Model-based rate allocation in distributed video coding systems

In distributed video coding (DVC) systems the rate control is usually performed at the decoder through a feedback channel. However, a feedback channel incurs a delay and might be impractical for real-time applications. Typically, systems that suppress feedback use a fixed uniform quantization across the entire frame, regardless of its local characteristics. In this work a framework for intraframe rate allocation at the encoder side is suggested as a way to both suppress the feedback channel and adapt the quantization to the frame characteristics. The rate allocation utilizes an approximation model to the rate-distortion function for Laplacian data and correlation channel distributions. This model replaces an analytical solution given in integral form that can be evaluated only numerically. A practical DVC system that is based on this scheme is proposed. The use of intraframe rate allocation is indeed found to improve the performance of the feedback-less system.