Rate-distortion optimized frame dropping and scheduling for multi-user conversational and streaming video

We propose a Rate-Distortion (RD) optimized strategy for frame-dropping and scheduling of multi-user conversa- tional and streaming videos. We consider a scenario where conversational and streaming videos share the forwarding resources at a network node. Two buffers are setup on the node to temporarily store the packets for these two types of video applications. For streaming video, a big buffer is used as the associated delay constraint of the application is moderate and a very small buffer is used for conversational video to ensure that the forwarding delay of every packet is limited. A scheduler is located behind these two buffers that dynamically assigns transmission slots on the outgoing link to the two buffers. Rate-distortion side information is used to perform RD-optimized frame dropping in case of node overload. Sharing the data rate on the outgoing link between the con- versational and the streaming videos is done either based on the fullness of the two associated buffers or on the mean incoming rates of the respective videos. Simulation results showed that our proposed RD-optimized frame dropping and scheduling ap- proach provides significant improvements in performance over the popular priority-based random dropping (PRD) technique.

Rate-distortion optimized bitstream switching for peer-to-peer live streaming

Peer-to-peer (P2P) technology provides a cost-effective and scalable way to distribute video data. However, high heterogeneity of the P2P network, which rises not only from heterogeneous link capacity between peers but also from dynamic variation of available bandwidth, brings forward great challenge to video streaming. To attack this problem, an adaptive scheme based on rate-distortion optimization (RDO) is proposed in this paper. While low complexity RDO based frame dropping is exploited to shape bitrate into available bandwidth in peers, the streamed bitstream is dynamically switched among multiple available versions in an RDO way by the streaming server. Simulation results show that the proposed scheme based on RDO achieves great gain in overall perceived quality over simple heuristic schemes.

A rate-distortion optimized rate shaping scheme for H.264 data partitioned video bitstream

To enable quality sealability and further improve the reconstructed video quallty m rate shaping, a rate-distortion optimized packet dropping scheme for H. 264 data partitioned video bitstream is proposed in this paper. Some side information is generated for each video bitstream in advance, while streaming such side information is exploited by a greedy algorithm to optimally drop partitions in a rate-distortion optimized way. Quality sealability is supported by adopting data partition instead of whole frame as the dropping unit. Simulation resuhs show that the proposed scheme achieves a great gain in the reconstructed video quality over two typical frame dropping schemes, with the help of the fine granularity in dropping unit as well as rate-distortion optimization.

A Novel Algorithm of Solving the Optimal Slope on Rate-distortion Curve for the Given Rate Budget

Rate-distortion optimization greatly improves the performance of compression coding system so that it pervades all of the source coding from an informationtheoretic standpoint and for the design of practical coding systems. For the case of rate-distortion optimization, Lagrange multiplier method provides the efficient and nearly optimal solution. In this paper, a fast and efficient algorithm is proposed to solve the optimal slope λ＊ of the rate-distortion curve at the given bit budget. Based on Lagrange multiplier method, the presented algorithm find λ＊ using the golden-ratio search. Compared with the Bisection method that only adapts to the system with the dense operational points on the rate-distortion curve, the proposed algorithm can be adapted to the system whether the operational points are populated densely or not. Thus it can be applied to both the wavelet coding system and the video coding standards such as H. 264, where Bisection method can not work well. In particular, the algorithm has been verified on the platform of the quadtree classified and trellis coded quantized （QTCQ） wavelet image compression system and the newest video coding standard H. 264. The experimental results are provided to demonstrate the efficiency of the algorithm. The proposed algorithm can improve the performance. A gain abour 0.6 - 0.7 dB can be achieved with the same rate in H. 264. In addition, it converges as fast as Bisection method, with almost the same ctinplexity.

PRE-Processing for Video Coduing with Rate-Distortion Optimization Decision

This paper proposes an adaptive video pre-processing algorithm for video coding. This algorithm works on the original image before intraor inter-prediction. It adopts Gaussian filter to remove noise and insignificant features existing in images of video. Detection and restoration of edges are followed to restore the edges which are excessively filtered out in filtered images. Rate-Distortion Optimization （RDO） is employed to decide adaptively whether a processed block or a unprocessed block is coded into bit-streams doe more efficient coding. Our experiment results show that the algorithm achieves good coding performances on both subjective and objective aspects. In addition, the proposed pre-processing algorithm is transparent to decoder, and thus can be compliant with any video coding standards without modifying the decoder.

A Rate-distortion Based Quantization Level Adjustment Algorithm in Block-based Video Compression

In this paper, a rate-distortion based quantization level adjustment （RDQLA） algorithm is presented. Based on the rate-distortion criterion, the quantization level adjustment algorithm effectively improves coding efficiency by adaptively optimizing quantization levels of the signals near the boundaries of quantization cells and adjusting quantization levels per block. In addition, it has no overhead and is fully compatible with the existing compression standards. The proposed algorithm can be applied in any block based image and video coding method. In particular, the algorithm has been verified on the platform of H.264. Experimental results show that the proposed algorithm improves objective and subjective performances substantially. It is shown that the proposed algorithm has a gain of several dB comparing with the newest H.264 standard for high bit rates.

A novel intra refresh scheme for wireless video transmission

The burst error of wireless channels and the two-state Markov wireless model are analyzed. Based on this model and the coding modes of the video encoder,the channel distortion of inter-coding and intra-coding due to burst error is deduced. Then we propose a novel intra refresh scheme in rate-distortion (R-D) framework. This scheme optimizes the error resilience and coding efficiency of wireless video transmission system. It can also stop error propagation and reduce channel distortion effectively. Simulations under different channel conditions verify the improvements of the proposed scheme with respect to error resilience for wireless video communication.

Source extension based on ε-entropy

It is known by entropy theory that image is a source correlated with a certain characteristic of probability. The entropy rate of the source and ε- entropy (rate-distortion function theory) are the information content to identify the characteristics of video images, and hence are essentially related with video image compression. They are fundamental theories of great significance to image compression, though impossible to be directly turned into a compression method. Based on the entropy theory and the image compression theory, by the application of the rate-distortion feature mathematical model and Lagrange multipliers to some theoretical problems in the H.264 standard, this paper presents a new the algorithm model of coding rate-distortion. This model is introduced into complete test on the capability of the test model of JM61e (JUT Test Model). The result shows that the speed of coding increases without significant reduction of the rate-distortion performance of the coder.

On Wyner-Ziv Problem for general sources with average distortion criterion

The Wyner-Ziv Problem for general sources with average distortion under fixed-length coding is investigated in this paper. To solve the problem,an enhanced covering lemma for a Markov chain is first established. Then based on the lemma,a general formula for the rate-distortion function of the problem is derived,where the distortion is only assumed uniformly bounded and may be nonadditive. Finally,it is further pointed out that such methods can be used to establish more general results on multiterminal source coding problems.

Frame-layer bit allocation for multi-view video coding based on frame complexity estimation

Current multi-view video coding （MVC） reference model in joint video team （JVT） does not provide efficient rate control schemes. This paper presents a rate control algorithm for MVC by improving the quadratic rate-distortion （R-D） model. We reasonably allocate bit-rate among views based on the correlation analysisl The proposed algorithm consists of three levels to control the rate bits more accurately, of which the frame layer allocates bits according to the frame complexity and the temporal activity. Extensive experiments show that the proposed algorithm can control the bit rate efficiently.

Research on the Bit Computation Model for Time Variable Channel Bandwidth

For the encoding bit-rate problem in H.264 wireless video communication, this paper analyzes the bit-rate computation model and the Mean Square Error distortion model, establishes the relation between the quantization parameter of the encoding bit-rate and the intra frame refresh rate of the macro block, and put forward a new ideal about the coding rate on the basis of general binomial computation model theory. Furthermore, this method not only can adaptively adjust the bit allocation and quantization pa rameter and prevents buffer from overflowing downward or upward under given network bandwidth, but also can apply the rate-distortion to optimize the solution method, control the encoding bits accurately and optimizes the allocation between the intra and inter frame encoding macro block.

Variable Bit Rate Fuzzy Control for Low Delay Video Coding

Rate control plays a critical role in achieving perceivable video quality under a variable bit rate,limited buffer sizes and low delay applications.Since a rate control system exhibits non-linear and unpredictable characteristics,it is difficult to establish a very accurate rate-distortion(R-D)model and acquire effective rate control performance.Considering the excellent control ability and low computing complexity of the fuzzy logic in non-linear systems,this paper proposes a bitrate control algorithm based on a fuzzy controller,named the Fuzzy Rate Control Algorithm(FRCA),for All-Intra(AI)and low-delay(LD)video source coding.Contributions of the proposed FRCA mainly consist of four aspects.First,fuzzy logic is adopted to minimize the deviation between the actual and the target buffer size in the hypothetical reference decoder(HRD).Second,a fast lookup table is employed in fuzzy rate control,which reduces computing cost of the control process.Third,an input domain determination scheme is proposed to improve the precision of the fuzzy controller.Fourth,a novel scene change detection is introduced and integrated in the FRCA to adaptively adjust the Group-of-Pictures(GOP)length when the source content fluctuates.The FRCA can be transplanted and implemented in various industry coders.Extensive experiments show that the FRCA has accurate variable bit-rate control ability and maintains a steady buffer size during the encoding processes.Compared with the default configuration encoding under AI and LD,the proposed FRCA can achieve the target bit rates more accurately in various classical encoders.

High-Efficiency Video Coder in Pruned Environment Using Adaptive Quantization Parameter Selection

The high-efficiency video coder(HEVC)is one of the most advanced techniques used in growing real-time multimedia applications today.However,they require large bandwidth for transmission through bandwidth,and bandwidth varies with different video sequences/formats.This paper proposes an adaptive information-based variable quantization matrix(AIVQM)developed for different video formats having variable energy levels.The quantization method is adapted based on video sequence using statistical analysis,improving bit budget,quality and complexity reduction.Further,to have precise control over bit rate and quality,a multi-constraint prune algorithm is proposed in the second stage of the AI-VQM technique for pre-calculating K numbers of paths.The same should be handy to selfadapt and choose one of the K-path automatically in dynamically changing bandwidth availability as per requirement after extensive testing of the proposed algorithm in the multi-constraint environment for multiple paths and evaluating the performance based on peak signal to noise ratio(PSNR),bit-budget and time complexity for different videos a noticeable improvement in rate-distortion(RD)performance is achieved.Using the proposed AIVQM technique,more feasible and efficient video sequences are achieved with less loss in PSNR than the variable quantization method(VQM)algorithm with approximately a rise of 10%–20%based on different video sequences/formats.

The partial side information problem with additional reconstructions

We consider a quadratic Gaussian distributed lossy source coding setup with an additional constraint of identical reconstructions between the encoder and the decoder.The setup consists of two correlated Gaussian sources,wherein one of them has to be reconstructed to be within some distortion constraint and match with a corresponding reconstruction at the encoder,while the other source acts as coded side information.We study the tradeoff between the rates of two encoders for a given distortion constraint on the reconstruction.An explicit characterization of this trade-off is the main result of the paper.We also give close inner and outer bounds for the discrete memoryless version of the problem.

JPEG2000 COMPRESSION CODING USING HUMAN VISUAL SYSTEM MODEL

In order to apply the Human Visual System (HVS) model to JPEG2000 standard,several implementation alternatives are discussed and a new scheme of visual optimization isintroduced with modifying the slope of rate-distortion. The novelty is that the method of visual weighting is not lifting the coefficients in wavelet domain, but is complemented by code stream organization. It remains all the features of Embedded Block Coding with Optimized Truncation (EBCOT) such as resolution progressive, good robust for error bit spread and compatibility of lossless compression. Well performed than other methods, it keeps the shortest standard codestream and decompression time and owns the ability of VIsual Progressive (VIP) coding.

Novel Rate-Control Algorithm Based on TM5 Framework

Rate control is a key technology in the fields of video coding and transmission, and it has attracted a great attention and has been studied extensively. The TM5 framework of MPEG-2 is a classical rate control algo-rithm and has being widely used. However, it has some underlying drawbacks during practical applications such as the poor rate control precision and high computational complexity. Hence, in this paper, a novel rate-control algorithm based on the TM5 framework is proposed. The drawback of the target bit allocation method of the original TM5 algorithm is firstly analyzed and improved. Then, a new rate-distortion model is incorporated into the rate control algorithm to implement rate prediction to enhance the rate-control precision. Meanwhile, the macro-block (MB) level rate control is adapted to be frame level to reduce the computational complexity. Experiments are conducted and some results are given. Compared with the original TM5 algo-rithm, the improved novel algorithm not only can enhance the rate-control precision but also can reduce the complexity and the fluctuation of decoded image quality.

An end-to-end robust approach for scalable video over the Internet

This paper introduces an end-to-end robust approach for scalable video over the Internet. The traditional method only considers congestion control, error control and is unable to achieve end-to-end high-quality video transmission in the error-prone environment like the Internet since it does not consider the packetization behavior, network conditions and the media characteristics simultaneously. This paper presents an end-to-end approach for scalable video over the Internet, combining network adaptive congestion control and unequal error control. Considering requirements of multimedia transmission, this paper introduces multimedia congestion control to estimate available bandwidth and smooth the media sending rate. Specially in the transport layer we propose unequal interleaving packetization method and unequal error protection scheme, which can alleviate the effect of the packet loss well. Further we develop the rate-distortion theory for the scalable video over the Internet. Thereafter the optimal bit allocation is presented to determine the bits budgets for the source part and error control part. Simulation shows our scheme can achieve good performance for scalable video over the Internet.

STRONG CODING THEOREM AND ASYMPTOTICERROR EXPONENT OF ARBITRARILY VARYING SOURCE WITH A FIDELITY CRITERION

When the error probability is less than 2--"", the minimum compression rate(r-optimal rate) of arbitrarily varying source with a fidelity criterion is determined. Thisgeneralizes the result of Arutyunyan and Mekaushll] for discrete memoryless source witha fidelity criterion, and is called strong coding theorem of arbitrarily varying source witha fidelity criterion. We also determine the asymptotic error exponellt for arbitrarily varying source with a fidelity criterion. This generalizes Marton’s result in [2] for discretememoryless source with a fidelity criterion.

M3FEC:Joint Multiple Description Coding and Forward Error Correction for Interactive Multimedia in Multiple Path Transmission

The best-effort internet has inherent limitations on the end-to-end performance for interactive multimedia communications. This paper presents a multiple description coding （MDC） and forward error correction （FEC） based multiple path transmission schemes for interactive multimedia （M3FEC）, which improves the end users’ experience by maximizing a rate-distortion （R-D） based optimization problem. The proposed model considers both the network diversity and the application’s stringent requirements, and combines the individual merits of the three promising technologies of multiple path overlay routing, MDC and FEC. Extensive numerical analysis and PlanetLab experiments demonstrate that M3FEC successfully combats packet losses, error propagation, and unpredictable network dynamics. This method also significantly increases distortion for interactive multimedia by over 10 dB than traditional IP-layer single path transmission in poor network environments, and outperforms the performance achieved by using MDC or FEC alone.

A Two-Layer Real-Time Rate Control Algorithm Based on Lagrange Optimum Algorithm

Because of the iterative process in the rate control algorithm of the H.264 draft, it is not suitable for real-time transmission. A two-layer real-time rate control algorithm based on the Lagrange optimum algorithm is proposed. This algorithm consists of two layers, namely, the group of pictures （GOP） layer and the frame layer. The simulation results show that the proposed algorithm is competitive in terms of peak signal-to-noise ratio （PSNR）, real bitrates and the Q-value among frames over the original algo- rithm.