Recent Research Developments in Learning Technologies (2005)
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Development of a virtual classroom player for self-directed learning M. Sheng*, B. Celler, E. Ambikairajah and J. Epps School of Electrical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia This paper reports the development and application of virtual classroom player (VCPlayer), a multimedia educational technology tool for the recording, playback and review of educational sessions in both local and tele-teaching environments. The VCPlayer allows the combination of two media streams synchronously, one displaying the lecture/tutor and one showing the electronic content. VCPlayer-based lectures have been trialled within postgraduate courses at the School of Electrical Engineering. Evaluation has revealed that students show a strong preference for the high-quality, more realistic delivery mode of the VCPlayer over static PowerPoint presentations. Lecturers producing content for the VCPlayer observed that it was as easy to prepare as traditional methods (such as handwritten notes or PowerPoint slides), but found that the combined voice and handwritten annotation gave them substantially better opportunity to communicate complex concepts. Educational benefits revealed during the VCPlayer trial will be discussed in this paper, along with its implementation for various platforms. Keywords virtual classroom player; educational multimedia; self-directed learning
1. Introduction In recent years, the traditional ‘lecture only’ classroom environment has been enhanced by various educational software and Internet-based tools that open up new and different possibilities in the classroom environment [1-2]. These enhancements have been shown to promote faster learning in an environment where student expectations of mixed-mode teaching delivery methods are increasing. Presentation tools are also increasing in popularity. An interactive electronic whiteboard is an excellent tool for classroom teaching [3]. Teaching with Tablet PCs has recently attracted attention as a potential tool for educational use and a “Classroom Presenter” system has been developed [4, 5] for delivering computer science courses. Anderson et al.’s surveys of this system [4] indicate that students pay more attention and gain a better understanding of the course material. To meet the ever increasing demand for new interactive teaching technology, various hardware vendors have also produced impressive products such as Winnov’s CBOX. CBOX is a presentation appliance that enables presenters to easily create and publish impressive presentations, and a CBOX player component enables users to view a presentation as if they were there, providing them with virtually an identical experience [6]. This paper describes the methodology and technology used in developing a novel virtual classroom player (VCPlayer), a multimedia tool for the recording, playback and review of educational sessions in both local and tele-teaching environments. While media players such as Microsoft Windows’ Media Player and RealNetworks’ RealOne player only allow one video stream to be played at a time, the VCPlayer we have developed allows a combination of two media streams to be played back synchronously, one displaying the lecturer/tutor and other showing the electronic presentation content. The viewer can dynamically modify the graphic layout during playback. The presence of a lecturer view, overlaid and synchronized with the annotation, simulates a natural classroom learning environment that convincingly overcomes learner fatigue when reviewing and playing back educational content. This paper also describes methods for recording educational sessions for use with the VCPlayer, based on either electronic whiteboard or Tablet PC input. *
Corresponding author: e-mail:
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M. Sheng et al.: Development of a virtual classroom player for self-directed learning
2. VCPlayer Design 2.1 VCPlayer and the Java Media Framework (JMF) The VCPlayer was written in Java. Besides being an object-oriented programming language that is portable across various hardware and software platforms, Java provides an application programming interface (API) for incorporating time-based media into Java applications and applets, known as the Java Media Framework (JMF). The JMF specifies an event-driven architecture for the development of applications that support both video and audio [7]. While other free or commercial APIs or SDKs, such as Microsoft’s DirectX SDK or IC Imaging’s ActiveX Control, exist to facilitate programming video and audio playback and capture application, the JMF goes a step further enabling the programmer to easily synchronize multiple time-based media streams. Figure 1 shows a snapshot of a recorded lecture being played back in VCPlayer. The recording was executed in our School’s virtual classroom. There are two media streams here, with one for the whiteboard contents and the other for the lecturer. The media stream containing the whiteboard content was recorded without audio and the lecturer stream with audio. It is important that the two media streams are precisely synchronized during playback, and that there is no deviation in synchronization over the time of entire session. When the presentation of multiple media streams is synchronized, it is essential to take into account the start latency of each stream. Without this consideration, playback of the different streams might actually begin at different times. The JMF’s method for synchronizing multiple video streams is to associate multiple Player objects with the same time base. The JMF provides a mechanism that allows one Player (the managing Player) to assume control over any other Player. By interacting with the managing Player, instructions are automatically passed along to the managed Players as appropriate. The managing Player takes care of the state management and synchronization for all other Players. For example, Player 2 can assume control of Player1 by calling player2.addController(player1).
Fig. 1 Two media streams, comprising the electronic whiteboard contents and the lecturer view, are played back synchronously in VCPlayer
Start
Stop
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Fig. 2 VCPlayer’s multiple media stream GUI interface
2.2 Acquisition of media streams for the VCPlayer In the previous section, we discussed a technique for synchronously playback of multiple time-based media streams. This section focus on the acquisition of media stream files, i.e. the PC contents and the lecturer streams.
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To record the two media streams, all a lecturer needs is a TabletPC (or an electronic whiteboard ‘SmartBoard’ plus a PC), a good webcam and a high quality microphone. The computer content is recorded using the “HyperCam” screen recorder software, and the lecturer’s stream can be recorded using a video capture program written with the Microsoft DirectShow API. The HyperCam software capture status, i.e. start, stop and pause, can be controlled by sending Windows Messages to it from within the video capture program. Figure 2 shows the GUI interface for capturing multiple media streams. The click of the red circle button will commence the recording of both PC contents and the lecturer view simultaneously. The other three buttons are to stop, pause and resume the recording of the two media streams. 2.3
Playback of educational content using the VCPlayer
The aim of the VCPlayer is to let students experience the real classroom environment as if they were in it. To this end, the student should be able to easily view both the lecturer and whiteboard contents simultaneously as shown in Figure 3. Because the lecture view window is overlaid on top of the whiteboard contents, it may obscure the part of the whiteboard the lecturer is annotating. A student can dynamically change the position of lecturer view window during playback by clicking an icon on the toolbar located at the bottom of the VCPlayer window as shown in Figure 4. These buttons provide a visual interface for switching between different pre-configured display layouts for the media streams. The other possible display layouts include the split screen mode for whiteboard contents and lecturer view windows, whiteboard contents only or lecturer view only.
Fig. 3 Lecture view window on bottom right
Fig. 4 Lecturer view widow on top left
A convenient feature of the VCPlayer is that a student can begin playing back from any point in the lecture by positioning the slider on the VCPlayer control panel to the desired point in the media streams, thus making self-paced review and self-directed learning much easier. The whiteboard contents and lecturer view are always synchronized when the positioning slider is manually positioned.
3. Evaluation VCPlayer-based lecturers have been trialled as an additional resource within postgraduate courses at the School of Electrical Engineering, University of New South Wales. Evaluation has revealed that students
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M. Sheng et al.: Development of a virtual classroom player for self-directed learning
show a strong preference for the high-quality, more realistic delivery mode of the VCPlayer over static PowerPoint presentations. Unlike PowerPoint slides traditionally made available outside of class hours, we found that students re-visited the VCPlayer-based lectures multiple times during their self-directed study. Students remarked that they were more easily able to learn difficult theory, equipped with the flexibility to replay the lecturer’s natural commentary. The VCPlayer is particularly relevant and important in an Australian university context, which serves a large population of overseas students from non-English speaking backgrounds. The VCPlayer provides these students with the opportunity to review either the whole class or merely those portions of the class that they have found difficulty in understanding due to their limited English skills. Our evaluation also found that below-average students tend to use the VCPlayer more frequently. Lecturers producing content for the VCPlayer observed that it was as easy to prepare as traditional methods (such as handwritten notes or PowerPoint slides), but found that the combined voice and annotating gave them substantially better opportunity to effectively communicate complex concepts. Trials of VCPlayer-based recording have been conducted both live (in front of class), using an electronic whiteboard, and in an office, using a TabletPC and a camera. Our evaluation has show that both modes of recording allow for similarly improved student learning. Benefits provided by the VCPlayer include the ability to easily record and archive lectures, the facility to make lectures and tutorials available to students for self-paced learning, and the synchronization of lecturer presentation with content annotation. The presence of a lecturer view in particular, overlaid and synchronized with the annotation, simulates a natural classroom learning environment, which greatly decreases learner fatigue when reviewing and playing back educational content.
4. Conclusion We have developed a media player that can synchronously play back two media streams, with one for whiteboard content and one for the lecturer. Recording of the media stream files is made very easy due to the integration of the Hypercam screen recorder and the capture programs into a single interface. The VCPlayer is particularly valuable for foreign language students, providing them with opportunity to review whichever parts of the class they have difficulty understanding. It also aids slower students, who can revisit the class in their own time. Thus, the VCPlayer we have described herein opens up new avenues and modes for effective and efficient teaching and enhances student self-paced learning. Distance learning courses can also be distributed via VCPlayer, and this prospect is an opportunity for future research.
References [1] C. Abdallah et. al, “Interactive DSP Course Development Teaching Environment”, in Proc. IEEE Int. Conf on Acoust., Speech and Sig. Proc., pp. 2249-2252, 1997. [2] P. Faggion, J. An, E. Ambikairajah, “Online Java Signal Processing Education”, in Proc. ICICS, 2001. [3] E. Ambikairajah, J. Epps, M. Sheng and B.G. Celler, “Evaluation of a Virtual Teaching Laboratory for Signal Processing Education”, in Proc. IEEE Int. Conf on Acoust., Speech and Sig. Proc., vol. III pp. 757-760, 2003. [4] R. Anderson et al., “Experiences with a Tablet PC Based Lecture Presentation System in Computer Science Courses”, in Proc. SIGCSE (Norfolk, Virginia), March 2003. [5] E. Ambikairajah, J. Epps, M. Sheng and B.G. Celler, Experience with an Electronic Whiteboard Teaching Laboratory and TabletPC-Based Lecture Presentations, Proc. IEEE ICASSP (Philadelphia, PA), 2005. [6] Winnov, Cbox Online, http://www.cboxonline.com/. [7] Sun Microsystems, Java Media Framework API Guide, JMF 2.0 FCS November 19, 1999.
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