Real-Time Interactive MPEG-4 System Encoder Using a Cluster of Workstations

MPEG-4 currently being finalized by the Moving Pictures Experts Group of the ISO is a multimedia standard. MPEG-4 aims to support content-based coding of audio, text, image, and video (synthetic and natural) data, multiplexing of coded data, as well as composition and representation of audiovisual scenes. One of the most critical components of an MPEG-4 environment is the system encoder. An MPEG-4 scene may contain several audio and video objects, images, and text, each of which must be encoded individually and then multiplexed to form the system bitstream. Due to its flexible features, object-based nature, and provision for user interaction, MPEG-4 encoder is highly suitable for a software-based implementation. A full-scale software-based MPEG-4 system encoder with real-time encoding speed is a nontrivial task and requires massive computation. We have built such an encoder using a cluster of workstations collectively working as a virtual parallel machine. Parallel processing of MPEG-4 encoder needs to be carried out carefully as objects may appear or disappear dynamically in a scene. In addition, objects may be synchronized with each other. User interactions may also prohibit a straightforward parallelization. We propose a modeling methodology that captures the spatio-temporal relationship between various objects and user interaction. We then propose a number of scheduling algorithms that periodically allocate MPEG-4 objects to multiple workstations ensuring load balancing and synchronization requirements among multiple objects. Each scheduling algorithm has its own performance and complexity characteristics. The experimental results, while showing real-time encoding rates, exhibit tradeoffs between load balancing, scheduling overhead cost, and global performance

Interactive television based on insertion of hypermedia information on MPEG standard video

Orientador : Yuzo IanoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: TV interativa é uma das grandes promessas no campo dos aparelhos eletrônicos para o consumidor. Entretanto, ainda não há um padrão definitivo para implementar esse novo tipo de dispositivo. Por isso, pesquisas são conduzidas para desenvolver um padrão barato, simples e, ao mesmo tempo, o mais funcional possível. Seguindo essa linha de raciocínio, este trabalho propõe um modelo para a inserção de informações hipermídia em vídeos em um padrão amplamente conhecido e já implementado nos televisores digitais atuais: o padrão MPEG. O modelo proposto é baseado na elaboração de um conceito próprio de hipervídeo, no qual são embutidas referências a informações complementares ao conteúdo sendo exibido. Tais referências e as coordenadas dos objetos em cena, que atuam como âncoras para as informações complementares, formam o que se define como informações hipermídia. Além da concepção do modelo, este trabalho também apresenta uma prova de conceito para demonstrar a viabilidade das ideias aqui descritasAbstract: The interactive TV is one of the great promises on Consumer Electronics field. However, there is no definitive standard to implement this new kind of device. For this reason, researches are conducted to develop a standard cheap, simple, and also the most functional as possible. Tracing this reasoning, this work proposes a model to insert hypermedia information on videos in a widely known and already implemented standard in current digital television sets: the MPEG standard. The proposed model is based on the creation of a particular concept of hypervideo, which references to complementary information are embedded on the content being presented. Such references and the coordinates of the objects in scene, which act as anchors to complementary information, both form what is defined as hypermedia information. Beyond the conception of the model, this work also presents a concept proof to demonstrate the viability of the ideas here depicted.DoutoradoTelecomunicações e TelemáticaDoutor em Engenharia Elétric