A video coder determines a boundary luma value and derives a chroma value that corresponds to the boundary luma value. The video coder may derive a first prediction model and a second prediction model based on the derived chroma value. The video coder may use the first prediction model to determine a first set of predicted chroma samples of a prediction block for the current block. The first set of predicted chroma samples corresponds to the luma samples of the prediction block that have values less than or equal to the boundary luma value. The video coder may use the second prediction model to determine a second set of predicted chroma samples of the prediction block. The second set of predicted chroma samples corresponds to the luma samples of the prediction block that have values greater than the boundary luma value.