Human Computer Interaction
ERCIM News No.46, July 2001 [contents]

Físchlár on a PDA: A Hand-Held User-Interface to Digital Video

by Hyowon Lee and Alan F. Smeaton

At the Centre for Digital Video Processing, Dublin City University, we are working on diverse access to Físchlár, a web-based digital video processing and management system that allows its 1,000 users within the campus to record, browse and playback broadcast TV programmes for learning and for entertainment purposes. Since late 2000, we have been developing and testing innovative video content browsing interfaces for mobile devices such as PDA (Personal Digital Assistant), to provide our users with mobile access to Físchlár.

As on-going research in digital video management, we have developed an experimental video system called Físchlár which allows a user to initiate the recording of TV programmes from one of 8 major TV channels in Ireland. The requested programme, when broadcast, is recorded in MPEG-1 format and is analysed for automatic indexing with camera shot/scene detection, and extraction of representative keyframes to be used at a user’ content browsing interface through a web browser. Clicking on a displayed keyframe on the screen starts streaming the video from the clicked moment onwards, thus allowing the user to watch the recorded content. The system has been deployed since July 1999 in the University’s computer labs and residence through a LAN to students and staff, and currently more than 1,000 users have registered and have been using the system to record and browse TV programmes in their own time. This allowed us a campus-wide user study of internet-based video browsing and usage behaviour.

Applications of Físchlár System
Using the system as an experimental testbed, we have been exploring various aspects of video services and possible applications including Físchlár-PTV, a personalised recommender system which uses case-based reasoning and a population of users to recommend TV programmes which users are likely to want to watch. Also under development is work to allow our current users to access the system through wireless LAN using PDAs and mobile phones. A design framework has been developed to help us design various video browsing user-interfaces to support users’ differing needs and preferences; we used this framework to develop several distinctive keyframe browsing interfaces currently used in the Físchlár system which are suitable for desktop PCs with relatively large monitors and the use of a mouse.

Design Framework for Video Browsing Interface
The purpose of this design framework is to allow us to design and provide many alternative browsing interfaces to different users for different tasks. This framework enumerates possible design options for different categories. In summary they are:

From this framework, ‘designing a browsing interface’ is to simply select a possible option from each category. For example, selecting Single layer / Relative time / Temporal presentation specifies one distinctive browsing interface, currently available on Físchlár’s desktop browser as one of the browser options. This method allows us to come up with various interfaces that were not thought of before, for the same underlying Físchlár system.

Video Browsing Interface on a PDA through Wireless LAN
Along with desktop-based video browsers currently deployed to our user population, we are developing mobile applications to allow our users to access the system through a wireless LAN within the campus. While working on technical development to allow keyframes and streamed video data from Físchlár to communicate with mobile devices, we are designing and building suitable browsing interfaces for such devices. We use the design framework to make suitable decisions for small-screen, button-operated PDA platforms (Psion Revo and Compaq iPAQ), and one of the example designs shown in Figure 1. In this design, we also take into account the particular usage environment of a PDA: using the device on a busy street, in a shaking bus, holding it with 1 or 2 hands. Interfaces for mobile devices should be designed in such a way that the frequency of user interaction could be high but the range of interaction choices should be limited. The design in the Figure features only 4 main buttons to navigate through and within layers with a thumb while holding the device with the same hand. With this kind of design, the interaction becomes similar to that of video game consoles, a style that requires less intensive and constant visual attention at any given moment, careless tapping is acceptable with simple, easily reversible actions. As our wireless LAN becomes more used on campus, our students and staff will use this interface to access available programmes from Físchlár with their own PDAs.

Browsing interface for small-screen, button-operated PDA platforms.

While working on more useful video indexing techniques such as more precise shot/scene detection, object identification and tracking, and teletext-based searching and alerting, we are also considering mobile phone access to Físchlár, heading more towards ubiquitous access to video information.


Please contact:
Hyowon Lee and Alan F. Smeaton — Dublin City University, Ireland
Tel: +353 1 700 5262
E-mail: {hlee, asmeaton}