Editing SCART (section)

=== RGB overlays ===

SCART enables a device to command the TV to very quickly switch between signals, in order to create overlays in the image. In order to implement [[captioning]] or [[subtitles]], a SCART set-top box does not have to process and send back a complete new video signal, which would require full decoding and re-encoding of the color information, a signal-degrading and costly process, especially given the presence of different standards in Europe. The box can instead ask the TV to stop displaying the normal signal and display a signal it generates internally for selected image areas, with [[pixel]]-level granularity. This can also be driven by the use of a "transparent" color in a teletext page.