Rate Distortion Data Hiding of Motion Vector Competition Information in Chroma and Luma Samples for Video Compression

New standardization activities have been recently launched by the JCT-VC experts group in order to challenge the current video compression standard H.264/AVC. Several improvements of this standard, previously integrated in the JM key technical area software, are already known and gathered in the high efficiency video coding test model. In particular, competition-based motion vector prediction has proved its efficiency. However, the targeted 50% bitrate saving for equivalent quality is not yet achieved. In this context, this paper proposes to reduce the signaling information resulting from this motion vector competition, by using data hiding techniques. As data hiding and video compression traditionally have contradictory goals, an advanced study of data hiding schemes is first performed. Then, an original way of using data hiding for video compression is proposed. The main idea of this paper is to hide the competition index into appropriately selected chroma and luma transform coefficients. To minimize the prediction errors, the transform coefficients modification is performed via a rate-distortion optimization. The proposed scheme is evaluated on several low and high resolution sequences. Objective improvements (up to 2.40% bitrate saving) and subjective assessment of the chroma loss are reported.

I. Introduction

Significant compression gain, compared to former video coding standards, has been achieved by the ITU-T SG16-Q6 H.264 standard of the video coding experts group (VCEG), also known as ISO/IEC JTC 1/SC 29/WG 11 MPEG-4 AVC [1] of the moving picture experts group (MPEG). This gain results from the improvement of existing tools and the inclusion of new ones. These improvements concern the motion estimation and the information coding with context adaptive binary arithmetic coding (CABAC), and above all the addition of several Intra and Inter modes with many encoding methods which need the transmission of competition signalization indices.