Information hiding in AVS compressed stream

This paper presents a novel information hiding algorithm for AVS (audio video coding standard), taking advantage of the specific features of this self developed Chinese audio video compression standard. AVS adopts Exp-Golomb coding and context based adaptive variable length coding to solve the entropy coding problem, almost all the syntax elements are encoded using Exp-Golomb codes. In the compressed bitstream, hidden bits are embedded by modulating the corresponding Exp-Golomb code, which is based on the mapping rules between these codes and the hidden bits. The hiding positions are limited to maintain the quality of the reconstructed images. Hidden information can be retrieved by decoding the Exp-Golomb code from bitstream, requiring neither original media nor complete video decoding. The experimental results show that the hidden algorithm has little effect on the video quality and the bitrate hasnpsilat been changed.