A block processing pipeline in which macroblocks are input to and processed according to row groups so that adjacent macroblocks on a row are not concurrently at adjacent stages of the pipeline. The input method may allow chroma processing to be postponed until after luma processing. One or more upstream stages of the pipeline may process luma elements of each macroblock to generate luma results such as a best mode for processing the luma elements. Luma results may be provided to one or more downstream stages of the pipeline that process chroma elements of each macroblock. The luma results may be used to determine processing of the chroma elements. For example, if the best mode for luma is an intra-frame mode, then a chroma processing stage may determine a best intra-frame mode for chroma and reconstruct the chroma elements according to the best chroma intra-frame mode.