1. A method for chroma intra prediction for a current chroma block, wherein chroma intra predictor is derived from reconstructed luma pixels of a current luma block using a model with parameters, the method comprising: receiving a reconstructed luma pixel set corresponding to neighboring reconstructed luma pixels from causal luma neighboring areas of the current luma block, wherein said causal luma neighboring areas comprise a first area corresponding to reconstructed luma pixels above a horizontal luma block boundary on a top side of the current luma block, and wherein the reconstructed luma pixels from the first area that are included in the reconstructed luma pixel set are from a luma pixel line immediately above the horizontal luma block boundary; receiving a reconstructed chroma pixel set corresponding to neighboring reconstructed chroma pixels from causal chroma neighboring areas of the current chroma block; deriving the parameters based on said reconstructed luma pixel set and said reconstructed chroma pixel set; and generating the chroma intra predictor for chroma pixels to be predicted in the current chroma block based on the reconstructed luma pixels of the current luma block using the model with the parameters derived.