On leave from Telecom ParisTech

Starting today and for a period of 6 months, I’ll be on leave from Telecom ParisTech, back some time in April 2012. I’ll check my emails from time to time but don’t expect rapid answers. I’ll still be working on some of my favorite multimedia topics but from a different place (far from Paris). So, you may find me in some meeting or have some emails from me.

For matters related to Telecom ParisTech or GPAC, please contact my colleagues from Telecom ParisTech. For other matters, you can contact me on Twitter or by private emails.

SVG Folded Maps in 3D environments

Some time ago, Erik Dahlström made an SVG version of a folded Google Map. That map uses images, masks and clippers to produce a 3D effect. It is adapted from an HTML/CSS/SVG folded map. I found both pretty cool but I thought I could make another interesting version using 3D tools. Here it is. It’s a mix of 3D shapes onto which I map an SVG content retrieved from OpenStreeetMap. Unfortunately, there’s no shading but interestingly the map folds/unfolds with animations. It’s written in VRML/MPEG-4 BIFS textual language. I guess it could easily be made with WebGL as well (and has been done in a very nice demo by Adobe with CSS Shaders). It works only in GPAC but you can see a resulting video here:




SVG RadialGradients

If you are interested into how radial gradients are drawn in SVG, you might want to have a look at the following file.

It shows a radial gradient, overlaid with the different features of the gradient (center, focal point and radius). It shows an animation of a circle used to compute the gradient, all points belonging to that circle, at the same instant, have the same color (see a formal definition here). In short, there are three interpolations going on: one determines the center of that construction circle, one the radius of that circle and one the color of circle stroke. If you dig in the file and uncomment the color animation, you should see that when the circle’s stroke color is animated, the stroke perfectly matches the gradient behind and is therefore not visible (inside the gradient circle).

I’ve put here another example of an edge case, when the focal point is located on the edge of the center defined by the gradient element.


MPEG-4 BIFS and MPEG-2 TS Seminar @ WorldDMB

I gave the following presentations during the Seminar on MPEG-4 BIFS and MPEG-2 TS for the WorldDMB Technical Committee. The first one explains the basics of MPEG-4 BIFS and the second one shows the latest developments for Digital Radio Services, the new BIFS tools and profiles and the modification for the proposed carriage of those services over MPEG-2 TS. As usual, if you have any comment please contact me. Continue reading MPEG-4 BIFS and MPEG-2 TS Seminar @ WorldDMB

B. Pellan’s PhD thesis “Multimedia Scene Scalability”

It is a great pleasure to announce that the Ph.D. thesis of Benoit Pellan, that I supervised, is finally published and it is written in English. So don’t hesitate to download, read and comment it.


In this dissertation, we propose to apply the concept of media scalability, as defined in hierarchical coding, to multimedia scenes which are the choreographers that organize several media into a visual and interactive presentation over time. As a consequence, an initial scene is progressively enhanced by successive transformations, that we call adaptation updates, in order to generate an appealing presentation which is compatible with the user’s context. Our approach, called Scalable MSTI, is built on three scalability axes that separate the Media and the Spatial, Temporal and Interactive properties of a multimedia scene. Each of these axes is composed of scalability layers that enclose adaptation updates. These scalability layers are organized according to an order relation based on the adaptation parameters selected by the editor to cope with envisioned user’s contexts. The presentation alternatives that are described in a scalable scene can be represented as a graph where an adaptation decision corresponds to the selection of a way along an adaptation path. Multimedia scene scalability has been applied to the digital radio domain by enabling the progressive playback of multimedia services on receivers. Additionally, the adaptation capabilities of scalable services would allow multimedia enhancements on wide-screen receivers or would avoid disabling the screen of multimedia car-radios while driving because of security regulations banning the display of animations.

Communicating and Migratable Interactive Multimedia Documents

I’m pleased to announce that the work we have been doing for quite some time already on Interactive Multimedia Documents, on Widgets, on Home Networking, on MPEG-U is published in the Multimedia Tools and Applications journal.

C. Concolato, J.-C. Dufourd, J. Le Feuvre, K. Park and J. Song, Communicating and migratable interactive multimedia documents, Multimedia Tools and Applications, May 2011 [PDF] [DOI 10.1007/s11042-011-0805-2].

If you have comment, please contact me, I’ll be happy to discuss with you.

MPEG-4 BIFS ExtendedCore2D profile

ISO/IEC 14496-11:2005/Amd.7:2010 is an amendment to the MPEG-4 BIFS standard which defines a new profile, called ExtendedCore2D. This amendment is intended to improve services such as T-DMB mobile television as deployed in South Korea or Digital Radio services as shown in Figure 1. The goal of this profile is to enable richer services with reduced bandwidth requirements. It is based on the existing Core2D profile, extends it with existing tools from the MPEG-4 BIFS standard not yet included in the Core2D profile, and with newly defined tools.

Figure 1 – Example of BIFS Digital Radio Service – Live and audio-synchronized screen
(courtesy of VizionR)

Among the extensions of the Core2D profile from existing BIFS technologies, the ExtendedCore2D allows defining services with rich 2D vector graphics primitives. In particular, authors can now use Bézier curves (with the Curve2D or XCurve2D nodes) or ellipses. Additionally, the profile supports tools to stroke vector graphics objects, for instance with the LineProperties or XLineProperties nodes; and to fill or stroke objects with gradients using the LinearGradient or RadialGradient nodes. Using these nodes will save bandwidth as some raster images can be replaced by more compact binary vector graphics representations. Finally, the visual quality of the new services can now remain intact when a scene designed for a smartphone screen is displayed on a larger tablet screen. An example of Digital Radio Service on tablet is shown in Figure 2.

Figure 2 – Example of BIFS Digital Radio Service – Usage of vector graphics
(courtesy of VizionR and Fun Radio)

New and richer services defined with the ExtendedCore2D profile also need more compact and more efficient tools for scene graph management including layout description. For better scene management, the new profile includes the PROTO tool, to help reduce scene complexity and improve the coding efficiency. In term of layout, the new profile adds the ability to position objects, including text and vector graphics, in paragraphs with the Layout node. It also adds the possibility to transform, reuse, view and animate parts of the layout efficiently to achieve compact and appealing animations with the TransformMatrix2D, CompositeTexture2D and Viewport nodes.

The BIFS amendment also defines several new tools to enrich services. Some of them target a reduction of the bandwidth required by BIFS services. In particular, the CacheTexture node enables the carriage of compressed images within the BIFS stream, removing the use and signaling of some elementary streams dedicated for raster image delivery. The bandwidth gain can be important when the service contains many images, as shown in Figure 3. Some new tools provide new features for service authors. The EnvironmentTest node enables the design of services that adapt to viewing conditions, e.g. to the screen size, to the presence of keypad or to the viewing in cars. The KeyNavigator node facilitates the design of the navigation within rich scenes. With the Storage node, services can be designed to be persistent across activations and deactivations, offering the user a restoration of its settings. Finally, in T-DMB environments, it may be interesting to reuse, within the BIFS service, data carried outside the BIFS streams, such as Electronic Program Guides. For this purpose, a new type of BIFS update, called ReplaceToExternalData, is defined.

Figure 3 – Example of BIFS Digital Radio Service – News and non-synchronized screen with multiple images (courtesy of VizionR)

Groupe Multimédia / Multimedia Group