Limiting the Effect to Specific Channels

Parameters in this group allow you to limit the output of the effect to specific channels.

Blur applied to all channels (left), to the blue channel (center) and to Chroma only (right)

Blur applied to all channels (left), to the blue channel (center) and to Chroma only (right)

The Select parameter allows you to control the amount each channel should be affected, in a number of color spaces:

  • All: all color information contributes to the output.
  • RGB: mix different amounts of red, green and blue channels.
  • HSB: mix different amounts of hue, saturation and brightness.
  • CMYK: mix different amounts of cyan, magenta, yellow and black channels (subtractive primaries common in printing).
  • YUV: mix different amounts of luminance and chroma channels. Colors are represented according to the Y’CbCr standard used in broadcast video.
  • Oklab: mix different amounts of lightness and color along the blue/yellow or green/red gradients, as defined by the Oklab perceptual color space.
When selecting All channels, a single Mix slider allows you to mix the filtered output with the original, unfiltered image, using a perceptual method. When selecting any other color space, separate Mix 1, Mix 2 and Mix 3 sliders allow you to mix the corresponding channel. When processing your output in CMYK, a separate Mix 4 slider is also available and affects the Black channel.

When any Mix slider is set to 100%, color information for the corresponding channel comes exclusively from the filtered output. When set to 0%, information comes exclusively from the original (unfiltered) media. Values in between allow you to blend the unfiltered media with the output of the effect.

What happens to the Alpha channel?

As you mix color information between the original video frame and the output of the effect, the Alpha parameter allows you to define how the alpha channel is calculated:

  • Blend: an average of the original alpha and the one generated by the effect is used.
  • Foreground: only the alpha channel from the effect is used.
  • Background: only the alpha channel from the original video frame is used.
  • Min: the minimum of the two alpha channels is used.
  • Max: the maximum of the two alpha channels is used.
If your effect has a Build In/Out animation, it will influence the channel mixing process too.