David Jiménez

Stereoscopic 3D video quality assessment based on depth maps and video motion

In this paper, we propose techniques to assess the objective quality for stereoscopic 3D video content, related to motion and depth map features. An analysis has been carried out in order to understand what causes the generation of visual discomfort in the viewers eye when visualizing a 3D video. Motion is an important feature affecting 3D experience but is also often the cause of visual discomfort. Guidelines are obtained after applying the algorithm to quantify the impact over viewers experience when common cases happen, such as high motion sequences, scene changes with abrupt parallax changes, or complete absence of stereoscopy.

Architectures for Future Media Internet

Among the major reasons for the success of the Internet have been the simple networking architecture and the IP interoperation layer. However, the traffic model has recently changed. More and more applications (e.g. peer-to-peer, content delivery networks) target on the content that they deliver rather than on the addresses of the servers who (originally) published/hosted that content. This trend has motivated a number of content-oriented networking studies. In this paper we summarize some the most important approaches.

System architecture for enriched semantic personalized media search and retrieval in the future media internet

This article describes a novel system and its architecture to handle, process, deliver, personalize, and find digital media, based on continuous enrichment of the media objects through the intrinsic operation within a content oriented architecture. Our system and its architecture provide a solution that enhances the delivery, sharing, experience, and exchange by providing the methods to semantically describe contents with a multilingual-multimedia-multidomain ontology; annotate the content against this ontology; process the content and adapt it to the network and the network status, taking into account the user behavior and the user terminal device to consume the content; and enriching the content at any additional iteration or process, over a content-oriented architecture based on standardized interfaces. The article presents the architecture, modules, functionalities, and procedures, including the system application model to the future media Internet concepts for content-oriented networks.

Proposal for characterization of 3DTV video sequences describing parallax information

Recommendations such as P.910 suggests parameters TI (temporal information) and SI (spatial information) for characterizing video sequences for quality assessment. In this paper, we suggest two additional parameter based on disparity called SPI (spatial parallax information) and TPI (temporal parallax information) to characterize 3DTV video sequences for this purpose.

Subjective quality assessment in stereoscopic video based on analyzing parallax and disparity

Disparity may cause visual discomfort. Pairs of video sequences with different levels of parallax, both negative and positive, were presented together to the observers. The observers evaluated the cases in which visual discomfort occurred after visualizing the transition on each pair.

Definition of masks related to psychovisual features for Video Quality Assessment

Video Quality Assessment needs to correspond to human perception. Pixel-based metrics (PSNR or MSE) fail in many circumstances for not taking into account the spatio-temporal property of humans visual perception. In this paper we propose a new pixel-weighted method to improve video quality metrics for artifacts evaluation. The method applies a psychovisual model based on motion, level of detail, pixel location and the appearance of human faces, which approximate the quality to the human eyes response. Subjective tests were developed to adjust the psychovisual model for demonstrating the noticeable improvement of an algorithm when weighting the pixels according to the factors analyzed instead of treating them equally. The analysis developed demonstrates the necessity of models adapted to the specific visualization of contents and the model presents an advance in quality to be applied over sequences when a determined artifact is analyzed.

Design of a platform for assessing multimedia advertising content consumption with mobile devices validation

Multimedia advertising content needs to be assessed before campaign to assure its future success. Content consumption techniques are used to identify users interest through a determined content, but it needs effective validation. This paper describes the design of a two-fold analysis of video consumption implemented on EPSIS platform to measure users interest. The platform consists in a web interface for video visualization which executes an algorithm for automatic validation of users consumption, and a mobile application which subsequently enables users to assess the video content previously visualized. The video portfolio featured in our platform corresponds to advertising content and social media, which has special characteristics of length and complete meaning and is easier to be assessed than longer contents such as documentary or films. After developing subjective tests with a collection of observers, the mobile application allows to demonstrate the validation of the algorithm. The platform succeeds in validation of advertising contents reducing time and cost derived from the evaluation process.

Multimedia Source Management for Remote and Local Edition Environments

This paper aims to detail an innovative multimedia edition system. A special functionality provides this solution with different ways of managing audiovisual sources. It has been specially designed for media centralized environments dealing with large files and groups of users that access contents simultaneously for editing and composing. Mass media headquarters or user communities can take advantage of the two working modes, which allow online and offline workflows. The application provides a user edition interface, audiovisual processing and encoding based on GPL tools, communication via SOAP between client and server, independent and portable edition capabilities and easy adaptable source handling system for different technologies.

Tiling effect in quality assessment for high definition digital television

Although in the past decades bandwidth capacities have increased in existing networks, video compression techniques are still essential for managing high bit rates required by video services, especially those related with the trends on high definition video services. Using compression implies in most cases lossy processes that, in addition to reduce average video quality, create undesirable errors called artifacts. The treatment and removal of these artifacts from video sequences is a primary goal in nowadays coding standards. One of the most common and perceptually annoying artifacts is called tilling. Unwillingly produced by many digital coding systems, such as H.264, its particular treatment is a new investigation line that is described deeply in this paper.