Wavelet transform-based downsampling for low bit-rate video coding

摘要

Video coding has been a very hot area of research for a long time. The latest standard High Efficiency Video Coding (HEVC) outperforms H.264 a lot and needs only half of bit-rate to obtain the same performance. However HEVC is designed for high definition video such as 1080p and above. The high compression rate calls for high complexity, which limits the application in some low bandwidth and low complexity conditions. In this paper, an idea of wavelet transform-based downsampling scheme for intra mode is used before HEVC coding to ensure the bandwidth for low frequency content of video in low bit-rate condition. Furthermore the downsampled size of video can reduce the complexity of HEVC encoding procedure to only a quarter of the original size. To make the performance better, we also allocate bandwidth for high frequency content. Bit-plane encoding with frame partition is used to encode the high frequency coefficients efficiently. Bit-plane encoding scheme encodes big data first so that the high frequency content can be transmitted in an arbitrary truncated bitstream. Frame partition uses fewer bits to encode more coefficients. Simulation results of intra mode coding are presented to show the advantage of our algorithm. The proposed wavelet transform-based downsampling scheme reduces the complexity of HEVC. Together with high frequency coefficients encoding, our algorithm can perform similar coding performance as HEVC.