25-02-2013, 09:31 AM
Digital Jewellery – The technical part
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ABSTRACT
In this paper we describe the technical part of the Digital
Jewellery project at the Institute for Geoinformatics
Münster, Germany. This project takes place during
summer term 2007. The two main parts are a video player
containing a bluetooth scanner running on our iDisplays
and several digital jewellery created by Jayne Wallace and
Patrick Olivier at the Culture Lab Newcastle of the
University of Newcastle. This text focuses on the software
part, not the digital jewellery part.
INTRODUCTION
During the last years, large displays have been getting
cheaper and cheaper. So more and more large displays are
placed into the environment. The Digital Jewellery project
tries to establish a more personal connection between
people and these displays. Normally, only impersonal
informations are shown on displays, like news, timetables
or commercials. But these displays could also be used for
showing some more of „you“. Our idea is to create some
digitial jewellery what will be recognized by displays and
show some personal information about you. In case you
think, personal information are only your name, your
address, your birthday, your mobile phone number, etc.,
you're wrong! How about showing some holiday photos or
movie clips? Or movies from your work or hobbies? Or a
movie clip you've just taken on your way to work? Maybe
it would be cool to show to your friends or colleagues or
just any person walking by the displays with you. We try
to find out how you and the environment will react to this.
TEST PROCEDURE
Technical part
During the last projects using bluetooth in any way, the
open source java bluetooth implementation BlueCove has
proved its vantages. The major disadvantage of BlueCove,
the missing Linux implementation and the only usage of
the Microsoft bluetooth stack, can be left out of focus
because all of the iDisplay systems are running Windows
XP SP2. The used video clips from the participants are
located on (different) webservers so that the video player
is able to load them on demand and video clips can be
exchanged without the need of changing anything on the
iDisplays directly.
Bluetooth scanner
The iDisplays need to know if any of the participants
wearing the digital jewellery are in range. Face recognition
is no alternative because of privacy aspects and the
problem, that participants should be recognized “walking
by” without the need for standing directly in front of a
camera. A bluetooth scanner has been developed during
the “Location Based Services” seminar by the project
“Interaction with public displays”. The scanner source was
already used by different projects and has proved its
vantages, so it will be re-used also for this project here.
The bluetooth scanner works in a passive way without the
need of any software saved or running on the client
bluetooth devices. There is just no alternative to this
because the digital jewellery only contains a bluetooth
device without an operating system around it like a mobile
phone has.
Video player
The video player is the second major part of the software.
In general, Java and multimedia are two things that don't
consort very much. A proof for that is the Java Media
Framework (JMF). It's latest achievement is the mp3
support. And this achievement has been introduced in
November 2004! So there is a problem to deal with
because the JMF doesn't know anything about modern
video codecs like MPEG-4, DivX or XviD. There are
several further (open source) project based upon the old
JMF but nearly all of them are in a early beta or almost
alpha stadium and not adapted for this project.
One project however, looked very interesting because it
has its beginnings in 2004 and is based upon FFMpeg, a
wide spread open source codec library with support of
nearly all common used video and audio codecs. The name
of this project is FOBS. This project is still active and the
latest version of the software has been released in January
2007. Another great advantage is that FOBS places itself
between the old JMF and FFMpeg. So JMF can be used for
developing and all encoding is done by FFMpeg. No
installation of FFMpeg on the system is required, which
reduces the administration complexity on the iDisplay
systems.
Digital Jewellery
The digital jewellery will contain a small bluetooth device.
What exactly isn't know yet because the devices are still
under development. The requirements are that the device
will operate continuously, without any external input and
will be “visible”. In this combination, “visible” means that
it will be visible to the bluetooth scanner, like any
bluetooth mouse or headset. Higher bluetooth devices can
be set to an invisible mode that will hide them from the
bluetooth scanner.
IMPLEMENTATION
Bluetooth Scanner
The bluetooth scanner mainly is one single thread which
starts several threads for the scan events. During the
bluetooth scan, the main thread is sleeping and starts a new
scan just after the old one has finished. After, not during
the scan, a list of found bluetooth devices is generated. Not
only devices belonging to the digital jewellery are found,
also mobile phones or laptops with bluetooth are in the list.
A lookup for all digital jewellery devices is done by the
database and a list of these devices is generated. The list of
all found devices is compared with the list of all
participants. Only matching devices are taken and
committed to the video player.
Video Player
The first goal while developing the video player has been
the ability to play video clips independent of any used
compression codes, e.g. MPEG-4, DivX, XviD. This
problem has been solved completely by using FOBS. No
configuration has to be done except adding the jmf.jar
(from the Java Media Framework) and the fobs4jmf.jar
(from the FOBS project) to the build path of the project.
Additionally a system library file fobs4jmf.dll has to be
placed either into a Windows system directory or just into
the directory the project will finally run from. The second
possibility has been chosen because so all needed files are
stored in a single directory and not widespread over the
whole system. To tell the JMF to use FOBS is also very
easy; it's done by the jmf.properties file. It's also just
placed in the main directory of the project. Thats the whole
configuration! No external software has to be installed nor
any configuration files has to be edited. This is a very great
advantage because under this terms and conditions, the
whole software will straight run “out of the box” on the
iDisplay systems.
CONCLUSION
The evaluation conclusion of the whole project will be
presented in another paper after the evaluation has finished
in august 2007.
The bluetooth scanner and video player developed during
this project are able to play video clips independent from
any codecs based upon found bluetooth devices in full
screen mode on the iDisplay systems at the Institute for
Geoinformatics. During a short test period the software
runs 24h without any problems on the iDisplays.