Showing papers on "Video quality published in 2008"

Scope of validity of PSNR in image/video quality assessment

Abstract: Experimental data are presented that clearly demonstrate the scope of application of peak signal-to-noise ratio (PSNR) as a video quality metric. It is shown that as long as the video content and the codec type are not changed, PSNR is a valid quality measure. However, when the content is changed, correlation between subjective quality and PSNR is highly reduced. Hence PSNR cannot be a reliable method for assessing the video quality across different video contents.

The Evolution of Video Quality Measurement: From PSNR to Hybrid Metrics

Abstract: This paper reviews the evolution of video quality measurement techniques and their current state of the art. We start with subjective experiments and then discuss the various types of objective metrics and their uses. We also introduce V-Factor, a "hybrid" metric using both transport- and bitstream information. Finally, we summarize the main standardization activities, such as the work of the video quality experts group (VQEG), and we take a look at emerging trends in quality measurement, including image preference, visual attention, and audiovisual quality.

Photo and Video Quality Evaluation: Focusing on the Subject

Abstract: Traditionally, distinguishing between high quality professional photos and low quality amateurish photos is a human task. To automatically assess the quality of a photo that is consistent with humans perception is a challenging topic in computer vision. Various differences exist between photos taken by professionals and amateurs because of the use of photography techniques. Previous methods mainly use features extracted from the entire image. In this paper, based on professional photography techniques, we first extract the subject region from a photo, and then formulate a number of high-level semantic features based on this subject and background division. We test our features on a large and diverse photo database, and compare our method with the state of the art. Our method performs significantly better with a classification rate of 93% versus 72% by the best existing method. In addition, we conduct the first study on high-level video quality assessment. Our system achieves a precision of over 95% in a reasonable recall rate for both photo and video assessments. We also show excellent application results in web image search re-ranking.

An Evaluation Framework for More Realistic Simulations of MPEG Video Transmission

Abstract: We present a novel and complete tool-set for evaluating the delivery quality of MPEG video transmissions in simulations of a network environment. This tool-set is based on the EvalVid framework. We extend the connecting interfaces of EvalVid to replace its simple error simulation model by a more general network simulator like NS2. With this combination, researchers and practitioners in general can analyze through simulation the performance of real video streams, i.e. taking into account the video semantics, under a large range of network scenarios. To demonstrate the usefulness of our new tool-set, we point out that it enables the investigation of the relationship between two popular objective metrics for Quality of Service (QoS) assessment of video quality delivery: the PSNR (Peak Signal to Noise Ratio) and the fraction of decodable frames. The results show that the fraction of decodable frames reflects well the behavior of the PSNR metric, while being less time-consuming. Therefore, the fraction of decodable frames can be an alternative metric to objectively assess through simulations the delivery quality of transmission in a network of publicly available video trace files.

Traffic and Quality Characterization of Single-Layer Video Streams Encoded with the H.264/MPEG-4 Advanced Video Coding Standard and Scalable Video Coding Extension

Abstract: The recently developed H.264/AVC video codec with scalable video coding (SVC) extension, compresses non-scalable (single-layer) and scalable video significantly more efficiently than MPEG-4 Part 2. Since the traffic characteristics of encoded video have a significant impact on its network transport, we examine the bit rate-distortion and bit rate variability-distortion performance of single-layer video traffic of the H.264/AVC codec and SVC extension using long CIF resolution videos. We also compare the traffic characteristics of the hierarchical B frames (SVC) versus classical B frames. In addition, we examine the impact of frame size smoothing on the video traffic to mitigate the effect of bit rate variabilities. We find that compared to MPEG-4 Part 2, the H.264/AVC codec and SVC extension achieve lower average bit rates at the expense of significantly increased traffic variabilities that remain at a high level even with smoothing. Through simulations we investigate the implications of this increase in rate variability on (i) frame losses when transmitting a single video, and (ii) on a bufferless statistical multiplexing scenario with restricted link capacity and information loss. We find increased frame losses, and rate-distortion/rate-variability/encoding complexity tradeoffs. We conclude that solely assessing bit rate-distortion improvements of video encoder technologies is not sufficient to predict the performance in specific networked application scenarios.

Queuing-Based Dynamic Channel Selection for Heterogeneous Multimedia Applications Over Cognitive Radio Networks

Abstract: In this paper, we propose a dynamic channel-selection solution for autonomous wireless users transmitting delay-sensitive multimedia applications over cognitive radio networks. Unlike prior works that seldom consider the requirement of the application layer, our solution explicitly considers various rate requirements and delay deadlines of heterogeneous multimedia users. Note that the users usually possess private utility functions, application requirements, and distinct channel conditions in different frequency channels. To efficiently manage available spectrum resources in a decentralized manner, information exchange among users is necessary. Hence, we propose a novel priority virtual queue interface that determines the required information exchanges and evaluates the expected delays experienced by various priority traffics. Such expected delays are important for multimedia users due to their delay-sensitivity nature. Based on the exchanged information, the interface evaluates the expected delays using priority queuing analysis that considers the wireless environment, traffic characteristics, and the competing users' behaviors in the same frequency channel. We propose a dynamic strategy learning (DSL) algorithm deployed at each user that exploits the expected delay and dynamically adapts the channel selection strategies to maximize the user's utility function. We simulate multiple video users sharing the cognitive radio network and show that our proposed solution significantly reduces the packet loss rate and outperforms the conventional single-channel dynamic resource allocation by almost 2 dB in terms of video quality.

Performance bounds for peer-assisted live streaming

Abstract: Peer-assisted streaming is a promising way for service providers to offer high-quality IPTV to consumers at reasonable cost. In peer-assisted streaming, the peers exchange video chunks with one another, and receive additional data from the central server as needed. In this paper, we analyze how to provision resources for the streaming system, in terms of the server capacity, the video quality, and the depth of the distribution trees that deliver the content. We derive the performance bounds for minimum server load, maximum streaming rate, and minimum tree depth under different peer selection constraints. Furthermore, we show that our performance bounds are actually tight, by presenting algorithms for constructing trees that achieve our bounds.

Quality analysis for 3D video using 2D video quality models

Abstract: The 3D (3-dimensional) video technologies are emerging to provide more immersive media content compared to conventional 2D (2-dimensional) video applications. More often 3D video quality is measured using rigorous and time-consuming subjective evaluation test campaigns. This is due to the fact that 3D video quality can be described as a combination of several perceptual attributes such as overall image quality, perceived depth, presence, naturalness and eye strain, etc. Hence this paper investigates the relationship between subjective quality measures and several objective quality measures like PSNR, SSIM, and VQM for 3D video content. The 3D video content captured using both stereo camera pair (two cameras for left and right views) and colour-and-depth special range cameras are considered in this study. The results show that, VQM quality measures of individual left and right views (rendered left and right views for colour-and-depth sequences) can be effectively used in predicting the overall image quality and statistical measures like PSNR and SSIM of left and right views illustrate good correlations with depth perception of 3D video.

A 60 GHz wireless network for enabling uncompressed video communication

Abstract: Uncompressed high-definition video streaming over wireless personal area networks is a challenging problem because of the high data rate requirement and channel variations. With the advances in RF technology and the huge bandwidth available worldwide in the 57-66 GHz millimeter-wave unlicensed spectrum, mmWave WPANs that can support multigigabit transmission are being developed. However, compared to low-frequency signals (2.4 or 5 GHz), mmWave signals are more fragile; indeed, the propagation losses are significantly higher. In this article we present an mmWave system for supporting uncompressed HD video up to 3 Gb/s. The system includes various efficient error protection and concealment schemes that exploit unequal error resilience properties of uncompressed video. Some of them have been adopted in the emerging 60 GHz WPAN standards such as WirelessHD, ECMA TC48, and IEEE 802.15.3c. Simulations using real uncompressed HD images indicate that the proposed mmWave system can maintain, under poor channel conditions, good average peak-signal-to-noise-ratio and low video quality metric scores.

Real-Time Video Multicast in WiMAX Networks

Abstract: IEEE 802.16e WiMAX is a promising new technology for broadband access networks. Amongst the class of applications that can be supported is real time video services (such as IPTV, broadcast of live events etc.). These applications are bandwidth hungry and have stringent delay constraints. Thus, scalable support for such applications is a challenging problem. To address this challenge, we consider a combination of approaches using multicast, layer encoded video and adaptive modulation of transmissions. Using these, we develop algorithms to ensure efficient, fair and timely delivery of video in WiMAX networks. The corresponding resource allocation problem is challenging because scheduling decisions (within a WiMAX base station) are performed in real-time across two dimensions, time and frequency. Moreover, combining layered video with appropriate modulation calls for novel MAC algorithms. We model the multicast resource allocation problem in WiMAX and demonstrate this problem to be NP-hard. We present a fast greedy algorithm that is (i) provably within a constant approximation of the optimal solution (based on a metric that reflects video quality as perceived by the user), and (ii) performs within 87-95% of the optimal as demonstrated by realistic simulations. We also demonstrate that our algorithm offers a 25% improvement over a naive algorithm. Moreover, in terms of the average rate received by each user, our algorithm out-performs the naive algorithm by more than 50%.

Parametric Packet-Layer Model for Monitoring Video Quality of IPTV Services

Abstract: IPTV services will become key services in the next- generation network (NGN). To provide a high-quality service for users, designing and managing the quality of experience (QoE) appropriately is extremely important. To do this, developing an objective quality-assessment method that estimates subjective quality based on physical characteristics of the IPTV system is desirable. We propose a parametric packet-layer model for monitoring video quality of IPTV services. Our proposed model is useful as a network monitoring tool for assessing several video parameters that affect the quality of IPTV services. For constructing the parametric packet-layer model, we derived a relationship between video quality and quality parameters from a subjective quality assessment. The results indicated that cross- correlation was larger than 0.9, and the evaluation error was smaller than the statistical uncertainty of the value of subjective quality. Therefore, our proposed model could be applied to effective design, implementation, and management of IPTV services.

Temporal Aspect of Perceived Quality in Mobile Video Broadcasting

Abstract: In this paper we describe a subjective quality assessment experiment conducted to measure the impact of temporal artifacts on video quality and characterize the influence of content motion on perceived quality. We examined the human response to jerkiness and jitter by considering different levels of strength, duration and distribution of the temporal impairments. Using videos with high picture quality, we found that for intermediate and high frame rate values video quality was similar independently from the duration of the frame rate decimation. On the other hand, for very low frame rates, overall video quality decreased as the duration of the impairment increased. The results also show that a reduction of the temporal resolution over the entire video does not necessarily lead to a significant loss of quality. Finally, the results of this study do not confirm the traditional thinking of lower-motion content receiving a higher quality than high-motion content for a given frame rate decimation factor. Using several motion descriptors, we observed that for a given sub-optimum frame rate, perceived quality does not necessarily increase with decreasing motion magnitude. More particularly, we found that perceived quality of head-and-shoulders content is severely affected by frame rate decimation although it is characterized by very low motion. Our results suggest that motion magnitude is not the only factor affecting perception of temporal artifacts.

Cross-Dimensional Perceptual Quality Assessment for Low Bit-Rate Videos

Abstract: Most studies in the literature for video quality assessment have been focused on the evaluation of quantized video sequences at fixed and high spatial and temporal resolutions. Only limited work has been reported for assessing video quality under different spatial and temporal resolutions. In this paper, we consider a wider scope of video quality assessment in the sense of considering multiple dimensions. In particular, we address the problem of evaluating perceptual visual quality of low bit-rate videos under different settings and requirements. Extensive subjective view tests for assessing the perceptual quality of low bit-rate videos have been conducted, which cover 150 test scenarios and include five distinctive dimensions: encoder type, video content, bit rate, frame size, and frame rate. Based on the obtained subjective testing results, we perform thorough statistical analysis to study the influence of different dimensions on the perceptual quality and some interesting observations are pointed out. We believe such a study brings new knowledge into the topic of cross-dimensional video quality assessment and it has immediate applications in perceptual video adaptation for scalable video over mobile networks.

Joint Source Adaptation and Resource Allocation for Multi-User Wireless Video Streaming

Abstract: Multi-user video streaming over wireless channels is a challenging problem, where the demand for better video quality and small transmission delays needs to be reconciled with the limited and often time-varying communication resources. This paper presents a framework for joint network optimization, source adaptation, and deadline-driven scheduling for multi-user video streaming over wireless networks. We develop a joint adaptation, resource allocation and scheduling (JARS) algorithm, which allocates the communication resource based on the video users' quality of service, adapts video sources based on smart summarization, and schedules the transmissions to meet the frame delivery deadlines. The proposed algorithm leads to near full utilization of the network resources and satisfies the delivery deadlines for all video frames. Substantial performance improvements are achieved compared with heuristic schemes that do not take the interactions between multiple users into consideration.

Prediction of stereoscopic video quality using objective quality models of 2-D video

Abstract: The timely deployment of three-dimensional (3-D) video applications requires accurate objective quality measures, so that time consuming subjective tests can be avoided. Investigated is the correlation between subjective and objective evaluations of colour plus depth map 3-D video. Subjective tests are performed to determine the overall image quality and depth perception of a range of asymmetrically coded video sequences. The subjective results are used to determine more accurate objective quality assessment metrics for colour plus depth map based stereoscopic video.

Real-time monitoring of video quality in IP networks

Abstract: This paper investigates the problem of assessing the quality of video transmitted over IP networks. Our goal is to develop a methodology that is both reasonably accurate and simple enough to support the large-scale deployments that the increasing use of video over IP are likely to demand. For that purpose, we focus on developing an approach that is capable of mapping network statistics, e.g., packet losses, available from simple measurements, to the quality of video sequences reconstructed by receivers. A first step in that direction is a loss-distortion model that accounts for the impact of network losses on video quality, as a function of application-specific parameters such as video codec, loss recovery technique, coded bit rate, packetization, video characteristics, etc. The model, although accurate, is poorly suited to large-scale, on-line monitoring, because of its dependency on parameters that are difficult to estimate in real-time. As a result, we introduce a ldquorelative qualityrdquo metric (rPSNR) that bypasses this problem by measuring video quality against a quality benchmark that the network is expected to provide. The approach offers a lightweight video quality monitoring solution that is suitable for large-scale deployments. We assess its feasibility and accuracy through extensive simulations and experiments.

Video Quality Estimation for Mobile H.264/AVC Video Streaming

Abstract: The scope of this paper is the estimation of subjective video quality for low-resolution video sequences as they are typical for mobile video streaming. Although the video quality experienced by users depends on spatial (edges, colors, ...) and more considerably on temporal (movement speed, direction, ...) features of the video sequence, most of the well-known methods are based on spatial features. This paper presents a new reference-free approach for quality estimation based on motion characteristics. The character of motion is determined by the amount and direction of the motion between two scene changes. In this paper, two methods are presented. The first method, presents the design of a quality metric based on content adaptive parameters, allowing for content dependent video quality estimation. The second method estimates video quality in two steps. Firstly, the content classification with character sensitive parameters is carried out. Finally, based on the content class, frame rate and bitrate, the video quality is estimated. The performance of the proposed methods is evaluated and compared to the ANSI T1.801.03 metric. The results show that the motion-based approach provides powerful means of estimating the video quality experienced by users for low resolution video streaming services.

Modeling the impact of frame rate on perceptual quality of video

Abstract: This study aims to understand how perceived quality of a video varies as the frame rate changes. We find that an inverted falling exponential function can accurately reflect the trend observed from subjective testing. We further explore the relationship between the falling rate and the video content features, such as frame difference, motion, and contrast.

Substream Trading: Towards an open P2P live streaming system

Abstract: We consider the design of an open P2P live-video streaming system. When designing a live video system that is both open and P2P, the system must include mechanisms that incentivize peers to contribute upload capacity. We advocate an incentive principle for live P2P streaming: a peerpsilas video quality is commensurate with its upload rate. We propose substream trading, a new P2P streaming design which not only enables differentiated video quality commensurate with a peerpsilas upload contribution but can also accommodate different video coding schemes, including single-layer coding, layered coding, and multiple description coding. Extensive trace-driven simulations show that substream trading has high efficiency, provides differentiated service, low start-up latency, synergies among peers with different Internet access rates, and protection against free-riders.

Content-Aware Playout and Packet Scheduling for Video Streaming Over Wireless Links

Abstract: Media streaming over wireless links is a challenging problem due to both the unreliable, time-varying nature of the wireless channel and the stringent delivery requirements of media traffic. In this paper, we use joint control of packet scheduling at the transmitter and content-aware playout at the receiver, so as to maximize the quality of media streaming over a wireless link. Our contributions are twofold. First, we formulate and study the problem of joint scheduling and playout control in the framework of Markov decision processes. Second, we propose a novel content-aware adaptive playout control, that takes into account the content of a video sequence, and in particular the motion characteristics of different scenes. We find that the joint scheduling and playout control can significantly improve the quality of the received video, at the expense of only a small amount of playout slowdown. Furthermore, the content-aware adaptive playout places the slowdown preferentially in the low-motion scenes, where its perceived effect is lower.

T-V-model: Parameter-based prediction of IPTV quality

Abstract: The paper presents a parameter-based model for predicting the perceived quality of transmitted video for IPTV applications. The core model we derived can be applied both to service monitoring and network or service planning. In its current form, the model covers H.264 and MPEG-2 coded video (standard and high definition) transmitted over IP-links. The model includes factors like the coding bit-rate, the packet loss percentage and the type of packet loss handling used by the codec. The paper provides an overview of the model, of its integration into a multimedia model predicting audio-visual quality, and of its application to service monitoring. A performance analysis is presented showing a high correlation with the results of different subjective video quality perception tests. An outlook highlights future model extensions.

Peer-to-Peer Live Multicast: A Video Perspective

Abstract: Peer-to-peer multicast is promising for large-scale streaming video distribution over the Internet. Viewers contribute their resources to a peer-to-peer overlay network to act as relays for the media streams, and no dedicated infrastructure is required. As packets are transmitted over long, unreliable multipeer transmission paths, it is particularly challenging to achieve consistently high video quality and low end-to-end delay. In this paper, we focus on error-resilient transport for peer-to-peer video streaming. The algorithms we describe are representative of three broad categories of robust video streaming schemes: forward error correction, multiple descriptions, and prioritized automatic repeat request. We analyze how these techniques can be employed for live peer-to-peer multicast and discuss their relative merits. Our results show that significant gains can be obtained when systems are designed to adapt to the encoding structure of the video streams they are transmitting. They also reveal the importance of avoiding congestion at every peer participating in the multicast to obtain a low-latency system. Finally, we provide insights as to which are the important metrics to compare different peer-to-peer streaming systems.

A Framework of Cross-Layer Superposition Coded Multicast for Robust IPTV Services over WiMAX

Abstract: A cross-layer design (CLD) framework for robust and efficient video multicasting over IEEE 802.16 (or WiMAX) is introduced. In the framework, multiple description coding on scalable video bitstreams at the source for achieving multi-resolution robustness is jointly designed with superposition coding (i.e., multi-resolution modulation) on multicast signals at the channel to overcome the channel diversity problem in wireless multicast. The resulting cross-layer coded multicast signals enable us to recover some lost bitstreams in high quality layers, which is not possible if multi-resolution modulation is used alone for multicasting as in previous works. Simulation results show that indeed our joint design outperforms the scheme using only superposition coded multicast by achieving better video quality for users under multi-user channel diversity.

A Link Adaptation Scheme for Efficient Transmission of H.264 Scalable Video Over Multirate WLANs

Abstract: In this paper, we propose a cross-layer optimization scheme for delivery of scalable video over multirate wireless networks, in particular the popular 802.11 based wireless local area network (WLAN). The 802.11 based networks use a link adaptation mechanism in the physical layer (PHY) to maintain the reliability of transmission under varying channel conditions. When channel condition worsens, the reliability is maintained by employing more robust modulation and coding schemes, at the cost of reduced PHY bit rate. The reduced bit rate will result in lower available throughput for applications. For scalable video streaming applications, the conventional solution to this problem is to reduce the video bit rate by dropping the higher enhancement layers of the scalable video. We show in this article that the video quality can be improved, if the link adaptation scheme uses more intelligent reliability criteria and adjusts the PHY parameters used for delivering each video layer, according to the relative importance of that layer. Our scheme achieves better video quality without increasing the traffic load of the WLAN. For this purpose we present temporal fairness constraints and formulate an optimization problem for assigning different PHY modes to different layers of scalable video; the solution to this problem provides a set of PHY configuration parameters that achieve the highest possible video quality while meeting the admission control constraints in the network. Performance evaluations demonstrate that our method outperforms the existing mechanisms.

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

Abstract: 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.

Linear Rate Control and Optimum Statistical Multiplexing for H.264 Video Broadcast

Abstract: The H.264 video coding standard achieves significantly improved video compression efficiency and finds important applications in digital video broadcast. To enable H.264 video encoding for digital TV broadcast and maximize its broadcast efficiency, there are two important issues that need to be adequately addressed. First, we need to understand the complex coding mechanism of an H.264 video encoder and develop a model to analyze and control its rate-distortion (R-D) behavior in an accurate and robust manner. Second, the R-D behaviors of individual channels in the broadcast system should be jointly controlled and optimized under bandwidth and buffer constraints so as to maximize the overall broadcast quality. In this paper, we develop a linear rate model and a linear rate control scheme for H.264 video coding. We develop an optimum statistical multiplexing system to allocate bits across video programs (each being encoded by an H.264 encoder) and video frames so that the overall video broadcast quality is maximized. We study the bandwidth and buffer constraints in video broadcast and formulate the optimum statistical multiplexing into a constrained mathematical optimization problem. Realizing that it is impossible to find a close-form solution for global optima, we propose a simple yet efficient algorithm to find a near-optimum solution for joint rate allocation under buffer constraints. Our extensive simulation results demonstrate that the proposed statistical multiplexing system achieves about 40-50% saving in bandwidth, provides a smooth video quality change across programs and frames, and maintains robust decoder buffer control.

Traffic characteristics of H.264/AVC variable bit rate video

Abstract: The recently developed H.264/AVC encoder compresses video significantly more efficiently than previous encoders and is expected to be used for compressing the majority of video transported over communication networks. The traffic characteristics of encoded video have a significant impact on the network transport of compressed video, making it very important to study the characteristics of H.264/AVC video traffic. In this article, we examine the bit-rate distortion performance, bit-rate variability, and long-range dependence of the H.264/AVC encoder for long videos up to high-definition resolution. We also explore the impact of smoothing on the H.264/AVC video traffic. We find that compared to the MPEG-2 and MPEG-4 Part 2 encoders, H.264/AVC achieves lower average bit rates for a given video quality at the expense of significantly increased traffic variability that remains at high levels even with smoothing.

Quality assessment of 3D video in rate allocation experiments

Abstract: In this contribution, we address the problem of measuring and optimizing the visual quality of encoded 3D video. The 3D video is represented in the format of monoscopic color video augmented by per-pixel depth map and then encoded with H.264 encoder. To optimize the encoding performance we test different bit budgets for the color video and the depth and measure the quality by virtual view quality metrics. Small scale subjective tests supplement the objective measurements. The obtained results show that, for similar overall quality numbers, observers favorably trade off lower depth quality for higher color quality and that depth distortions are perceived but considered less significant than the color distortions.

Reduced-Reference Video Quality Assessment Using Discriminative Local Harmonic Strength With Motion Consideration

Abstract: This paper presents a reduced-reference objective picture quality measurement tool of compressed video. We have used a discriminative analysis of harmonic strength computed from edge-detected pictures to create harmonics gain and loss information that could be associated with the picture. The harmonics gain/loss are derived through the harmonic analysis of the compressed and source pictures to be incorporated in the reduced-reference video quality meter. This information corresponds with the two most prominent compression distortions, namely blockiness and blurriness. We have also studied the impact of motion in a video sequence on these compression distortions and the way they should be weighted and combined to give the best objective quality metric model. The model has been calibrated using several video sequences with dominant blockiness and blurriness. Validation of the model is performed by applying the model to the 50 Hz video sequences of VQEG Test Phase-I. Our results show that the proposed model achieves good correlations with the subjective evaluations of the VQEG datasets and its performance is comparable to those of the full-reference models in the literature.

Personalized and mobile digital TV applications

Abstract: The introduction of mobile and broadband networks in complement to the existing satellite, cable, and terrestrial platforms, opens new opportunities for interactive TV (ITV) applications In addition, the widespread adoption of multimedia computing has enabled the processing of TV content on personal devices such as mobile phones and PCs The above developments raise novel issues and require the adoption of new multimedia standards and application frameworks In particular, the explosion in the amount of available TV channels over digital television platforms (broadcast or internet protocol) makes searching and locating interesting content a cumbersome task In this context, personalization research is concerned with the adaptation of content (eg movies, news, advertisements) Personalization is achieved with the employment of algorithms and data collection schemes that predict and recommend to television viewers content that match their interests In addition, the distribution of TV content to mobile devices over broadband wireless raises the issue of video quality Video quality depends on many aspects of the video encoding systems, such as bit rate and algorithms that model human perception of video on small screens In this article, we examine contemporary research in personalized and mobile digital TV applications Moreover, we present a critical survey of the most prominent research and provide directions for further research in personalized and mobile digital TV (DTV) applications