Y/C Delay Controls are required to minimize or correct artifacts that occur when the luminance (black & white) channel and/or one or more color channels in a video signal are not properly synchronized.
display or video source suffers from Y/C delay error, there will be a
mismatch in the timing among the luminance and/or color channels, with
resulting visible misalignment in how colors appear in onscreen images.
A display exhibiting Y/C delay may look similar to a CRT projector with
convergence errors; and if the delay is severe, it may seem that the
picture is not well-focused.
Y/C delay error can occur in the display, in a video source (DVD
player, cable or satellite set-top box, game console, etc), or at
multiple points in the video signal chain. Regardless of where the
error occurs, the display should provide controls that allow the delay
to be minimized or eliminated. To be most effective, Y/C delay controls
should work independently for each physical input coming into the
In many cases where a Y/C Delay control is available, it will only
adjust the luminance channel timing in relation to the color channels
collectively. However, there are cases where delay errors may occur in
multiple channels -- for example, luminance may be arriving before
blue, and red may be arriving after blue; in this situation,
synchronization of each channel is required to address the errors.
Some external video processors/scalers provide per-input Y/C delay
adjustment, while others may provide more elaborate controls that allow
adjustment of multiple channels.