César A. C. Teixeira

Watch-and-comment as a paradigm toward ubiquitous interactive video editing

The literature reports research efforts allowing the editing of interactive TV multimedia documents by end-users. In this article we propose complementary contributions relative to end-user generated interactive video, video tagging, and collaboration. In earlier work we proposed the watch-and-comment (WaC) paradigm as the seamless capture of an individuals comments so that corresponding annotated interactive videos be automatically generated. As a proof of concept, we implemented a prototype application, the WaCTool, that supports the capture of digital ink and voice comments over individual frames and segments of the video, producing a declarative document that specifies both: different media stream structure and synchronization. In this article, we extend the WaC paradigm in two ways. First, user-video interactions are associated with edit commands and digital ink operations. Second, focusing on collaboration and distribution issues, we employ annotations as simple containers for context information by using them as tags in order to organize, store and distribute information in a P2P-based multimedia capture platform. We highlight the design principles of the watch-and-comment paradigm, and demonstrate related results including the current version of the WaCTool and its architecture. We also illustrate how an interactive video produced by the WaCTool can be rendered in an interactive video environment, the Ginga-NCL player, and include results from a preliminary evaluation.

CastFlow: Clean-slate multicast approach using in-advance path processing in programmable networks

Multipoint communication is an important requirement for many types of applications such as videoconferencing, IPTV and online radio. However, the division of Internet in autonomous systems hinders the widespread adoption of traditional multicast protocols, which, for using distributed algorithms, delay the group control events processing. This paper proposes a multicast clean-slate approach logically centralized based on programmable networks and anticipated processing for all routes from each possible source, aiming to reduce event delays. A prototype was implemented based on OpenFlow technology. In addition, extensive evaluation was performed and results show promising delays comparable to the requirements of multipoint applications.

A social approach to authoring media annotations

End-user generated content is responsible for the success of several collaborative applications, as it can be noted in the context of the web. The collaborative use of some of these applications is made possible, in many cases, by the availability of annotation features which allow users to include commentaries on each others content. In this paper we first discuss the opportunity of defining vocabularies that allow third-party applications to integrate annotations to end-user generated documents, and present a proposal for such a vocabulary. We then illustrate the usefulness of our proposal by detailing a tool which allows users to add multimedia annotations to end-user generated video content.

Ubiquitous services in home networks offered through digital TV

This paper presents some industry proposals for the interoperability between devices in home environments and reports our efforts on exploiting the computational aspects related to the offer of ubiquitous services in the context of household environments. It explores the communication ability between the set-top box and other devices of household environments and of personal use through the development of a software module for transparent replication of audiovisual digital TV content, in home networks based on Universal Plug and Play (UPnP#8482;) / Digital Living Network Alliance (DLNA). The implementation was carried out on an environment emulating a set-top box according to the Brazilian standard for DTV.

WebNCL: a web-based presentation machine for multimedia documents

Presentation machines for multimedia declarative languages especially the ones related with Interactive Digital TV (iDTV) and Internet Protocol TV (IPTV) are usually embedded in devices and strongly coupled with the platforms when native code and API for the devices platform are used. Since much of the complexity to implement presentation machines lies on presenting and controlling different types of media (video, audio, image, text), and given that most of the modern browsers natively support those requirements, it becomes interesting to implement presentation machines using Web technologies to reduce their coupling with platforms. In this paper we discuss the advantages of a presentation machine for declarative multimedia languages implemented on top of Web technologies. As a proof of concept we implemented the WebNCL, a lightweight NCL presentation machine based on the web technologies stack (HTML 5/ JavaScript/ CSS). By using WebNCL, NCL documents can be presented in any device that has a HTML5 compatible browser, such as tablets, smartphones, smart TVs and PCs.

Semantic Web Services Discovery and Composition: Paths Along Workflows

Semantic Web Services discovery and composition: paths along workflows Web Services allow the composition of new services on top of existing, partial ones. Using standard languages, Semantic Web Services can provide the description of their input parameters and preconditions for execution, as well as the output and effects of their execution. The availability of such descriptions demand the investigation of systematic approaches for the composition of Web Services based on their description. After presenting our approach for service discovery, we detail our proposal for modeling the composition problem using graphs. Next, we present the algorithm we implemented for the composition of Web Services, detailing the cost-based policy underlying our graph-based model. We also present the results of experiments we executed based on artificial data describing Web Services.

Ubiquitous Interactive Video Editing Via Multimodal Annotations

Considering that, when users watch a video with someone else, they are used to make comments regarding its contents --- such as a comment with respect to someone appearing in the video --- in previous work we exploited ubiquitous computing concepts to propose the watching-and-commentingauthoring paradigm in which a users comments are automatically captured so as to automatically generate a corresponding annotated interactive video. In this paper we revisit and extend our previous work and detail our prototype that supports the watching-and-editingparadigm, discussing how a ubiquitous computing platform may explore digital ink and associated gestures to support the authoring of multimedia content while enhancing the social aspects of video watching.

Inkteractors: interacting with digital ink

Digital inking systems accept pen-based input from the user, process and archive the resulting data as digital ink. However, the reviewing techniques currently available for such systems are limited. In this paper we formalize operators that model the user interaction during digital ink capture. Such operators can be applied in situations where it is important to have a customized view of the inking activity. We describe the implementation of a player that allows the user, by selecting the desired operators, to interact with digitally annotated documents while reviewing them.

Collaborative synchronous video annotation via the watch-and-comment paradigm

Earlier work has described the WaCTool, which allows a user to perform multimodal annotations (text, digital ink and audio comments) and edit operations on a linear video, producing an interactive video as a result. The fact that the prototype had been extended to allow users to use an integrated chat and share resources in a peer-to-peer-based environment lead users to identify an opportunity to share digital ink notes. The work reported in this paper aims at evaluating a prototype designed to allow the synchronous collaborative editing comments on top of video frames selected by users for annotation. We discuss our aim in allowing this new form of collaboration and present the results of evaluation using four complementary methods: think aloud, heuristics, cognitive walkthrough and questionnaires.

User-media interaction with interactive TV

Watching TV is a practice many people enjoy and feel comfortable with. We propose the capture of the user interaction while interacting with a remote control to watch TV: such detailed information is most valuable to many applications and services. We discuss our proposed approach in the context of the Brazilian Interactive Digital TV platform.