Wyner-Ziv video coding for wireless lightweight multimedia applications

Abstract

Wireless video communications promote promising opportunities involving commercial applications on a grand scale as well as highly specialized niche markets. In this regard, the design of efficient video coding systems, meeting such key requirements as low power, mobility and low complexity, is a challenging problem. The solution can be found in fundamental information theoretic results, which gave rise to the distributed video coding (DVC) paradigm, under which lightweight video encoding schemes can be engineered. This article presents a new hashbased DVC architecture incorporating a novel motion-compensated multi-hypothesis prediction technique. The presented method is able to adapt to the regional variations in temporal correlation in a frame. The proposed codec enables scalable Wyner-Ziv video coding and provides state-of-the-art distributed video compression performance. The key novelty of this article is the expansion of the application domain of DVC from conventional video material to medical imaging. Wireless capsule endoscopy in particular, which is essentially wireless video recording in a pill, is proven to be an important application field. The low complexity encoding characteristics, the ability of the novel motion-compensated multi-hypothesis prediction technique to adapt to regional degrees of temporal correlation (which is of crucial importance in the context of endoscopic video content), and the high compression performance make the proposed distributed video codec a strong candidate for future lightweight (medical) imaging applications.

Encoder-driven rate control and mode decision for distributed video coding

“…Regarding the performance on Foreman, shown in Figure 7, the compression performance of the proposed feedback-channel-free architecture is roughly comparable to the performance of DISCOVER, H.264/AVC Intra and the hash-based system from [7] for a GOP of 2. Amongst these, the DVC systems slightly outperform H.264/AVC Intra at low rates but lag somewhat behind at the highest rates.…”

“…The experimental results presented in this work, however, show the benefit of the different coding modes available to the proposed system and clarify their influence on the compression performance. Additionally, the compression performance of the proposed feedback-channel-free DVC architecture is compared to the benchmark systems in DVC, that is, the DISCOVER codec [13] and H.264/AVC Intra [35], as well as our previous hashbased DVC system with feedback from [7]. In addition, compression results obtained using the proposed system including the presented mode decision process but configured with decoder-driven feedback-channel-based rate allocation are included as well.…”

“…The compression performance of the proposed feedback-free architecture with all three coding modes activated is benchmarked against the feedback-channelbased DISCOVER [13] codec, as well as H.264/AVC Intra [35]. In addition, compression results obtained with our previous hash-based DVC architecture from [7] are also included. The system generates SI by means of hash-based OBMEC, where the original WZ frames are downscaled and subsequently coded using H.264/AVC Intra coding at low bit-rate to create the hash information.…”

“…from [7] and the proposed system with feedback, is given in Table 4. Regarding the performance on Foreman, shown in Figure 7, the compression performance of the proposed feedback-channel-free architecture is roughly comparable to the performance of DISCOVER, H.264/AVC Intra and the hash-based system from [7] for a GOP of 2.…”

“…As a result, DVC targets lightweight multimedia applications [6], e.g. wireless capsule endoscopy [7,8].…”