Video Coding Technique Research Articles

Proxy-Based Multi-Stream Scalable Video Adaptation Over Wireless Networks Using Subjective Quality and Rate Models

Despite growing maturity in broadband mobile networks, wireless video streaming remains a challenging task, especially in highly dynamic environments. Rapidly changing wireless link qualities, highly variable round trip delays, and unpredictable traffic contention patterns often hamper the performance of conventional end-to-end rate adaptation techniques such as TCP-friendly rate control (TFRC). Furthermore, existing approaches tend to treat all flows leaving the network edge equally, without accounting for heterogeneity in the underlying wireless link qualities or the different rate utilities of the video streams. In this paper, we present a proxy-based solution for adapting the scalable video streams at the edge of a wireless network, which can respond quickly to highly dynamic wireless links. Our design adopts the recently standardized scalable video coding (SVC) technique for lightweight rate adaptation at the edge. Leveraging previously developed rate and quality models of scalable video with both temporal and amplitude scalability, we derive the rate-quality model that relates the maximum quality under a given rate by choosing the optimal frame rate and quantization stepsize. The proxy iteratively allocates rates of different video streams to maximize a weighted sum of video qualities associated with different streams, based on the periodically observed link throughputs and the sending buffer status. The temporal and amplitude layers included in each video are determined to optimize the quality while satisfying the rate assignment. Simulation studies show that our scheme consistently outperforms TFRC in terms of agility to track link qualities and overall subjective quality of all streams. In addition, the proposed scheme supports differential services for different streams, and competes fairly with TCP flows.

Pattern-based video coding with dynamic background modeling

The existing video coding standard H.264 could not provide expected rate-distortion (RD) performance for macroblocks (MBs) with both moving objects and static background and the MBs with uncovered background (previously occluded). The pattern-based video coding (PVC) technique partially addresses the first problem by separating and encoding moving area and skipping background area at block level using binary pattern templates. However, the existing PVC schemes could not outperform the H.264 with significant margin at high bit rates due to the least number of MBs classified using the pattern mode. Moreover, both H.264 and the PVC scheme could not provide the expected RD performance for the uncovered background areas due to the unavailability of the reference areas in the existing approaches. In this paper, we propose a new PVC technique which will use the most common frame in a scene (McFIS) as a reference frame to overcome the problems. Apart from the use of McFIS as a reference frame, we also introduce a content-dependent pattern generation strategy for better RD performance. The experimental results confirm the superiority of the proposed schemes in comparison with the existing PVC and the McFIS-based methods by achieving significant image quality gain at a wide range of bit rates.

Radio Resource Allocation for Scalable Video Services Over Wireless Cellular Networks

Good quality video services always require higher bandwidth. Hence, to provide the video services e.g., multicast/broadcast services (MBSs) and unicast services along with the existing voice, internet, and other background traffic services over the wireless cellular networks, it is required to efficiently manage the wireless resources in order to reduce the overall forced call termination probability, to maximize the overall service quality, and to maximize the revenue. Fixed bandwidth allocation for the MBS sessions either reduces the quality of the MBS videos and bandwidth utilization or increases the overall forced call termination probability and of course the handover call dropping probability as well. Scalable video coding (SVC) technique allows the variable bit rate allocation for the video services. In this paper, we propose a bandwidth allocation scheme that efficiently allocates bandwidth among the MBS sessions and the non-MBS traffic calls (e.g., voice, unicast, internet, and other background traffic). The proposed scheme reduces the bandwidth allocation for the MBS sessions during the congested traffic condition only to accommodate more calls in the system. Instead of allocating fixed bandwidths for the MBS sessions and the non-MBS traffic, our scheme allocates variable bandwidths for them. However, the minimum quality of the videos is guaranteed by allocating minimum bandwidth for them. Using the mathematical and numerical analyses, we show that the proposed scheme maximizes the bandwidth utilization and significantly reduces the overall forced call termination probability as well as the handover call dropping probability.

An Effective and Innovative Streaming Model for Videos in Mobile Computing

Video streaming in mobiles is based on the stream of traffic over mobile networks. The capacity of wireless link cannot be provided on demand. The poor service quality of video streaming over mobile networks is based on the gap between the link capacity and the traffic demand, along with time-varying link conditions, such as long buffering time and intermittent disruptions. In this paper we propose to develop a new mobile video framework, labeled as AMES-Cloud, which is divided into two main parts: AMoV (adaptive mobile video streaming) and EsoV (Efficient social video sharing). AMoV and EsoV build up the third party agent to provide efficient video streaming services for every mobile user. The AMoV and WSoV will provide the different types of features like, based on the feedback of link quality the AMoV contracts the private agent adaptively adjust her streaming flow with a scalable video coding technique. The second feature EsoV monitors the social network interactions among mobile users, and their private agents try to prefect video content in advance. In this paper we implement a prototype of the AMES-Cloud framework to show its efficiency. For that we propose to show that the third party agents in the cloud can effectively provide the adaptive streaming and perform video sharing.

움직임 보상 보간 프레임에 대한 시공간적 통계특성에 기초한 블록기반의 신뢰도 평가 방법

Motion-compensated frame interpolation (MCFI) techniques in video signal processing have many application areas. Frame rate up-conversion (FRUC) or distributed video coding (DVC) technique needs an effective MCFI algorithm. For these applications, it is necessary to develop an effective post-processing technique to improve visual qualities or to reduce virtual channel noises, resulting in the reduced channel bit rate. This paper proposes a reliability evaluation method based on spatio-temporal characteristics for motion-compensated interpolated blocks. The proposed algorithm investigates the temporal matching characteristics for current frame and then is designed in such a way that it can measure temporal characteristics as well as the spatial ones. Through computer simulations, it is shown that the proposed method outperforms the conventional temporal matching method.

Video Coding and Routing in Wireless Video Sensor Networks

Video represents a form of data that needs large storage space. In addition, and due to the complexity of video coding (encoding/decoding) techniques, they usually involve computationally intensive operations. This imposes heavy burdens upon sending and receiving entities that are required to have high processing power and abundant storage capacity, as well as the network infrastructure transporting video content that is required to have sufficient transmission bandwidth. Therefore, it is important to tailor video coding techniques to resource-constrained wireless sensors. Moreover, the intensive computations needed by video codecs consume substantial power, which is a scarce resource of wireless sensor nodes as they are usually battery powered. Therefore, it is of paramount importance to design power-aware coding, streaming, and routing schemes for the emerging wireless video sensor networks (WVSNs), that also achieve high levels of QoS and QoE. This paper introduces a brief survey of the recently published research on some important topics about WVSNs including video coding and routing and point to possible venues for future research.

Video coding and transmission standards for 3D television — a survey

AbstractThe emerging 3D television systems require effective techniques for transmission and storage of data representing a 3-D scene. The 3-D scene representations based on multiple video sequences or multiple views plus depth maps are especially important since they can be processed with existing video technologies. The review of the video coding and transmission techniques is presented in this paper.

Online Browsing Service of Scenic Based on 3G Wireless Video Network System

Having designed and achieved a sort of wireless video network system based on 3G TDCDMA, this system is applied to provide users witht function which is online browsing service of real-time natural landscape on the Mt. Everest. By means of erecting the video cameras on the Mt. Everest and 3G network service based on H.264 video coding technique to preview post-coding data via WEB server on the internet. Through the use of 3G network technology and H.264 video coding technology, users are able to get access to the video with higher quality, implementing the function of browsing scenery in scenic.

클라우드 컴퓨팅 환경에서의 네트워크 적응적 N-스크린 게임 시스템

본 논문은 클라우드 컴퓨팅 환경에서 새로운 네트워크 적응적 N-스크린 게임 시스템을 설계 및 구현하였다. 목표하는 시스템은 클라우드 서버에서 연산된 게임 화면을 가정에 설치된 게임서버를 통해 한대 이상의 게임 단말로 전송해야 한다. 하지만, 하나의 게임 영상을 가지고 서로 다른 해상도를 가진 N-스크린을 지원하는 것은 어렵고, 무선 네트워크에서의 게임 사용자 이동은 영상 화질을 저하시킨다. 따라서, 본 논문은 스케일러블 비디오 코딩 기술과 채널 코드 기술인 랩터 코드를 이용하여 네트워크 적응적 게임 영상 추출 및 전송 기술을 개발하였다. 실제 게임 영상을 이용한 시뮬레이션 결과는 제안하는 영상 기술의 효율성을 입증한다.

Perceptual-based distributed video coding

In this paper, we propose a perceptual-based distributed video coding (DVC) technique. Unlike traditional video codecs, DVC applies video prediction process at the decoder side using previously received frames. The predicted video frames (i.e., side information) contain prediction errors. The encoder then transmits error-correcting parity bits to the decoder to reconstruct the video frames from side information. However, channel codes based on i.i.d. noise models are not always efficient in correcting video prediction errors. In addition, some of the prediction errors do not cause perceptible visual distortions. From perceptual coding point of view, there is no need to correct such errors. This paper proposes a scheme for the decoder to perform perceptual quality analysis on the predicted side information. The decoder only requests parity bits to correct visually sensitive errors. More importantly, with the proposed technique, key frames can be encoded at higher rates while still maintaining consistent visual quality across the video sequence. As a result, even the objective PSNR measure of the decoded video sequence will increase too. Experimental results show that the proposed technique improves the R-D performance of a transform domain DVC codec both subjectively and objectively. Comparisons with a well-known DVC codec show that the proposed perceptual-based DVC coding scheme is very promising for distributed video coding framework.

Road Map and Challenges in 4G Wireless System

The user demand for high speed multi-media application has been increasing many folds in the recent years. New smart phones are launching in the market. The wireless communication is looking forward for a new generation technology that will match the application demand and resources. This is where the fourth generation (4G) wireless communication is required. 4G wireless communication is expected to provide better speed, high capacity, low cost IP based services. The main objective of the 4G wireless communication is to supersede the current core technology with a single unified technology. More and more advanced interactive multimedia applications are emerging as 4G networks resulting in a rapid development of video coding and communication techniques. This paper deals with the current scenario and the future prospects of the 4G system in addition with the challenges it is going to witness.

A New Method to Evaluate Gaze Behavior Patterns in Doctor-Patient Interaction

Eye gaze behavior is considered an important aspect of doctor-patient nonverbal interaction process in a clinical encounter. Previous research shows that eye gaze behavior patterns works as part of a doctor’s communication style and affects certain medical outcomes. New interventions (behavioral and technological) are continuously being introduced to the clinical encounters due to health care work system redesign and there is a need to evaluate the impact of these interventions on communication. The aim of this study was to develop a systematic approach to evaluate eye gaze behavior patterns using video coding and lag sequential analysis technique. Thirty-two clinical encounters with two interaction styles were analyzed. Differences and similarities in eye gaze behavior pattern were found in the two styles. Implications for interventions and evaluation in doctor-patient interaction are discussed.

A video coding technique with BTC-PF method for fast decoding

A video coding technique with BTC-PF method for fast decoding We have presented a video coding system that enables fast decoding and there by caters the need of the real time applications like video on demand, video play back, video retrieval. Proposed methodology relies on a fast motion estimation scheme, hierarchical BTC-PF based redundancy removal technique and finally it uses entropy decoding. As the encoding method is free from transformation and quantization steps, the decoding becomes faster. It also maintains the quality within the acceptable limit and improves bpp.

Authentication of Scalable Video Streams With Low Communication Overhead

The large prevalence of multimedia systems in recent years makes the security of multimedia communications an important and critical issue. We study the problem of securing the delivery of scalable video streams so that receivers can ensure the authenticity of the video content. Our focus is on recent scalable video coding (SVC) techniques, such as H.264/SVC, which can provide three scalability types at the same time: temporal, spatial, and visual quality. This three-dimensional scalability offers a great flexibility that enables customizing video streams for a wide range of heterogeneous receivers and network conditions. This flexibility, however, is not supported by current stream authentication schemes in the literature. We propose an efficient and secure authentication scheme that accounts for the full scalability of video streams, and enables verification of all possible substreams that can be extracted from the original stream. In addition, we propose an algorithm for minimizing the amount of authentication information that need to be attached to streams. The proposed authentication scheme supports end-to-end authentication, in which any third-party entity involved in the content delivery process, such as stream adaptation proxies and caches, does not have to understand the authentication mechanism. Our simulation study with real video traces shows that the proposed authentication scheme is robust against packet losses, incurs low computational cost for receivers, has short delay, and adds low communication overhead. Finally, we implement the proposed authentication scheme as an open source library called svcAuth, which can be used as a transparent add-on by any multimedia streaming application.

Video coding Technique using 3-D Dual tree Complex Wavelet Transform with Improved Particle Swarm Optimization

Video coding Technique using 3-D Dual tree Complex Wavelet Transform with Improved Particle Swarm Optimization

Error Concealment for Frame Losses in MDC

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <emphasis emphasistype="italic">Multiple description coding</emphasis> (MDC) is an effective <emphasis emphasistype="italic">error resilience</emphasis> (ER) technique for video coding. In case of frame loss, <emphasis emphasistype="italic">error concealment</emphasis> (EC) techniques can be used in MDC to reconstruct the lost frame, with error, from which subsequent frames can be decoded directly. With such direct decoding, the subsequent decoded frames will gradually recover from the frame loss, though slowly. In this paper we propose a novel algorithm using <emphasis emphasistype="italic">multihypothesis error concealment</emphasis> (MHC) to improve the error recovery rate of any EC in the temporal subsampling MDC. In MHC, the simultaneous temporal-interpolated frame is used as an additional hypothesis to improve the reconstructed video quality after the lost frame. Both subjective and objective results show that MHC can achieve significantly better video quality than direct decoding. </para>

Three Dimensional Scalable Video Adaptation via User-End Perceptual Quality Assessment

For wireless video streaming, the three dimensional scalabilities (spatial, temporal and SNR) provided by the advanced scalable video coding (SVC) technique can be directly utilized to adapt video streams to dynamic wireless network conditions and heterogeneous wireless devices. However, the question is how to optimally trade off among the three dimensional scalabilities so as to maximize the perceived video quality, given the available resource. In this paper, we propose a low-complexity algorithm that executes at resource-limited user end to quantitatively and perceptually assess video quality under different spatial, temporal and SNR combinations. Based on the video quality measures, we further propose an efficient adaptation algorithm, which dynamically adapts scalable video to a suitable three dimension combination. Experimental results demonstrate the effectiveness of our proposed perceptual video adaptation framework.

3-D Shape-Adaptive Directional Wavelet Transform for Object-Based Scalable Video Coding

This paper presents a 3-D shape-adaptive directional wavelet coding technique for object-based scalable video coding. This technique includes 3-D object-based directional threading and extensions of weighted adaptive lifting (WAL) scheme. The 3-D object-based directional threading, which unifies the concept of temporal motion threading and 2-D spatial directional threading, provides the opportunities to align a series of video object planes to form a 3-D video object and exploit the spatio-temporal correlation inside the 3-D video object. The WAL scheme, which is extended from 2-D frame-based image coding to 3-D object-based video coding, is employed to decompose the 3-D video object into a 3-D multispatio-temporal resolution video object pyramid for object-based scalable video coding. Experimental results show that the proposed 3-D shape-adaptive directional wavelet coding technique consistently outperforms MPEG-4 and other wavelet-based schemes for coding arbitrarily shaped video objects.

Statistical, DCT and vector quantisation-based video codec

The authors present a novel hybrid statistical, DCT and vector quantisation-based video-coding technique. In intra mode of operation, an input frame is divided into a number of non-overlapping pixel blocks. A discrete cosine transform then converts the coefficients in each block into the frequency domain. Coefficients with the same frequency index at different blocks are put together generating a number of matrices, where each matrix contains the coefficients of a particular frequency index. The matrix, which contains the DC coefficients, is losslessly coded. Matrices containing high frequency coefficients are coded using a novel statistical encoder. In inter mode of operation, overlapped block motion estimation / compensation is employed to exploit temporal redundancy between successive frames and generates a displaced frame difference (DFD) for each inter-frame. A wavelet transform then decomposes the DFD-frame into its frequency subbands. Coefficients in the detail subbands are vector quantised while coefficients in the baseband are losslessly coded. To evaluate the performance of the codec, the proposed codec and the adaptive subband vector quantisation (ASVQ) video codec, which has been shown to outperform H.263 at all bitrates, were applied to a number of test sequences. Results indicate that the proposed codec outperforms the ASVQ video codec subjectively and objectively at all bitrates.

主観評価値の最大化に基づく動画像の時空間レート制御とその符号化への応用

Since the bandwidth required for real-time video communication cannot always be available on a network, the number of frames per second and the average bit amount for a single frame should be controlled suitably to obtain the highest possible video quality in a restricted bandwidth. To alleviate the problem, the authors have developed a spatio-temporal rate control technique that maximizes an estimation of MOS. From a practical point of view, however, this approach offers little freedom in coding-parameter tuning and in the frame rate control. Although improved techniques have been presented for these difficulties, a detailed encoding algorithm under the spatio-temporal rate control has not been investigated. This paper thus proposes a novel spatio-temporal rate control and video coding techniques based on our MOS estimation and frame rate control techniques, and it shows their validity and effectiveness. Some applications of the proposed technique are also discussed. We have determined that 75% of videos encoded by the proposed technique give almost equal or better subjective quality compared with the conventional fixed-frame-rate approach.