Joe's Filters: Joe's Y/C Corrector

The Joe's Y/C Corrector plugin is a part of Joe's Filters, shareware utility and image processing effects for Final Cut Pro.

What it does

Joe's Y/C Corrector shifts the Chroma or Luma components of a video image. The most common use of this effect is to correct for poor image alignment in analog dubs, but I've found it useful for adjusting some DV footage as well.

Example Images

This detail shows a slip in color of the pepper against the blue background. All the color in the image is drifting to the right, resulting in a blue cast on the left edge and a trailing reddish cast on the right edge. Additionally, the green stem of has a yellow edge and a green shadow.

Using Joe's Y/C Corrector, the color information can be shifted to the left, helping to put the color back where it belongs. This still isn't perfect, partly because of DV's oversized Chroma sampling, but centering the color on the pepper helps to improve the image.

When viewed on a video monitor, this image showed a significant reduction in dot-crawl on the right side of the pepper. When combined with Joe's Channel Blur, tweaking the Chroma resulted in a much cleaner image.

The range of values also allows for more extreme offsetting of the image's color information:

Original Image

Target: Chroma Horizontal: 10

Target: Luma Vertical: -10

Controls

• Target

  Chooses which of the color components to offset.

• Horizontal, Vertical (-10 - 10)

  Determines the amount of offset for the selected color component.

Credits

Thank you to Michael at Pixelmover for suggesting this filter.