A second-order-residual (SOR) coding approach to high-bit-rate video compression

A novel video compression scheme that exploits the idea of second-order-residual (SOR) coding is proposed for high-bit-rate video applications in this work. We first study the limitation of today's high performance video coding standard, H.264/AVC, and show that it is not effective in the coding of small image features and variations for high-bit-rate video contents. For low to medium quality video streams, these small image features can be removed by the quantization process. However, when the quantization stepsize becomes small in high-bit-rate video, their existence degrades the rate-distortion coding performance significantly. To address this problem, we propose a coding scheme that decomposes the residual signals into two layers: the first-order-residual (FOR) and the second-order-residual (SOR). The FOR contains low frequency residuals while the SOR contains the high frequency residuals. We adopt the H.264/AVC for the FOR coding and propose two schemes, called SOR-freq and SOR-bp, for the SOR coding. It is shown by experimental results that the proposed FOR/SOR scheme outperforms H.264/AVC by a significant margin (with about 20% bit rate saving) in high-bit-rate video.