Over the past decade several video coding technologies
have emerged to achieve great commercial success and it is widely expected that
digital video systems will completely replace all existing traditional analogue
based video systems during the next decade. DISCOVER will address the
development of several advanced digital video coding technologies which are
very likely to represent a breakthrough in new video coding application
scenarios.
Until now video coding research and standardization
have been adopting a video coding paradigm where it is the task of the encoder
to explore the source statistics, leading to a complexity balance where complex
encoders interact with simpler decoders. This paradigm is strongly dominated
and determined by applications such as broadcasting, video on demand, and video
streaming. Distributed Video Coding (DVC) adopts a completely different coding
paradigm by giving the decoder the task to exploit - partly or wholly - the
source statistics to achieve efficient compression. This change of paradigm
also moves the encoder-decoder complexity balance, allowing the provision of
efficient compression solutions with simple encoders and complex decoders.
This new coding paradigm, never considered by any
video coding standard, is particularly adequate to emerging applications such
as wireless video cameras and wireless low-power surveillance networks, disposable
video cameras, certain medical applications, sensor networks, multi-view image
acquisition, networked camcorders, etc., where low complexity encoders are a
must because memory, computational power, and energy are scarce.
The objective of DISCOVER is to explore and propose new video coding schemes and tools in the area of Distributed Video Coding with a strong potential for new applications, targeting new advances in coding efficiency, error resiliency, scalability, and model based-video coding thus paving the way for a breakthrough regarding the next video coding generation.
DVC is based on the Slepian-Wolf and Wyner-Ziv theorems. These theorems state that it is possible to compress two statistically dependent signals in a distributed way (separate encoding, jointly decoding) using a rate equal to that used in a system where the signals are encoded and decoded together.
Current approaches mostly implement the unsymmetrical case, where the two signals are coded with different bitrates.
The block diagram of the architecture used in DISCOVER is shown in Figure 1.
