Murat B. Badem

An iterative side information refinement technique for transform domain Distributed Video Coding

Distributed Video Coding (DVC), has been an interesting alternative to the conventional video coding for a number of applications because of its flexibility for designing extremely low complexity video encoders. The performance of DVC can be improved by only modifying the decoder to keep the encoder complexity at the same level. In this paper, we propose a novel modified framework for a DVC codec considering an iterative side information refinement technique. Refinement is performed at the decoder, first with the help of the decoded DC frame and then considering partially decoded frame using previously refined side information. By iteratively refining the side information, a significant improvement has been achieved in the rate distortion performance.

Transform domain distributed video coding with spatial correlations

Distributed Video Coding is a new coding technique which has been evolving very fast recently. However the rate distortion performances of current solutions are below the expectations especially for high motion sequences even at a group of picture (GOP) size of 2. Main reason of this problem is the temporal prediction of the Wyner-Ziv (WZ) frames at the decoder. In this paper we propose a novel transform domain DVC codec architecture which splits each frame into two sub-frames and they are encoded separately as key sub-frame and WZ sub-frame. Pixel interpolation or median prediction techniques are utilized to generate the side information at the decoder. Simulation results show that a significant rate distortion improvement can be obtained with the proposed algorithm over the current DVC solutions.

Unidirectional Distributed Video Coding using dynamic parity allocation and improved reconstruction

Distributed Video Coding (DVC), has been an attractive alternative to the conventional video coding for a number of applications because of its flexibility for designing extremely low complex video encoders. DVC based video codecs proposed in the literature generally include a dynamic feedback channel between the encoder and the decoder. However it is observed that this dynamic feedback mechanism is a practical hindrance in a number of practical consumer electronics applications. In this paper, a novel transform domain Unidirectional Distributed Video Codec (UDVC) without a feedback channel is proposed. A simple encoder rate control algorithm is used in order to eliminate the feedback channel of the existing DVC codecs while keeping the encoder complexity as low as possible. Moreover, an improved reconstruction algorithm is utilised in order to improve the quality of the reconstructed frame. Simulation results show that the performance of the proposed codec can approach to that of DVC with feedback, which is assumed to be known as the upper bound.

Region-of-Activity Based Coding for Transform Domain DVC

Distributed video coding (DVC) has been widely acclaimed as an emerging video coding technology with immense potential for use in video surveillance systems due to its flexibility for designing extremely low complex video encoders. In this paper, we propose a novel modified framework for the DVC codec considering a region-of-activity based coding algorithm. The frames will be split into a sequence of regions based on the activity level that reflect the error distribution in the side information. The macro blocks will be re-ordered to concatenate the unevenly distributed errors and form new blocks for turbo coding to improve the efficiency of the puncturing process. The performance of the proposed technique is verified for three standard test video sequences and up to 21% bit rate saving is demonstrated.

Quality Analysis of Side Information Refinement in Transform-Based DVC

Distributed video coding (DVC) has been proposed for different new application domains. This rise is apparently motivated by the very attractive features of its flexibility for building very low cost video encoders and the very high built-in error resilience when applied over noisy communication channels. These features could be very effectively exploited in several application domains including wireless sensor networks for security surveillance and mobile video communications. So far DVC has used PSNR to measure the quality of the decoded video. In this paper, we analyze the performance of the DVC encoded video with three different quality matrices: PSNR, VQM and SSIM. We used one of our side information refinement algorithms in transform domain DVC as the basis for all comparisons. Simulation results show that the side information refinement technique based on motion analysis can achieve a significant coding gain with respective to all quality matrices considered. However, subjective results show that VQM has a very high correlation with the MOS which suggests that VQM is a better quality metric that can be used in DVC.