OVERCOMING TECHNICAL FRUSTATIONS IN DISTANCE EDUCATION TELE-(4)

Modern information technologies are transforming the way people learn. E-learning provides new possibilities for personalized learning at home or in the workplace, reduces the need for costly classroom training, and enables an optimal balance between tradi

2.3 tele-TASK Content CreationBased on the above considerations, we thought about electronic content creation with the needs of online lecturing and the reduction of the traditional costs in mind. Our basic idea is, to use the original lecture to produce e-learning content on the fly. But the most important requirement was the easy use for operators and end-users. The complete classroom situation including the desktop of the presenters computer, the video and the audio should be mapped into electronic course material. We desire to transfer the complete course live and on-demand to the internet. Also for offline usage, the course data should be saved. Figure 1 shows the structure of the tele-task system.Figure 1: Structure of tele-TASK In the following we show the different parts of the system.2.3.1 Transmission of the desktopVarious online lecturing systems (see Real [11], Microsoft [12], AOF [10], ...) have to run on the presenter’s computer. In these cases special requirement are claimed to the presenter’s computer. Often, those solutions call for special operation systems, special presentation software or high CPU power. In the case of non computer science lectures this presents a big problem. Most lecturers are unwilling to install anything new on their computer, or they do not have permission to do so. The solution is to deliver the desktop to another computer. This transmission is done with VNC [13]. VNC allows to transfer a desktop, no matter which operation system, to another computer without the loss of quality. To reduce the bandwidth we are using tightVNC [14] which transfers less packets than original VNC and it also compresses the packets. On the encoding machine, the desktop is processed further more.2.3.2 Capturing Video and Audiotele-TASK supports two different ways of accessing videos. The first solution is to use a video device connected directly to the encoding machine. By using the Microsoft DirectX library [15], we can access any video device connected to the encoding machine. This could be e.g. a cheap webcam, an analog video camcorder or firewire videocamera. The system supports multiple video devices which could be switched during the recording. Video resolution can be set up for each device seperately. Audio can be delivered via Firewire over the videocamera to the encoding machine, or by the anolog or digital audio input. The second way of transfering the video is to send it over the network. tele-TASK provides a tool for transmitting and receiving video and audio over the network. In those cases, the encoding machine can be set up in different locations.2.3.3 Synchronisation of the streamsThe encoder consumes altogether three streams (video, audio and desktop). The developed tele-TASK software package combines the three input streams. Figure 2 shows an example for the arrangement of 4 Streams (Video, Audio, Desktop and Table of Content). The arrow shows the coherence between the video