Video and Image Processing Suite User Guide

ID 683416
Date 2/12/2021
Public

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22.1.1. Color Bars

In this mode, the Test Pattern Generator II IP core produces a test pattern with 8 vertical bars, each covering approximately 1/8th of each output video line.

The sequence runs through the eight possible on or off combinations of the 3 color components of the RGB color space, starting with a 75% amplitude white.

  • Green: on for the first four bars and off for the last four bars
  • Red: cycles on and off every two bars
  • Blue: cycles on and off every bar
Figure 72. Color Bars Test Pattern with Border Enabled
Table 67.  Color Values for Each Color Bar Pattern in RGB and YCbCr Color SpacesThe table lists the values used for each color bar in both RGB and YCbCr color spaces for 8 bits per color sample. If the requested output is not in 8 bits per color sample, the IP core truncates or increases these values accordingly.
Color RGB YCbCr
White (180, 180, 180) (180, 128, 128)
Yellow (180, 180, 16) (162, 44, 142)
Cyan (16, 180, 180) (131, 156, 44)
Green (16, 180, 16) (112, 72, 58)
Magenta (180, 16, 180) (84, 184, 198)
Red (180, 16, 16) (65, 100, 212)
Blue (16, 16, 180) (35, 212, 114)
Black (16, 16, 16) (16, 128, 128)

The Test Pattern Generator II IP core can optionally add a black border around the edge of the color bars test pattern. The black border is 2 pixels wide or deep and, if run-time control enabled, you can enable or disable the border at run time.

Each color bar is approximately 1/8th of the width of the output frame, but this width is not exact. The actual width of each color bar is affected by the width and the horizontal subsampling .

  • When the output is horizontally subsampled, the pixel-width of each color bar is a multiple of two.
  • When the width of the image (excluding the left and right borders) cannot be exactly divided by eight, then the last black bar is larger than the others.

For example, when producing a 640×480 frame in the Y’CbCr color space with 4:2:2 subsampling, the left and right black borders are two pixels wide each, the seven initial color bars are 78 pixels wide ((640–4)/8 truncated down to the nearest multiple of 2) and the final black color bar is 90 pixels wide (640–7×78–4).