A High Capacity HEVC Steganographic Algorithm Using Intra Prediction Modes in Multi-sized Prediction Blocks

Abstract

The existing video steganographic schemes based on intra prediction modes for video coding standards H.264/AVC and HEVC all use single-sized blocks to embed the secret payload. Thus, the steganographic properties of HEVC multi-sized tree-structured intra partition still need exploration. In this paper, a novel video steganographic algorithm is presented. Base on the fact that visual quality degradation caused by steganography is basically the same for both large-sized Prediction Blocks (PBs) and small-sized PBs, this algorithm tries to exploit intra prediction modes in multi-sized PBs in each Coding Tree Units (CTU). The innovation of this paper includes: (1) Improvement in capacity without introducing great degradation in visual quality. (2) High coding efficiency maintained by defining cost function based on rate distortion. (3) A new indicator to measure Bit Increase Ratio(BIR) under different capacity. The Experimental results show that this algorithm outperforms the latest intra prediction modes based HEVC steganographic algorithm in both capacity and perceptibility while preserving coding efficiency as well.