Rate control for unbalanced multiple description video streaming

Unbalanced multiple description coding (U-MDC) of video signals aims to obtain different coding rates for transmission over channels with asymmetric available bandwidth. This paper proposes a new rate control method, based on Multiple Description Scalar Quantisation (MDSQ), to generate unbalanced descriptions for asymmetric multipath video streaming. A new set of index assignment tables combined with an extension of the ρ model is devised to generate two unbalanced descriptions with controlled rate, using U-MDC under the general coding framework of H.264/AVC. This work demonstrates that a linear relationship between the rate and percentage of zeros in the transform coefficients of each description is maintained across different description domains, i.e., when moving from the single description domain (SDC) into the MDC domain. The simulation results show that rate-distortion performance of U-MDC is better than its equivalent balanced MDC. The proposed rate control algorithm exhibits high accuracy in achieving different target bitrates and unbalanced ratios between two descriptions. Improved performance is also achieved in video streaming over asymmetric transmission paths, where each description rate can be adapted according to different channel conditions.