> For the complete documentation index, see [llms.txt](https://docs.mixeffect.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mixeffect.app/automate/osc/messages/upstream-keyers/chroma-parameter-set.md).

# Chroma Parameter Set

| Message                               | Description                                           | Arguments |
| ------------------------------------- | ----------------------------------------------------- | --------- |
| `/mixeffect/usk/chroma/parameter/set` | Sets a single legacy Chroma upstream keyer parameter. | Multiple  |

| Argument  | Type    | Description                                                      |
| --------- | ------- | ---------------------------------------------------------------- |
| Parameter | Integer | <p>0 = hue<br>1 = gain<br>2 = ySuppress Edge<br>3 = Lift<br></p> |
| New Value | Float   | The new value.                                                   |
| USK       | Integer | One-based index of the Upstream Keyer. Default is 1.             |
| M/E       | Integer | One-based index of the Mix Effect Bus. Default is 1.             |