A Parallel ANS Coder with Reduced Decoding Error Diffusion

The Asymmetrical Numeral Systems (ANS) coding has received significant attention in well-integrated compression systems. One particularly insightful technique that has emerged is the interleaved ANS coder (IAC), which substantially enhances the throughput by using multiple encoders and decoders. However, IAC has a limitation that even a single bit error in the compressed bitstream may diffuse across multiple decoders, resulting in many symbols to be incorrectly decoded. In this paper, we propose a parallel method to mitigate the diffusion for a class of error patterns, by limiting the errors to affect only a single decoder. The simulation results show that compared with IAC, our proposal can reduce the average number of incorrectly decoded symbols by about 50% while maintaining comparable encoding and decoding throughput.