Distributed video coding: Basics, main solutions and trends

Abstract

After the great success of the predictive video coding approach, which led to a number of largely deployed MPEG and ITU-T standards, the video coding research community has been working on a new video coding paradigm, so-called distributed video coding (DVC), which is based on some Information Theory results from the 70s: the Slepian-Wolf and the Wyner-Ziv theorems. The first practical solutions have emerged around 2002 at the Stanford University and the University of California, Berkeley. This talk will address the basics, main solutions and trends on distributed video coding with especial emphasis on the Stanford DVC codec which has deserved a larger research investment. The rate-distortion (RD) performance of a state-ofthe-art Stanford based DVC codec will be presented and benchmarked by the relevant alternative standard based video coding solutions. Finally, some trends on the DVC research will be discussed.Index Terms -distributed video coding, Wyner-Ziv video coding, RD performance THE BASICSWith the wide deployment of mobile and wireless networks, there are a growing number of applications where many senders deliver data to a central receiver. Contrary to television like applications, these emerging applications typically require light encoding complexity while still requiring high compression efficiency, robustness to packet losses and, often, also low latency/delay. To address these emerging needs, some research groups revisited the video coding problem at the light of some Information Theory results from the 70s: the Slepian-Wolf and the Wyner-Ziv theorems [1,2]. According to the Slepian-Wolf theorem, the minimum rate needed to independently encode two statistically dependent discrete random sequences, X and Y, is the same as for joint encoding. Moreover, under some hypothesis on the joint statistics, the Wyner-Ziv theorem [2] adds that when the side information (i.e. the correlated source Y) is made available only at the decoder there is no coding efficiency loss in lossy encoding X, with respect to the case when joint encoding of X and Y is performed. Together, the Slepian-Wolf and the Wyner-Ziv theorems suggest that it is possible to encode two statistically dependent signals independently and decoding them jointly, while approaching the coding efficiency of conventional predictive coding schemes, which rely instead on joint encoding and decoding. The new coding approach, known as Distributed Video Coding (DVC), avoids the computationally intensive temporal prediction loop at the encoder, by shifting the exploitation of the temporal redundancy to the decoder. This may be a significant advantage for a large range of emerging application scenarios, including wireless video cameras, wireless low-power surveillance, and visual sensor networks. Based on the theoretical foundations above and following important developments in channel coding technology, the practical design of Wyner-Ziv (WZ) video codecs, a particular case of DVC related to lossy coding with side information available at the decoder, start...

Distributed multi-hypothesis coding of depth maps using texture motion information and optical flow

“…In this work we address the coding of depth maps, using DVC [1,2] as basis of our coding architecture.…”

Wyner-Ziv coding of depth maps exploiting color motion information

“…Recent advances show that Distributed Video Coding (DVC) is becoming a feasible alternative to traditional video coding in scenarios in which the encoding complexity is limited by strict constraints 1,2 . A typical scenario is multi-camera video surveillance, in which power consumption constraints require low-complexity encoders while complexity constraints are relaxed at the decoder side.…”

Adaptive Motion Vector Smoothing for Improving Side Information in Distributed Video Coding

“…The DIStributed COding for Video sERvices (DISCOVER) codec is also a frame-based architecture, but improves the Stanford codec in Side Information (SI) generation, reconstruction, channel coding and so on. In [7], the rate-distortion performance of these codecs has been discussed.…”