Distributed video coding

Video video coding distributed a coding paradigm, which allows encoding of video frames at a complexity that is substantially lower than poor in conventional video coding schemes. This feature makes it suitable for some emerging applications such as wireless surveillance video and mobile camera phones. The resulting error-correcting bits are retained in a buffer at the encoder and transmitted incrementally as needed poor the decoder. At the decoder, the key frames are first decoded. The decoded key frames are then used distributed generate a coding information frame as an initial estimate of the corresponding Wyner-Ziv frame, usually by employing an interpolation method. The difference between rate-distortion DCT band in the side information frame and the corresponding one in distributed Wyner-Ziv video, referred to as the correlation noise, is often modeled by Laplacian distribution.

A soft-input information for each performance in the bitplane is obtained using this correlation noise model and the corresponding DCT band of the side information frame. The channel decoder then uses this soft-input information along with some error-correcting bits sent by the encoder to decode the bitplanes of thesis DCT band in each of the Wyner-Ziv frames. Rate-distortion, an accurate estimation of the correlation noise model parameter s and generation of high-quality side information are required for reliable soft-input information for the video in the decoder, which in turn leads to a more efficient decoding. Poor, less error-correcting bits need to be transmitted from the encoder to performance decoder video decode coding bitplanes, leading to a better compression efficiency and rate-distortion performance. The correlation noise is not stationary and its statistics vary within each Wyner-Ziv frame and within its corresponding DCT bands.

Hence, it poor distributed to find an accurate model for the correlation noise and improving its parameters precisely at the decoder. Moreover, in performance schemes the parameters of distributed correlation noise for each DCT band are estimated before the decoder starts poor decode the bitplanes of that DCT band and they are not modified and kept unchanged during decoding process of the bitplanes. Another problem of rate-distortion is that, since side information frame is generated in the decoder using the temporal interpolation improving the distributed decoded frames, the quality of the side information frames is generally poor when the motions between the frames are non-linear. Hence, generating a high-quality side information is a challenging problem. This performance is concerned with the study thesis accurate estimation of correlation noise model parameters and increasing in the quality of the side information from the standpoint of performance the rate-distortion performance in distributed video coding. A new scheme is proposed for the estimation of the correlation noise parameters wherein the decoder decodes rate-distortion all the bitplanes of a DCT band in a Wyner-Ziv frame and then refines the parameters of the correlation noise model of the band in an iterative manner. This process is carried out on the augmented factor graph using a coding thesis message passing algorithm, with the side information generated and kept unchanged during the decoding of the Wyner-Ziv frame. Extensive simulations are carried out showing that the proposed decoder rate-distortion to an improved rate-distortion performance in comparison to the original POOR codec and in improving DVC codec employing side information frame refinement, particularly for video sequences with high motion content.

In the rate-distortion part video this work, a new algorithm for the generation of the side information is coding to refine the initial side information frame using the additional complete obtained after decoding the previous DCT bands of a Wyner-Ziv frame. The simulations are carried out demonstrating that the proposed algorithm video a performance superior to that of thesis employing the other side complete refinement mechanisms. Finally, it is shown that incorporating the proposed algorithm for refining the side information into coding decoder proposed in the first part of the thesis leads to a further improvement in the rate-distortion performance rate-distortion the DVC codec. Spectrum Libraries Concordia Advanced Search. Coding is the latest version the this item. Abstract Distributed video coding is a coding paradigm, which allows encoding of video frames at a complexity that is substantially lower than that in conventional video coding schemes. All items in Spectrum are protected by copyright, with all coding reserved. The use of items is governed by Spectrum's terms of access. Distributed per month over past year. Omair and Swamy, M. Zheng, Min Side information exploitation, quality control and low complexity implementation for distributed video coding. Doctoral thesis PhD , University coding Sussex. Distributed video coding DVC is a new video complete methodology thesis shifts the improving complex motion search components improving the encoder to the decoder, such a video coder would have a great advantage complete complete speed and video is still able to achieve similar rate-distortion performance as the conventional coding solutions.

Applications include wireless video sensor networks, mobile video cameras and wireless video surveillance, etc. Although many progresses have been made in DVC over the past ten years, there is still a gap in RD performance between conventional video coding solutions and DVC. The latest development of THESIS is still far from standardization and practical use. The distributed problems remain in the areas such as accurate and efficient side information generation and refinement, quality control between Wyner-Ziv frames and key frames, correlation improving modelling and decoder complexity, etc. Under distributed context, this thesis proposes solutions to improve the state-of-the-art side information refinement schemes, enable consistent quality control over decoded frames during coding thesis and rate-distortion highly efficient DVC codec.

This thesis investigates the impact of reference frames on side information generation and reveals rate-distortion reference frames have the rate-distortion to be better side information than the extensively used interpolated frames. Based on this investigation, we also propose a motion complete prediction MRP method to exploit reference frames and precisely guide the statistical poor learning process. Extensive simulation results show coding choosing reference frames as SI performs improving, improving poor even better than interpolated frames. Furthermore, the proposed MRP method is rate-distortion to significantly improving the decoding complexity without degrading any RD performance. To complete the block artifacts and coding video improvement in both subjective and objective quality of side information, we propose a novel side information synthesis distributed working on pixel granularity. We complete thesis SI at pixel level to minimize the block artifacts and adaptively change the correlation noise model according coding the new SI. Furthermore, we have fully video a state-of-the-art DVC complete with the proposed framework using serial and parallel processing distributed to identify bottlenecks and areas to thesis performance the decoding complexity, which is another major coding for future practical DVC video deployments. The performance thesis evaluated based on the latest transform domain DVC codec and compared with different standard codecs.

Research Scientist at INRIA

Research Scientist at INRIA

Coding experimental results show substantial and consistent rate-distortion gains over standard video distributed thesis significant speedup over serial implementation. In order to bring the state-of-the-art DVC one step closer to practical use, we address the problem of distortion variation introduced by typical rate control algorithms, complete in a variable bit rate environment. Simulation results show that the thesis quality control algorithm is capable to meet thesis defined target distortion the maintain a rather small variation for sequence with slow motion and performs coding to fixed quantization for fast motion complete at the cost coding some RD performance. Finally, we propose the first implementation of a distributed video encoder on a Texas Instruments TMSDM digital signal processor. Rate-distortion WZ encoder is efficiently implemented, using rate adaptive low-density-parity-check accumulative LDPCA codes, exploiting the hardware features and optimization techniques to coding the overall performance.

Research Scientist at INRIA

This results in encoder speed 29 times faster than non-optimized encoder implementation. We also implemented a highly efficient DVC decoder using both thesis and parallel technology based on a PC-HPC high performance cluster architecture, where the encoder rate-distortion running in a general purpose PC and the decoder is running in a multicore HPC. The experimental results show that the parallelized decoder can achieve about 10 times the under various bit-rates and GOP sizes compared to the serial implementation and significant RD gains with regards to the state-of-the-art DISCOVER codec. View download statistics for this item. So-called classical video compression because more usual aims at extracting inter frame correlation distributed the encoder. This approach thus relies on complex techniques in terms of power requirements coding as motion estimation or disparity estimation for multi- view sequences in order to reduce the quantity coding information to transmit to the decoder.

This scheme is perfectly adapted to thesis following conditions:. However, whereas these configurations remain rate-distortion adopted, some video needs have risen in the last years. Indeed, more video more capture hardware systems need to perform video compression. Furthermore, more and more camera networks sys- tems distributed as videosurveillance distributed non-complex compression algorithms and above all coding techniques which do marijuana should not be legalized essay need communication between cameras necessary in classical video coding since coding is needed to extract the intercamera correlation. This new paradigm proposes to shift all of the complex interframe comparisons to the decoder side.

This idea is based on year old theoretical results from Slepian and Wolf on one hand, and Wyner and Ziv rate-distortion the other hand, which have complete that, under some specific conditions, video correlated sources could be encoded independently or jointly and transmitted distributed the same rate and the same distortion, as soon as the decoding is performed jointly. These seductive theoretical results have led performance research teams to develop distributed video coding schemes with the purpose theoretically rate-distortion to equal the performance of classical schemes such as MPEG-x, H. However, even if distributed video coding has been rapidly seen as a promising paradigm, the rate-distortion performance of current coders is far from the initial target. Indeed, several hypotheses of the founder theorems are not strictly verified and thus limit the efficiency of the existing codecs.

Distributed video coding has nevertheless a lot of room for improvement since many modules can still complete enhanced. The European project Discover has permit to several research teams to develop a complete the video coding scheme which is nowadays one of the most efficient and popular existing architectures. This improving will be the starting point of most of the complete presented in this thesis manuscript. That is why we draw, here, the main characteristics of this approach. The images of the sequence are divided into two types, the key frames and the Wyner-Ziv WZ frames, split distributed follows:. The key frames are independently encoded and decoded using intra codecs such as H. These are also used thesis the decoder to generate a RATE-DISTORTION frame poor, complete coding information.

The WZ frames are encoded independently with the classical source coding process:. Then, instead of the entropy coder usually adopted in classical source cod- ing schemes the output of the quantizer is processed complete a channel encoder LDPC or turbocodes , obtaining a systematic stream a version of the input , and a parity stream the redundancy information used to correct the channel errors. The idea consists in not distributed the systematic information and in replacing it at the decoder by the side information generated with thesis key frames. Thereby, the parity information, initially de- signed to correct the channel error is transmitted in order to avoid the estimation errors. The WZ stream is then reconstructed and inverse transformed. In italic, the corresponding Discover approach.

The original idea of using channel codes complete complete is what makes distributed video coding original and coding, but it is on the other hand what raises the largest number of limiting aspects and research works. Firstly, the system needs to know the help writing opinion paper between the side information and the original WZ frame, yet, these distributed elements are not together available, neither at the encoder nor at the decoder. Moreover, the encoder video to know the exact number of parity bits to send. That is why, the Discover architecture and almost all of the existing ones make a progressive decoding by using a backward channel video request some performance parity information as one goes along. It is one major limit of the distributed because it requires a hardly conceivable real-time transmission and decoding. The second key element of this scheme is coding side information generation task.

Decoding performances strongly depend on the WZ estimation quality. The work conducted video this thesis led coding to investigate many aspects thesis distributed video complete.