This paper presents and discusses the internal operation of NCLSC (NCL Stereo Converter): a tool to convert a 2D interactive multimedia application annotated with depth information to a stereoscopic-multimedia application. Stereoscopic-multimedia applications are those that codify both the left-eye and right-eye views, as required by stereoscopic 3D displays. NCLSC takes as input an NCL (Nested Context Language) document and outputs an NCL stereoscopic application codified in side-by-side or top-bottom format (both common input formats for 3DTV sets). NCL is the declarative language adopted in most Latin America countries for terrestrial digital TV middleware systems and the ITU-T H.761 Recommendation for IPTV services. However, the proposed approach is not restricted to NCL and can be used by other languages. The depth annotation allows for positioning each 2D graphical component in a layered (2.5D or 2D+depth) user interface. It is used by NCLSC to compute the screen parallax (offset) between the graphical elements in the left and right views of the resulting stereoscopic application. When the resulting application is presented on stereoscopic 3D displays, such screen parallax induces retinal disparity, which creates the illusion of floating flat-2D graphical elements. NCLSC does not require any additional native middleware support to run in currently available 3D-enabled TV sets. Moreover, NCLSC can adapt, at run-time, the output application to different display sizes, viewer distances, and viewer preferences, which are usually required for a proper balance between artistic effects and user experience.

This paper presents an architecture for monitoring the presentation of multimedia declarative applications, providing feedback about variables states, object properties, media presentation times, among others. Monitoring tools that follow the proposed architecture are able to detect if visual problems are being caused by programming errors or by player malfunctioning. The architecture presents a communication protocol designed to be independent of the declarative language used in the development of multimedia applications. The main goal is to provide an open and generic architecture that can assist multimedia application authors and presentation engine developers. As an example of the architecture use, the paper also presents a monitoring tool integrated into a graphical user interface developed for the ITU-T reference implementation of the Ginga-NCL middleware.

Multi-head setups are commonly used to enhance productivity and to increase the screen area of multimedia presentations. To support the latter, multimedia systems must have access to information about the display arrangement and about bezels and gaps between displays, to calculate the multi-head total resolution and to define the active exhibition area. Existent solutions oblige users to know the details of the display arrangement, and to map manually the logic display arrangement into the physical one. Even when they provide some features to easy this mapping, users have to pay attention on hardware details, and are limited to predefined display arrangements. In addition, users have to adhere to try-and-error calculations to achieve better results for setting bezel and gap values. This paper presents a mechanism to support multimedia presentations on multi-head setups that cracks the limitations found in the existent systems. The proposed mechanism has been integrated with the reference implementation of Ginga, the ITU-T H.761 IPTV middleware. However, the solution is generic and can be used with other multimedia systems.

This paper discusses how multimedia languages and players can handle multiple time bases in supporting inter-media synchronization with interleaved media contents transmitted as unsolicited streams (pushed data). More specifically, we are interested in inter-media synchronization defined by causal/constraint relationships. Unsolicited interleaved media-contents are usual in digital TV systems, in particular in broadcast TV, in which adverts are inserted into programs transmitted sequentially. Although some existing middleware systems address the problem, their solutions have limitations. This work proposes an alternative approach providing high-level abstractions that hide or minimize the complexity of dealing with interleaved media-content as part of hypermedia applications. The proposal has been incorporated in the Nested Context Language (NCL) and in its player, the main component of the Ginga digital TV middleware. However, despite using NCL as an example, the proposal has a broader spectrum and can be adapted and used in other languages and respective engines.

This paper presents a model for the specification of hierarchical control of focus and input events in hypermedia applications that may contain atomic objects and nested compound objects. A proposal to solve the problems of declarative languages for both Web domain and Digital TV domain is described. The model proposed by us is part of the Digital TV profiles of NCL language specification. The model, however, may be extended to be used in other declarative languages. The model was incorporated into the Ginga reference implementation. NCL and Ginga are part of ITU-T Recommendation for IPTV services and ISDB-T standards (International Standard for Digital Broadcasting — Terrestrial).

Templates have been used to engage non-expert multimedia authors as content producers. In template-based authoring, templates with most of the relevant application logic and application constraints are developed by experts, who must also specify the template semantics, report which are the required gaps to be filled in, and how to do so. Filling template's gaps is the single task left to inexperienced users to produce the final applications. To do that, they usually must understand the padding instructions reported by template authors and learn some specific padding language. An alternative is using specific GUI components created specifically to each new developed template. This paper proposes a semi-automatic generation of GUI Wizards to guide end(-user) authors to create multimedia applications. The wizard can be tuned to improve the communication between the template author and the template end user, and also if the template specification is not complete. Many successful trial cases show that the generated wizards are usually simple enough to be used by non-experts. The contributions coming from this paper is not constrained to any specific template language or final-application format. Nevertheless, aiming at testing the proposal it was instantiated to work with TAL (Template Authoring Language) whose template processors can generate applications in different target languages.

The proliferation of multimedia narratives has contributed to what is known as the "crisis of choice", which demands a much more active participation on the part of the user to consume multimedia content. To address this issue, a strategy is to offer users efficient search mechanisms, sometimes based on ontologies. However, one may argue that such mechanisms are often based on abstractions that do not adequately capture the essential aspects of multimedia narratives. This paper proposes a conceptual model to specify multimedia narratives that overcomes this limitation. The model is based on the notion of event and is therefore called Nested Event Model (NEMo). The paper also includes a complete example to illustrate the use of the model.

SUMMARY Ginga is the middleware of the Japanese‐Brazilian terrestrial digital TV (DTV) system, ISDB‐TB, and also the ITU Telecommunication Standardization Sector (ITU‐T) Recommendation for Internet Protocol television services. Ginga supports NCL (Nested Context Language) applications in its declarative environment (Ginga‐NCL) for which we devise an architecture for plug‐in integration. This paper focuses on this plug‐in architecture and its innovative solutions, detailing the plug‐in API, life‐cycle and control model, besides discussing how the architecture can be extended to other software systems, in particular to other DTV middleware systems. In the paper, we show how Ginga‐NCL can embed other declarative language engines. On the other hand, we also extend an HTML browser to allow it to embed Ginga‐NCL. This proof‐of‐ concept is important because NCL and HTML players are not only the most common players found in DTV middleware systems but also because they are ITU Telecommunication Standardization Sector Recommendations for terrestrial and Internet Protocol television services (NCL and Broadcast Markup Language (BML)/Lightweight Interactive Multimedia Environment (LIME)). Therefore, this proof‐of‐concept also provides a contribution to DTV middleware interoperability. Copyright © 2012 John Wiley & Sons, Ltd.

TAL (Template Authoring Language) is a specification language for hypermedia document templates. Templates describe application families with structural and semantic similarities. In TAL, templates not only define design patterns that applications must follow, but also constraints on the use of these patterns. A template must be processed together with a padding document giving rise to a new document in some specification language, called target language. TAL supports the description of templates independently of the languages used to specify target and padding documents. Usually a specific processor is required for each target language and for each padding document used. This paper concerns TAL processors. However, we should note that the proposal can be easily extended to any other solution used to define templates. Any pattern language and any language used to define constraints could be used instead of TAL. The TAL processor architecture is general and it is discussed when presenting the processor framework. As an instantiation example, an implementation of a TAL Processor targeting NCL (the declarative language of Ginga DTV middleware) is examined, and also another one targeting HTML-based middleware. The use of wizards for defining padding documents is also discussed in the examples of the proposed architecture instantiation.

This paper deals with the generation of dynamic hypermedia applications whose content and behavior their authors may not be able to predict a priori, but which must conform to a strict set of explicitly defined constraints. In the paper, we show that it is possible to establish an architecture configuration to be followed by this special kind of dynamic applications. In the proposed architecture, templates are responsible for specifying the design patterns and the constraints to be followed. Some alternatives for distributing (from the client side to the server side) the components that comprise the architecture are discussed, and one of them is used to exemplify an instantiation of the architecture. In the instantiation, TAL (Template Authoring Language) is used to define templates. In TAL, templates are open-compositions, that is, especial set of patterns for compositions, whose content must obey some explicitly defined constraints. The paper also shows how the architecture instantiation could be used to build dynamic digital TV applications.

The Ginga-NCL environment is responsible for the presentation of declarative (NCL) applications on the Brazilian Digital TV System (SBTVD), and it is also the ITU-T H.761 Recommendation for IPTV middleware. Lua is the scripting language of NCL. ITU-T H. 760 series also defines two sets of NCLUA API for the development of IPTV applications: the Core and the Extended API. The Core comprises the basic NCLua API, which are part of the Ginga-NCL original specification for the Brazilian terrestrial DTV system. The Extended aims to provide other relevant functionalities incorporating some of the features commonly present on other imperative environments. LuaTV is part of the draft specification for the NCLua Extended API. LuaTV features are divided in four functional categories: metadata, with functionalities related to the accessing Digital TV metadata information; security, providing mechanisms for encrypting and authenticating data; HAN, offering high-level access to resources commonly available on home networks; and widget, aimed at graphical support to applications. This paper presents the current LuaTV specification and its implementation.

This paper focuses on the support provided by NCL (Nested Context Language) to relate objects with imperative code content and declarative hypermedia-objects (objects with declarative code content specifying hypermedia documents). NCL is the declarative language of the Brazilian Terrestrial Digital TV System (SBTVD) supported by its middleware called Ginga. NCL and Ginga are part of ISDB standards and also of ITU-T Recommendations for IPTV services.

Nested Context Language (NCL) is the declarative language of the Brazilian Terrestrial Digital TV System. NCL is part of ISDB (International Standard for Digital Broadcasting) standards and also the ITU-T Recommendation H.761 for IPTV services. This paper presents, discusses, and illustrates the NCL hierarchical control model for multiple exhibition device support. Based on this model, multiple devices are orchestrated to run a DTV application in cooperation. Two types of multiple device exhibitions are distinguished. Those where the same content is shown in a set of devices under a unique control, and those where content is under each individual device control, working completely independent. In this last case, depending on viewer interactions, the resulting presented content can differ from a device to another. Examples of NCL applications using both options are presented and discussed.

Document engineering is the computer science discipline that investigates systems for documents in any form and in all media. As with the relationship between software engineering and software, document engineering is concerned with principles, tools and processes that improve our ability to create, manage, and maintain documents ( http://www.documentengineering.org ). The ACM Symposium on Document Engineering is an annual meeting of researchers active in document engineering: it is sponsored by ACM by means of the ACM SIGWEB Special Interest Group. In this editorial, we first point to work carried out in the context of document engineering, which are directly related to multimedia tools and applications. We conclude with a summary of the papers presented in this special issue.

Intermedia synchronization is related with spatial and temporal relationships among media objects that compound a DTV application. From the server side (usually a broadcaster's server or a Web Server) to receivers, end-to-end intermedia synchronization support must be provided. Based on application specifications, several abstract data structures should be created to guide all synchronization control processes. A special data structure, a labeled digraph called HTG (Hypermedia Temporal Graph) is proposed in this paper as the basis of all other data structures. From HTG, receivers derive a presentation plan to orchestrate media content presentations that make up a DTV application. From this plan other data structures are derived to estimate when media players should be instantiated and when data contents should be retrieved from a DSM-CC carousel or from a return channel. If the return channel provides QoS support, another data structure is derived from the presentation plan, in order to determine when resource reservation should take place. For content pushed by broadcasters, HTG is used in the server side as the basis for building the carousel plan, a data structure that guides the order and frequency that media objects should be broadcasted.

Textual programming languages have proven to be difficult to learn and to use effectively for many people. For this sake, visual tools can be useful to abstract the complexity of such textual languages, minimizing the specification efforts. In this paper we present a visual approach for high level specification of spatiotemporal relations. In order to accomplish this task, our visual representation provides an intuitive way to specify complex synchronization events amongst media. Finally, to validate our work, the visual specification is mapped to NCL (Nested Context Language), the standard declarative language of the Brazilian Terrestrial Digital TV System.

The research area of interactive digital TV is in the midst of a significant revival. Unlike the first generation of digital TV, which focused on producer concerns that effectively limited (re)distribution, the current generation of research is closely linked to the role of the user in selecting, producing, and distributing content. The research field of interactive digital television is being transformed into a study of human-centered television. Our guest editorial reviews relevant aspects of this transformation in the three main stages of the content lifecycle: content production, content delivery, and content consumption. While past research on content production tools focused on full-fledged authoring tools for professional editors, current research studies lightweight, often informal end-user authoring systems. In terms of content delivery, user-oriented infrastructures such as peer-to-peer are being seen as alternatives to more traditional broadcast solutions. Moreover, end-user interaction is no longer limited to content selection, but now facilitates nonlinear participatory television productions. Finally, user-to-user communication technologies have allowed television to become a central component of an interconnected social experience. The background context given in this article provides a framework for appreciating the significance of four detailed contributions that highlight important directions in transforming interactive television research.

In some hypermedia system applications, like interactive digital TV applications, authoring and presentation of documents may have to be done concomitantly. This is the case of live programs, where not only some contents are not known a priori, but also some temporal and spatial relationships, among program media objects, may have to be established after the unknown content definition. This paper proposes a method for hypermedia document live editing, preserving not only the presentation semantics but also the logical structure semantics defined by an author. To validate this proposal, an implementation has been done for the Brazilian Digital TV System, which is also presented.

This paper proposes new features for presenting and authoring MPEG-4 programs using the NCL language. On one hand, the language allows to define relationships among objects inside an MPEG-4 scene and external media objects, including objects in other MPEG-4 scenes. Relationships with several different semantics will also be allowed other than those defined by the standard. An NCL hypermedia formatter integrated with MPEG-4 players supports these new introduced features. On the other hand, the paper also takes advantage of the NCL composite-node template concept, to add new authoring facilities when specifying MPEG-4 documents using the XMT-O language.

This paper presents the main new features of Nested Context Language (NCL) version 2.0. NCL 2.0 is a modular and declarative hypermedia language, whose modules can be combined to other languages, such as SMIL, to provide new facilities. Among the NCL 2.0 new features, we can highlight the support for handling hypermedia relations as first-class entities, through the definition of hypermedia connectors, and the possibility of specifying any semantics for a hypermedia composition, using the concept of composition templates. Another important goal of this paper is to describe a framework to facilitate the development of NCL parsing and processing tools. Based on this framework, the paper comments several implemented compilers, which allow, for instance, the conversion of NCL documents into SMIL specifications.

The increasing number of multimedia applications has motivated the construction of platforms with end-to-end quality of service (QoS) support. This work proposes the use of Wright architecture description language (ADL) in the QoS provisioning domain, as the basis for the formal verification of QoS system properties. To smooth this task, the LindaQoS domain-specific language was designed as a high-level notation for the specification of resource (QoS) orchestration. As a result of this approach, we expect that designers can define clear and unambiguous instantiated platforms, with support to multimedia application implementations, in a reduced development time.

The development of hypermedia/multimedia systems requires the implementation of an element, usually known as formatter, which is in charge of receiving the specification of a document (structure, media-object relationships and presentation descriptions) and controlling its presentation. The process of controlling and maintaining the presentation of a hyperdocument with an output of acceptable quality is a QoS orchestration problem, which needs to be treated by formatters in two related levels: the inter media-object and the intra media-object orchestration. This paper aims at discussing the issues associated to QoS provisioning in hypermedia systems, focusing on the design and implementation of formatters. We propose a QoS framework for hypermedia formatters based on a generic quality of service model for communication environments. The paper also comments the experience obtained in the framework instantiation for the HyperProp system formatter.

This paper proposes XConnector, a language for the creation of complex hypermedia relations with causal or constraint semantics. XConnector allows the definition of relations independently of which resources are related. Another feature is the specification of relation libraries, providing reuse in relationship definition. The main goal is to improve linking languages or the linking modules of hypermedia authoring languages in order to provide multimedia synchronization capabilities using links. Following this direction, an extension to W3C XLink is proposed, incorporating XConnector facilities.

This paper presents a detailed comparison between the structural elements and definitions provided by Hypermedia Authoring Languages and Architecture Description Languages (ADL). ADLs are formal languages that can be used for representing a software architecture. Although it may look trivial to make a direct correspondence between ADL and hypermedia structural entities, such as components to nodes and connectors to links, interesting differences can be identified when observing them more closely. Based on the comparison results, a structural meta-model that can be specialized for use in both domains is proposed. Furthermore, the paper also presents an example of how the meta-model can be used for describing hypermedia document structures, showing how some features found in ADLs can be applied to hypermedia authoring languages. Our final goal is to integrate the contributions of document engineering and software architecture engineering and take advantage of the advances of one area in the other one. The current paper is the first step towards this direction.

This paper proposes an approach for representing and programming QoS functions in communication systems. It presents a model that gives adequate support for defining: (i) communication environments and their adaptation mechanisms, and (ii) frameworks that delineate QoS-specific abstractions that appear within any communication environment.

Hypermedia authoring tools usually suffer ikom a lack of validation capabilities that would make it possible to check a document against temporal inconsistencies.The document design methodology proposed in the paper overcomes this problem by translating a high-level model of an hypermedia document into a RT-LOTOS formal specificatio~on which standard reachability analysis may be applied for verification purposes.The propod approa~extends an early work to verify both intrinsic and extrinsic temporal consistency properties of an hypermedia documenti 1.1

The paper proposes a visualization tool for the structure of World-Wide Web documents using fisheye-view techniques. Besides helping user navigation, this graphical browser may play an important role in Web information searching. In order to build structural views more efficiently, a set of rules for Web-site authoring, based on nested composition concepts, are proposed to help logically organizing documents.

The paper presents a methodology by which documents authored with the Nested Context Model (NCM) are automatically translated into a RT-LOTOS specification. The latter is then checked against intrinsic and extrinsic consistencies using standard RT-LOTOS reachability analysis.

LANBRETA-GCS, an LAN-based real-time audio-graphics teleconferencing system, is presented. The environment which the system is being implemented is introduced, and the specification decisions are justified. Although LANBRETA-GCS is being implemented in a local area network environment, utilizing an IBM token ring and the functions of DOS, NETBIOS, and the PC LAN program, its implementation is much more general. The organization of the system, to handle conferencing groups or individual messages, is described.>