Baochun Bai

An Efficient Multiview Video Compression Scheme

Multiview video compression is important to the image-based 3D video applications. In this paper, we proposes a novel neighbor-based multiview video compression scheme. It is essentially a MPEG2-like block-based scheme. In particular, a method to decide the stream encoding order is presented. The resulting stream encoding order can better decorrelate spatial redundancies among multiple video streams than the center approach. Experimental results confirm the superiority of the proposed neighbor approach over the center approach and MPEG2 for multiview video compression

A multiview video transcoder

Video transcoding can convert a compressed video from one format to another format. In this paper, we propose a novel multiview video transcoder, which is used for bit-rate scaling of multiple compressed synchronized video streams. Different from the traditional joint transcoder for independent multiple program transcoding, the multiview video transcoder has one unique task to decorrelate spatial redundancies among video streams. A fast disparity estimation algorithm with the GOP-based disparity search window is put forward and evaluated. The proposed multiview video transcoder can be used to design a cost-effective video acquisition and transmission system for emerging 3D video applications.

Stable and robust multipath oblivious routing for traffic engineering

Intra-domain traffic engineering is essential for the operation of an Internet Service Provider. Demand-oblivious routing [2] promises excellent performance guarantee with changing and uncertain traffic demands. However, it is difficult to implement it. We investigate an efficient and deployable implementation of oblivious routing. We study its performance by both numerical experiments and simulation. The performance study shows that the multipath implementation achieves a close approximation to oblivious routing [2], especially when approximate knowledge of traffic is available. The study also shows its robustness under varying traffic demands, link failures and an adversary attack. Its performance is excellent even with a 100% error in traffic estimation.

Symmetric Distributed Source Coding using LDPC Code

Distributed source coding is a promising enabling technology for sensor network applications. Symmetric distributed source coding can achieve the entire Slepian-Wolf rate region and offer sensor network applications a wide range of options to compress and transmit data. In this paper, we design a new symmetric distributed coding scheme that realize the benefits of both simplified code construction and bit incorrespondence handling. In particular, we propose a general scheme to deal with the bit incorrespondence problem, which is not specifically addressed by previous approaches. With the ability to deal with the bit incorrespondence in the code structure, it is more likely for our approach to be used in real sensor network environments.

Multipath Oblivious Routing for Traffic Engineering - Stable and Robust Routing in Changing and Uncertain Environments

Intra-domain traffic engineering is essential for the operation of an Internet Service Provider (ISP). Demandoblivious routing [5] promises excellent performance guarantee with changing and uncertain traffic demands. However, it is non-trivial to implement it. We investigate an efficient and deployable implementation of oblivious routing. We study its performance by both numerical experiments and simulation. The performance study shows that the multipath implementation achieves a close approximation to oblivious routing [5], especially when approximate knowledge of traffic is available. The study shows its robustness under varying traffic demands, link failures and an adversary attack. Its performance is excellent even with a 100% error in traffic estimation. We open the door for a deployable demand-oblivious routing, which can provide robust network services with good quality to network users.

Active error recovery for reliable multicast

An error recovery scheme is essential for large-scale reliable multicast. We design, implement, and evaluate an improved active error recovery scheme for reliable multicast (AERM). The AERM uses soft-state storage to facilitate fast error recovery. It has the following features: a simple NAK suppression and aggregation mechanism, an efficient hierarchical RTT measurement mechanism, an effective local recovery and scoped retransmission mechanism, and a periodical ACK mechanism. We implement the AERM and study its characteristics in NS2. We also compare performance with ARM and AER/NCA, both of which are representative active reliable multicast protocols. The results indicate that AERM can achieve considerable performance improvement with limited support from routers. Our work also confirms that active networks can benefit some applications and become a promising network computing platform in the future.

Learning-based multiview video coding

In the past decade, machine learning techniques have made great progress. Inspired by the recent advancement on semi-supervised learning techniques, we propose a novel learning-based multiview video compression framework. Our scheme can efficiently compress the multiview video represented by multiview-video-plus-depth (MVD) format.We model the multiview video compression problem as a semi-supervised learning problem and design sophisticated mechanisms to achieve high compression efficiency. Our approach is significantly different from the traditional hybrid coding scheme such as H.264-based multiview video coding methods. The preliminary results show promising compression performance.

Symmetric distributed multiview video coding

Symmetric distributed source coding has made great progress in the past several years. However, few attempts have been tried to use the symmetric distributed source coding schemes in real data compression scenarios. In this paper, with the inspiration of previous symmetric distributed source coding schemes, we first put forward a novel syndrome-based symmetric distributed coding scheme which can achieve the whole Slepian-Wolf rate region. Then we propose a general architecture for symmetric distributed multiview video schemes. Our experiments show very encouraging results. In the high-rate case, our scheme can achieve great rate saving from separate H.264 coding scheme at the same video quality.

An efficient scheme for QoS information update among edge routers using multicast

It is essential and nontrivial to disseminate QoS information in an efficient manner and to guarantee the information accuracy. We present an efficient scheme for QoS information update among edge routers in a diffserv region. In our scheme, a multicast tree is constructed among the edge routers in a diffserv region to transmit the updates. This scheme is efficient in consuming network resources since the cost for QoS information update of using a tree is much less than using a flooding approach, and routers unrelated to decision-making are relieved from disseminating and storing QoS information. In addition, it is easy to implement our scheme in the Internet, since only edge routers need to deploy it. We investigate quantitatively the cost of our scheme for QoS information update against a flooding approach and study empirically the efficiency of several proposed QoS information update policies.