# Chroma

| Message                 | Description                                                                                                                                                                                        | Arguments |
| ----------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------- |
| `/mixeffect/usk/chroma` | Sets the Chroma upstream keyer. This is available on certain, older ATEM switchers such as the ATEM 1 M/E Production Studio 4K, ATEM Television Studio HD, and the ATEM 4 M/E Broadcast Studio 4K. | Multiple  |

| Argument  | Type    | Description                                          |
| --------- | ------- | ---------------------------------------------------- |
| Hue       | Float   | Float from 0 to 360.0.                               |
| Gain      | Float   | Float from 0 to 100.0.                               |
| ySuppress | Float   | Float from 0 to 100.0.                               |
| Lift      | Float   | Float from 0 to 100.0.                               |
| Narrow    | Integer | <p>0 = False<br>1 = True</p>                         |
| 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. |