Hybrid multiple description video coding using optimal DCT coefficient splitting and SD/MD switching

摘要

This paper proposes a robust video transmission algorithm, which is based on the multiple description coding (MDC) scheme that optimally splits DCT coefficients, and also proposes a switching algorithm for the optimal operation of the encoder between the single description (SD) and multiple description (MD) mode under the given packet loss rate (PLR). In the proposed MDC algorithm, DCT coefficients are either duplicated to every stream or alternated to one of streams, which is decided by the rate-distortion (RD) optimization process. The optimization problem is formulated by modifying the DCT coefficient thresholding algorithm, which can be solved by dynamic programming. Although the MD coding is more resilient than the SD coding in the severe PLR condition, its excessive redundancy results in degraded RD performance in the low PLR. To increase the scalability of MDC, we propose the SD/MD switching method, which uses the SDC for the coding efficiency in the low PLR, and MDC for the error resilience in the high PLR. An RD optimization based strategy is proposed for optimal switching under the given channel condition. Since the decoder distortion is necessary to estimate RD cost function at the time of encoding, we adopt the recursive optimal per-pixel estimate (ROPE) technique. Experimental results show that the optimal combination of the optimal split of DCT coefficients and the SD/MD switching provides higher PSNR than the conventional error resilient methods based on the inter/intra switching in low PLR conditions as well as in high PLR.