Editorial: Technologies for interactive multimedia services

The last few years have witnessed a significant development in the means to produce and make available multimedia content, namely owing to the democratisation of access to digital picture and video cameras in addition to the generalisation of Internet usage. The trend now is to allow ubiquitous access to this ever-increasing amount of multimedia content, enabling a user to find effectively the desired information. This Special Section of IEE Proceedings Vision, Image & Signal Processing addresses some of the enabling technologies for providing interactive multimedia services. All the papers in this Special Section correspond to extended versions of papers presented at the 5th International Workshop on Image Analysis for Multimedia Interactive Services (WIAMIS) held in April 21-23, 2004, at the Instituto Superior Te/spl acute/cnico, Lisboa, Portugal.     

DVB specifications for broadcast-related interactive TV services

Following on from the early success of the Digital Video Broadcasting (DVB) Project, the next step is to enable DVB-compliant receivers to support an attractive range of interactive services. Various types of interactive services are described. The implications for standards are then listed and the specifications summarised. The specifications include a set of network-independent protocols, as well as specifications for the most popular types of networks for the interaction channel. These cover the public switched telephone network (PSTN) and its digital equivalent (ISDN), as well as cable TV networks. The opportunity exists to enhance the consumer experience by adding interactivity to digital broadcasting. DVB is putting in place some of the enablers to make this a reality     

Servers for BT’s interactive TV services

Servers are a major component in an interactive TV service, and once systems of only modest size are considered, the technology requirements are challenging. If BT moves to a roll-out of broadband interactive TV services, then close working with chosen suppliers will be required if costs are to be viable. This paper looks at some server architectures and technologies that might eventually be part of BT’s interactive TV service.     

Throughput-maximizing timeslot scheduling for interactive satellite multiclass services

We develop an efficient method for optimal timeslot scheduling in an interactive satellite multimedia network. We formulate the timeslot assignment problem as a binary integer programming (BIP) problem, where the throughput is maximized, and decompose this BIP problem into two sub-problems. With this decomposition, we promote the computational efficiency in finding the optimal solution of the original BIP problem.     

DAVIC and interactive multimedia services

DAVIC is establishing the industry standard for end-to-end interoperability of broadcast and interactive digital audio-visual information. Its published specifications, DAVIC 1.0-1.4, are backward compatible and form the foundation for commercial interactive multimedia experiences. Each specification is market-driven and developed where possible in close synergy with the products and work in progress of other standards-developing organizations. In addition, DAVIC 1.3.1 has been submitted as a Draft International Standard to ISO/IEC JTC 1 in order to establish this industry specification as a recognized international standard and to contribute to the international standards community. DAVIC's future goals are clear, and significant progress is being made on achieving TV anytime/anywhere as the next stage to full interactive multimedia services     

Delivering interactive services via a digital TV infrastructure

This article discusses an architecture for interactive service delivery to the home via the digital television (DTV) infrastructure in systems with and without return channels. This approach relies on a broadcast computing model adapted to suit the DTV environment. The model works even with low-cost user terminals, such as the basic DTV set-top boxes with limited computational and graphics capability and no local disk storage     

TOBASCO: an innovative approach for upgrading CATV fiber-coaxnetworks for broadband interactive services

To introduce broadband interactive services in a fiber-coax CATV network with high splitting ratio, a high-density wavelength multiplexing upgrading strategy in combination with conventional TDMA techniques is presented. It features flexible network reconfiguration via wavelength reassignment at the fiber terminating network units, a high interactive services capacity per user, and improved network scalability. On the fiber part of the network the interactive channels are carried in baseband, time-multiplexed (in ATM) in a number of wavelength channels. The article gives an overview of the most distinctive characteristics of TOBASCO. The system architecture as well as the evolutionary upgrade path are presented. The implications of the flexible wavelength allocation scheme on the network topology and, in particular, dynamic assignment strategies are analyzed. Finally, the field trial to be carried out in Gent is discussed     

数字电视中交互业务的分类及实现

对数字电视中的一些交互业务进行了讨论，并针对目前电视系统的特点提出了简单实用的实现交互数字广播的方法。     

Broadband interactive services and digital television at 42 GHz

This paper describes and evaluates the first results, from a trial under real conditions, of a wireless cellular interactive network at 42 GHz, for broadband services and digital (MPEG‐2) television, realized in the frame of an European Union program, in the area of Athens. The adopted system architecture and network configuration are described and technical data concerning the development of the interactive services are provided. The performance of the system is also evaluated. Copyright © 1999 John Wiley & Sons, Ltd.     

Videotex and interactive services on tree-and-branch cable TV networks

Interactive services on tree-and-branch cable TV systems in the U.K. have been rather slow to emerge. This has been partly due to the high cost of the customers' terminals but is also due to the difficulty of passing keyboard data, from the customers, back over the cable network to the head-end. This paper describes a new approach to these problems and shows that Videotex and other interactive services can be provided without major engineering changes to the network.     

Cross-cultural comparison of interactive streaming services: Evidence from Twitch

A cross-cultural study of interactive live streaming platforms was conducted to investigate emotional differences in communication behavior. We collected 10,432,423 chat messages from Twitch streams, and our analysis was twofold: (1) classifying viewers by their consumption behavior and (2) analyzing subscribers’ emote usage and emotional expressions. The results showed that there are significant differences in several linguistic and psychological dimensions of emotional expressions between Western and Eastern cultures. Along with these cultural differences, our study addresses the importance of encouraging the social interaction in Twitch for viewer engagement.     

Crosstalk in a fibre access network demonstrator carryingtelevision and interactive digital services

An optical access network is being constructed as part of the RACE programme to demonstrate the feasibility of providing both interactive broadband and television distribution services over a single, shared fibre to a residential subscriber. The interactive and distributive services will be transmitted in the 1.3 μm and 1.5 μm optical windows, respectively, of the fibre. To prevent crosstalk between the two services a wavelength division demultiplexer which gives adequate isolation between the two optical carriers must be provided at the subscriber receiver. Performance deterioration due to mutual crosstalk is calculated and measurement results presented. Theory and measurement show that the deterioration of the interactive signal caused by the distributive signal sets the most demanding isolation requirement. For an interactive signal penalty of 0.5 dB the isolation has to be 40 dB, which is at the limit of the performance achieved by commercially available wavelength division demultiplexers     

The use of session control in DAVIC to provide interactive multimedia services

This paper begins with an introduction to DAVIC, with particular reference to its objectives and plans. It then considers the split of the functional model into the three roles — service consumer system, delivery system and service provider system. Once the vertical split of the functional model has been considered the horizontal split into S1-S4 levels is covered. The paper then expands on the concepts of session and connection control through the use of the S2, S3 and S4 levels in the set-up, transfer and release of a user-to-network session and the end-to-end control of the user-to-user session. Finally, future plans/directions for DAVIC are considered, along with the adoption of Internet technologies within the DAVIC specifications.     

An early implementation of a DAVIC V1.0 system — use of dynamic connections for interactive multimedia services

Advances in networking technology and the provision of greater wide area bandwidths are the catalysts for the emergence of new broadband services in both the business and residential market. This is in turn producing new, more complex, business models involving service consumers, content providers, service brokers and network connectivity providers. Such business models require the underlying technology to enable sophisticated network signalling to set up, monitor and tear down connections reliably and in real time.This paper describes the evolution of a broadband call control demonstrator believed to be the first of its kind in the world to provide a practical realisation of the signalling required in such business models. It focuses on signalling and switch control and has developed into an end-to-end implementation of a Digital Audio Visual Council (DAVIC) V1.0 system.The evolution of the switch control and signalling architecture is described, showing where existing standards have been implemented to provide basic connectivity across an ATM network. Additional capabilities are built upon this platform through the adoption of emerging signalling concepts, such as session control, and application control using distributed object-oriented principles, for the access and control of a video-on-demand service.To further understand the evolutionary path for emerging consumer systems, the paper illustrates how work was undertaken to separate set-top box (STB) functionality into a set-top unit (STU) and a network interface unit (NIU), allowing easier access to future broadband network capabilities.     

Integration of interactive and distribution services: Impact on the network architecture and signalling

The integration of interactive and distribution services has an impact on both the architecture of the network and the signalling protocols. A configuration where both services are offered via ATM is discussed here. For multimedia services a layered service model is described. The impact of this layered model on the signalling is explained.     

Partial linear regression for speech-driven talking head application

Avatars in many applications are constructed manually or by a single speech-driven model which needs a lot of training data and long training time. It is essential to build up a user-dependent model more efficiently. In this paper, a new adaptation method, called the partial linear regression (PLR), is proposed and adopted in an audio-driven talking head application. This method allows users to adapt the partial parameters from the available adaptive data while keeping the others unchanged. In our experiments, the PLR algorithm can retrench the hours of time spent on retraining a new user-dependent model, and adjust the user-independent model to a more personalized one. The animated results with adapted models are 36% closer to the user-dependent model than using the pre-trained user-independent model.     

Intelligent satellites for interactive graphics

The spectrum of remote user stations with local processing ability, ranging from simple "smart" terminals to nearly self-sufficient intelligent systems called satellites, is considered. The emphasis is on the latter category, drawing on the authors' research on intelligent satellites for interactive graphics. The necessity of meeting a "critical intelligence threshold" criterion for the satellite is stressed, and some difficult problems and potential solutions in the division of labor between mainframe and satellite are briefly examined. It is hoped that many of the problems and solutions in satellite graphics apply to other areas such as network or satellite process control, experiment control, and signal processing.     

Adaptive algorithms for interactive multimedia

Modeling multimedia content by identifying semantically meaningful entities can be arduous because it's difficult to simulate human perception. However, by creating an algorithm to respond interactively to user preference, content-retrieval systems can become more efficient and easier to use.     

交互电视的组网技术

主要叙述交互电视传输网络总体结构、在线实时节目交换网络、非实时节目交换网络、用户接入网络，ＨＦＣ系统中上、下行信道频谱的划分，及回传信道协议。     

Synchronization for interactive multimedia presentations

When multimedia presentations allow users to make online adjustments such as reverse, skip, freeze-restart, and scale, maintaining temporal synchrony among several media streams becomes a complex modeling problem. Our approach uses dynamic extended finite-state machines for the task-an “actor” DEFSM for each medium and a “synchronizer” DEFSM to orchestrate them. This model achieves clear state-transition control flow and allows concise, precise specifications