“Biblioteca Digital Multimídia” (Digital Multimedia Library
(www.bibliotecamultimidia.org.br) is an ambitious project for
disseminating free ondemand
and real-time content (video, audio, text and images) using
simultaneously two different transmission media: public Internet and
digital satellite broadcasting. The project was implemented by the
Embratel Institute, a not-for-profit institution founded and maintained
by the Embratel telecommunications company, with support by funds from
the Ministry of Culture, the National Library Foundation and several
private companies such as Siemens Brazil and StarOne satellite
provider. Among several other excellence centers, the Edumed Institute
was chosen as a partner to generate contents (video broadcasting as
well as distance and on-line courses) specifically in the area of
health sciences, and was equipped with a small TV studio in its
premises. Content is generated via a Polycom FX Clarity
videoconferencing dedicated machine, which transmits via ISDN at 512
Kpbs at SVHS quality to the data hub and teleport of Embratel/StarOne
facilities located in Guaratiba, Rio de Janeiro. High-capacity (up to
2,000 simultaneous users) Internet video unicasting and IP satellite
multicasting servers stream the content according to a 24-hour program
grid. Low quality, compressed copies of all video streams are stored at
an on-demand high-capacity (2 Tb) server, available on public Internet.
A network of 80 VSAT remote receiving stations has been established,
mostly at public libraries across the country. The Edumed Institute
generated four series of programs with
short 20- to 30 min lectures and interviews featuring medical topics to
lay people, delivered by experts), in collaboration with several
universities of the Edumed
Consortium, such as the State University of Campinas: 1) Health
& Life On-Line, 2) Brain & Mind, 3) Health, Myths and
Truths and 4) Speak, Doctor! In order to provide an interactive
channel, we have developed a Virtual Auditorium consisting of a webpage
with two panels: one at the left, receiving the streaming video through
a Microsoft Windows Media Player 9, and one at the right, with access
to a text-based chatroom. In this way, participants watching the
broadcasting can send questions in real time to the lecturer or
speaker, who will respond. The resulting chat script is stored. In
addition, the Virtual Auditorium has a website which can be used to
make available PowerPoint slides, articles, recommended links, a
webforum, etc., related to the presentation, thus enriching the
experience. We have also used this system to deliver a number of
on-line courses with synchronous and asynchronous video lectures on
several subjects, such as the history of neurosciences,
functional neuroanatomy, occupational health, pediatric oncology, etc.
The combination has been proved to be a very cost-effective and
efficient way to deliver interactive digital TV either via satellite
broadcasting supplemented by a terrestrial Internet link, or via an
entirely Internet-based solution. Video
transmission bandwidths of 128 to 256 Kbps have been found to
be the minimum accepted quality. Common difficulties have been all in
the reception side of desktop users, mainly fluctuations in
transmission bitrate and quality, audio and video freezing and
audio/video dissociation, so that we presently recommend the
satellite/Internet duo.
Acknowledgements: This work was made possible through a grant of Metron Inc., through the Law of R&D in Informatics (Ministry of Science and Technology Special Secretary of Informatics), and grants by the Instituto Embratel 21 through the Law of Culture (Ministry of Culture), as well generous grants of equipment and connectivity from Siemens, StarOne, TES and Metron.
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