cut-off" threshold for an NTSC signal — the electron guns of an NTSC display device are cut-off and do not display images.