Tools and applications used in the context of netzspannung.org
In the context of netzspannung.org, streaming technology is primarily employed for building up a video archive and for making this available online, where it can be freely accessed and used. Since 2001 selected series of events and lectures have been recorded and archived. Offering high-quality streaming presupposes professional video and sound recording as well as encoding, keywording, inputting metadata and archiving. The section "Positions" provides extensive material in several streaming formats, comprising lectures recorded at a variety of events. At netzspannung.org streaming media are also used in the field of "Learning".
[link 01] Positions |
[link 02] Hypermedia Tele-Lecture (German)
[link 03] Learning
The term streaming means the packet-oriented network transmission of sequentially organized, multimedia content over the Internet and its immediate presentation on the display the user. The conventional form of data transfer is the download, where a file is copied completely onto the receiver's computer. The file can only be used after it has been completely transmitted. However, the complete download is inefficient for transmitting time-based media and the large volumes of data involve lengthy waiting times.
By contrast, streaming media technology allows video and audio files to be played while transmission is still in progress. A data stream can be directly played with a slight delay without having to download and store the file. The data packets are sent to the receiver in a continuous data stream, where they are reproduced in "relatively" real time.
For a streaming transmission, regardless of whether it is a live webcast, on-demand or near-on-demand, the video/audio signal (analogue or digital) is first converted into a compressed (encoded) digital signal suitable for streaming and then transmitted by a special server (streaming server). In the case of a webcast, the encoded data stream is not normally stored as a file, but is distributed directly by the server in the unicast or multicast process. Unicast is more frequently used because multicast packets are often not allowed through by firewalls on account of their security settings. On the receiver side, a player is required, i.e. a programme that receives the data packets, decodes them, and presents them on the display.
Links to the theme streaming:
[link 04] http://www.realnetworks.com/
[link 05] http://developer.apple.com/darwin/projects/streaming/
[link 06] http://www.videolan.org/
Streaming as a publishing possibility
Hitherto discourse on media theory has mainly been mediated on a textual basis. Although publishing texts online does away with printing costs, nevertheless it remains labour-intensive and costly. As a result, even important lectures and workshops often cannot be published at all or only to a limited extent, meaning that they are only accessible to the small circle of people who were actually present at these events.
Here streaming technology opens up a new cost-advantageous publication method. Recorded streams can, in addition, be archived and permanently published on a website. Since 2001 the netzspannung.org team has been taking advantage of this opportunity to make available a video archive with topical scientific lectures, thus reaching a wider audience.
[link 07] Lectures
The mobile unit
Recording, streaming and archiving are complex work processes, in effect requiring an entire production team, with people operating camera, lighting, sound and video equipment, rather like a small television crew. With a view to making scientific lectures accessible to general discourse at a relatively low cost, a mobile multimedia production and publishing environment has been developed, the "mobile unit".
The mobile unit is a transportable webcast studio for producing and publishing time-based media on the Internet. Its compact modular construction contains a complete web video-editing facility. Up to four video sources can be connected, mixed and edited. The network module for different bandwidths, the multimedia editing module, and the media-publishing and delivery module provide an advanced production environment. The mobile unit allows video encoding and streaming in all the relevant formats (Quicktime, RealMedia, Windows Media, MPEG-1, MPEG-2) and resolutions. It accesses the netzspannung.org media server via a preset Internet connection. Independent of physical networks, the mobile unit can set up a wireless-linked, server-supported production environment, providing it with multimedia services.
The design concept of the mobile unit ensures flexibility through modular construction. All its components have been developed in transport pack design, permitting fast, cable-free, plug-and-play operation.
Easy streaming - a new streaming concept from netzspannung.org
In the last few years streaming technology, especially the hardware, has been developed to such an extent that today almost every PC user can use this technology. Currently, however, there are no products available on the software market that enable simple implementation of streaming events. The problem lies with the streaming server, but also with the interfaces, which offer a - for the inexperienced user - very complicated graphical user interface with many different streaming profiles, thus requiring specialist knowledge.
The concept of "easy streaming" creates a radically simple client/server solution for the streaming event. Server side configuration and selection of the streaming profile are kept as simple as possible. The streaming process is controlled by just two functions - START and STOP. Easy streaming increases the possibility of using the mobile unit as a production tool because the streaming process can now be controlled in plug-and-play mode even by users with no expert knowledge.
PFUHL, Daniel, PERANOVIC, Predrag: Mobile Streaming Lab - leading to a modular learning environment. In: Proceedings of the eight international conference on virtual systems and multimedia - Creative digital culture, VSMM 2002, Gyeongju, Korea, 25th-27th September 2002, Seoul, Korea: Kiwissoft, pp. 578-584.
[link 08] Download [PDF | 470 KB]
The hypermedia tele-lecture
In collaboration with Prof. Dieter Daniels, the netzspannung.org team has produced an interactive tele-lecture designed to show how streaming technology can be used for educational offerings on the Internet. The hypermedia tele-lecture offers the recipient synchronously, with the lecture, additional information on individual passages. Thus, while the lecture is playing, links to websites and media files appear, which can be shown as part of the presentation.
In order to link the different media semantically, to present them, and to interrelate them temporally and on an event basis, SMIL (Synchronized Multimedia Integration Language) was used. SMIL enables different media contents to be easily synchronized in time.
[link 09] About SMIL
[link 10] Hypermedia Tele-Lecture (German)
Prototype experimental streaming applications
Interactive conference format
Participants invited to the "Memoria Futura" symposium, organized in 1999 by MARS, included not just speakers on the location but also experts who took part in the symposium via the Internet, making contributions of their own. In the process a combination of streaming and ad-hoc text-based input of content was realized. The live streaming enabled the experts present online to follow the speakers on the location and to send comments via a specially designed text-input interface. These texts were selected by a moderator and visually presented to both the audience and the speakers. This means that during the symposium an interactive communication and information system was tested out that bundles textual and visual information and also supports two-way communication.
[link 11] MARS Projekt: I2TV - interaktive Konferenz (German)
Broadband streaming in teaching
In Summer Semester 2002, during a co-production with the Burda Academy, the lectures of the "Iconic Turn" series of events were transmitted as high-resolution audio and video streams (MPEG-1 and RealMedia) via the lines of the German Research Network into the lecture theatres of the universities and colleges involved, where they were projected onto large screens. This streaming model does not address the individual user in isolation but expands and supplements the traditional lecture by creating an "electronically enlarged lecture theatre". The telematic reception takes place in a public room, which, in contrast to the individual reception on a home computer, enables the listeners and those leading the discussions to exchange ideas or a tutor to comment on the proceedings.
Especially in view of the scarce funds and tight budgets currently affecting institutions of higher education, streaming technology shows potential here for improving education and training, and for networking fields of interest.