Luma-based chroma intra-prediction for video coding

A method for luma-based chroma intra-prediction in a video encoder or a video decoder is provided that includes down sampling a first reconstructed luma block of a largest coding unit (LCU), computing parameters α and β of a linear model using immediate top neighboring reconstructed luma samples and left neighboring reconstructed luma samples of the first reconstructed luma block and reconstructed neighboring chroma samples of a chroma block corresponding to the first reconstructed luma block, wherein the linear model is PredC[x,y]=α·RecL′[x,y]+β, wherein x and y are sample coordinates, PredC is predicted chroma samples, and RecL′ is samples of the down sampled first reconstructed luma block, and wherein the immediate top neighboring reconstructed luma samples are the only top neighboring reconstructed luma samples used, and computing samples of a first predicted chroma block from corresponding samples of the down sampled first reconstructed luma block using the linear model and the parameters.