Distributed Low-Complexity H.264 Video Combining for Multipoint Video Conferencing

In this paper we propose a distributed video combining method applicable to continuous presence multipoint video conferencing for the H.264 coding standard. The proposed method takes advantage of the significant coding features of the H.264 format and employs star-connected multiple video combiners to perform combining process cooperatively. We investigate the architecture and the required operations of the proposed distributed H.264 video combining. The edge combiner receives the input video streams of partial conferencing participants and combines them into a combined video sub-stream conforming to some particular requirements using some fast algorithms by reusing decoded information as reference for re-encoding. The central combiner receives the combined sub-streams of the edge combiners and combines them into a final combined stream. The central combiner operates in the coded-domain and performs only a few simple changes in the header data. Essential details for implementing the proposed method are presented, along with simulation results for validating it.