A dual Cauchy rate-distortion model is proposed for video coding. In our approach, the coefficient distribution of the integer transform is first studied. Then, based on the observation that the rate-distortion model of the luminance and that of the chrominance can be well expressed by separate Cauchy functions, a dual Cauchy rate-distortion model is presented. Furthermore, the simplified rate-distortion formulas are deduced to reduce the computational complexity of the proposed model without losing the accuracy. Experimental results have shown that the proposed model is better able to approximate the actual rate-distortion curve for various sequences with different motion activities.
A novel Multiple Description Coding method, named Packeted Multiple Description Coding (PMDC) is presented in this paper. First, we separate the wavelet transformed image into several sub-images and code each sub-image by a method called Unequal Loss Protected Multiple Description Subband Coding (ULPMDC). With this algorithm, we can first form two sub-descriptions, which contain packets from the image, and then we transmit them by two different channels. If no more than one sub-description per sub-image is lost, the proposed algorithm will get very good reconstruction quality. If more sub-descriptions per sub-image are lost, the reconstruction quality is severely degraded. To provide better quality of the reconstructed image, we then modify the packetizing process, and propose a novel packetized MDC framework, named Cross Packetized Multiple Description Coding (CPMDC). In this method, instead of applying ULPMDC on sub-images, we first code the whole image into two descriptions. Then we split each description horizontally and vertically to form row packets and column packets, respectively. The simulation results show that if only some row packets or column packets are lost, the reconstruction quality is still as good as the former scheme. If we lose both columns and rows, CPMDC will still be better than PTSQ.
The goal of this paper is to design a TCP friendly real-time video transport protocol that will not only utilize network resource efficiently, but also prevent network congestion from the real-time video transmitting effectively. To this end, we proposed a source based congestion control scheme to adapt video coding rate to the channel capacity of the IP network, including three stages: rate control, rate-adaptive video encoding, and rate shaping.