Paulo Villegas

Perceptually-weighted evaluation criteria for segmentation masks in video sequences

In order to complement subjective evaluation of the quality of segmentation masks, this paper introduces a procedure for automatically assessing this quality. Algorithmically computed figures of merit are proposed. Assuming the existence of a perfect reference mask (ground truth), generated manually or with a reliable procedure over a test set, these figures of merit take into account visually desirable properties of a segmentation mask in order to provide the user with metrics that best quantify the spatial and temporal accuracy of the segmentation masks. For the sake of easy interpretation, results are presented on a peaked signal-to-noise ratio-like logarithmic scale.

Music recommendations with temporal context awareness

We present a system capable of recommending music playlists that take into account the temporal context of the user, i.e. they select user preferences as learned for the concrete time situation of the request.

A model for adapting 3D graphics based on scalable coding, real-time simplification and remote rendering

Most current multiplayer 3D games can only be played on dedicated platforms, requiring specifically designed content and communication over a predefined network. To overcome these limitations, the OLGA (On-Line GAming) consortium has devised a framework to develop distributive, multiplayer 3D games. Scalability at the level of content, platforms and networks is exploited to achieve the best trade-offs between complexity and quality.Most current multiplayer 3D games can only be played on dedicated platforms, requiring specifically designed content and communication over a predefined network. To overcome these limitations, the OLGA (On-Line GAming) consortium has devised a framework to develop distributive, multiplayer 3D games. Scalability at the level of content, platforms and networks is exploited to achieve the best trade-offs between complexity and quality.

AN ENVIRONMENT FOR EFFICIENT HANDLING OF DIGITAL ASSETS

The proliferation of digital media assets, and particularly their easy accessibility over open networks such as the Internet, has raised challenging issues regarding management, delivery, search, retrieval and ownership protection of video content. The rapid expansion of E-commerce services and the increased distribution of digital assets over fixed and wireless networks have generated an urgent need for technologies able to deliver high quality services to content creators, providers and end users. While end-users expect easy access to digital content using query structures natural and close to human concepts, content creators and providers are looking for efficient distribution systems capable of protecting digital content and tracing illegal copies. The BUSMAN project is designing and implementing an efficient system for understanding, delivery and querying of video from large databases, fulfiling the needs of content creators, providers and end user linked by heterogeneous networks while employing and enhancing multimedia standards such as MPEG-7 and MPEG-21. This paper is organized as follows. Section 2 reviews related activities in the field of digital content, notably indexing, retrieval and copyright management. The BUSMAN approach to content management is then outlined in section 3, which is followed by an overview of the system architecture in section 4. The paper concludes in section 5 with the promise of a functional demonstrator in due course.

3D game content distributed adaptation in heterogeneous environments

Most current multiplayer 3D games can only be played on a single dedicated platform (a particular computer, console, or cell phone), requiring specifically designed content and communication over a predefined network. Below we show how, by using signal processing techniques such as multiresolution representation and scalable coding for all the components of a 3D graphics object (geometry, texture, and animation), we enable online dynamic content adaptation, and thus delivery of the same content over heterogeneous networks to terminals with very different profiles, and its rendering on them. We present quantitative results demonstrating how the best displayed quality versus computational complexity versus bandwidth tradeoffs have been achieved, given the distributed resources available over the end-to-end content delivery chain. Additionally, we use state-of-the-art, standardised content representation and compression formats (MPEG-4 AFX, JPEG 2000, XML), enabling deployment over existing infrastructure, while keeping hooks to well-established practices in the game industry.

Recursive partitional-hierarchical clustering for navigation in large media databases

We present in this document a tool for automatic clustering of repositories of tagged media items (images, videos) and a 3D visualization interface to enable interactive browsing of repository contents based on the generated clusters.

A User-Centred System for End-to-End Secure Multimedia Content Delivery: From Content Annotation to Consumer Consumption

The paper discusses the current status of progress of the on-going EU IST BUSMAN project (Bringing User Satisfaction to Media Access Networks), which now approaches the milestone of its 2nd year running. The issues explained include the motivation and approaches behind the design of its client-server system architecture for effective data flows handling, the progress in the implementation of the proposed server system functionalities, and the advanced video processing algorithms investigated and adopted. A fully functional client-server system for video content management, search and retrieval for both professional use scenarios and customers with either fixed or wireless network connections is expected to be demonstrable by year end of 2004.

Bringing user satisfaction to media access: the IST BUSMAN Project

Interactive and seamless access to video content is facilitated by technology that is able to annotate and retrieve media data efficiently and automatically with the minimal human interventions. Media should be accessible by intended users quickly and independent of the database size, regardless of the homogeneous or heterogeneous nature of the delivery channels or the user computing platform. These requirements are driving research and development efforts in the European project BUSMAN; in which a system for efficient annotation, seamless delivery of and access to video components across heterogeneous channels is being developed. The BUSMAN system architecture is based on the needs and expectations of two types of users: content providers and end users. In this paper an overview of the BUSMAN system is presented and its main functionalities are described.

My personal media entertainer: context-adaptive content recommendation and delivery

We describe here a system oriented towards personalized selection and delivery of heterogeneous multimedia content. It is designed to go along with the user during the whole day seamlessly and provide on demand delivery of relevant multi-modal content, stemming from diverse sources. A set of specially designed recommendation engines provides personalization adapted to the instantaneous context of the user. We describe the overall architecture and usability principles of the system, and subsequently we focus in detail on some of its subsystems.

General approach to output rate control in video coding

This paper focuses the video coding for real time applications and its transmission over synchronous or asynchronous networks, with special interest in ATM (asynchronous transfer mode) switching and multiplexing. Video coders compress the information of a sequence producing a bit stream whose rate, in real time applications, should be controlled to fit the transmission resources. In this work we analyze the main control proposals from a general and comprehensive point of view, pointing out the observed variables, the prediction mechanisms, the action and periodicity of the control. The control action is to switch between different quantization modes. Actually, the coder must decide before coding a unit. A prediction of the data volume to be generated is helpful to avoid ungraceful degradation. The tradeoff in the periodicity of the action is the other key point. We propose a general strategy, compatible with MPEG standards, that is the real buffer evolution shaping. We observe the real buffer and impose a desired level variation. The buffer shaping unit can be a frame, slice, or macroblock. A method of prediction of the data volume to be produced in a unit is proposed. Using the proposed approach we study constant quality and variable bit rate coding, well suited for asynchronous networks. We compare the buffer evolution and the quality of coding under different strategies. In ATM environments the policing functions are taken into account as restrictions to be respected. methods to adapt coding with known policing functions are proposed.