1. A method for encoding video data, the method comprising: classifying at least one macroblock of at least one original reference picture with a circuit; estimating an amount of data for encoding the at least one macroblock, in parallel, based on the macroblock classification; generating a target rate for encoding the at least one macroblock based on the respective estimated amount of data for the at least one macroblock; and selecting, based on the target rate or the macroblock classification, at least one quantization parameter for the at least one macroblock of the at least one original reference picture.