Rate-distortion optimized mode selection for very low bit rate video coding and the emerging H.263 standard

T. Wiegand, M. Lightstone, D. Mukherjee, T.G. Campbell, S.K. Mitra
1996 IEEE transactions on circuits and systems for video technology (Print)  
This paper addresses the problem of encoder optimization in a macroblock-based multi-mode video compression system. An e cient solution is proposed in which, for a given image region, the optimum combination of macroblock modes and the associated mode parameters are jointly selected so as to minimize the overall distortion for a given bit-rate budget. Conditions for optimizing the encoder operation are derived within a rate-constrained product code framework using a Lagrangian formulation. The
more » ... nstantaneous rate of the encoder is controlled by a single Lagrange multiplier that makes the method amenable to mobile wireless networks with time-varying capacity. When rate and distortion dependencies are introduced between adjacent blocks as is the case when the motion vectors are di erentially encoded and or overlapped block motion compensation is employed, the ensuing encoder complexity is surmounted using dynamic programming. Due to the generic nature of the algorithm, it can be successfully applied to the problem of encoder control in numerous video coding standards, including H.261, MPEG-1, and MPEG-2. Moreover, the strategy is especially relevant for very low bit rate coding over wireless communication channels where the low dimensionality of the images associated with these bit rates makes real-time implementation very feasible. Accordingly, in this paper the method is successfully applied to the emerging H.263 video coding standard with excellent results at rates as low as 8.0 Kbits per second. Direct comparisons with the H.263 test model, TMN5, demonstrate that gains in PSNR are achievable over a wide range of rates. 2
doi:10.1109/76.488825 fatcat:37hzeywpizcnpgjjwxduq4fvza