In this paper we present two optimum (in a rate-distortion ? RD ? sense) rate-control algorithms for FGS scalable video. The proposed methods, which could compliment recently proposed RD FGS algorithms for bit allocation among different FGS frames, are targeted for optimum rate allocation among the different macroblock bitplanes within each FGS frame. The proposed methods are also designed to be very low in complexity to enable real-time streaming and fast off-line processing. Simulations with a variety of video sequences have been conducted and some of these simulations are presented in this paper. Based on these results, the proposed RD based ratecontrol algorithms provide a gain of 0.25 ? 0.6 dB gain when compared with the traditional raster-scan bitplane FGS ratecontrol algorithm.