MACROMEDIA | FLASH MEDIA SERVER 2-MANAGING FLASH MEDIA SERVER | Classroom on the Internet using RTMP

Classroom on the Internet using RTMP
Anucha Tungkasthan1, Phaisarn Sutheebanjard2, Wichian Premchaiswadi3
Graduate School in IT in Business , Siam University
235 Petkasem Rd., Phasicharoen, Bangkok 10160 Thailand
1
aimdala_ohm@hotmail.com, 2mr.phaisarn@gmail.com, 3wichian@siam.edu
Abstract
Currently, e-learning web sites are used by student individually. Teachers prepare some
learning materials including exercises or homework and post them on the web pages.
Students will interact directly with the learning materials through completing a sequence of
programmed exercises. There are many e-learning web sites that are provided with excellent
contents and designs but they generally lack of interactive response and face-to-face
communication. Students cannot ask questions and get response immediately. It is just like
one way communication for learning. Therefore, it yields student’s boring and quit before
finish the course. Many students find that their learning is most effective when they actively
construct knowledge during group social interaction and collaboration. In this paper, we
propose inspire creativity of e-learning called Classroom on the Internet by using RTMP
[4]. RTMP (Real-Time Messaging Protocol) is a sophisticated TCP-based real-time
networking protocol which supports the efficient exchange of messages, synchronized data,
audio, and video. Teacher and students can publish streaming audio, video and other data
messages to present streaming media with interaction or navigation. We apply this protocol
with remote SharedObjects [4] technique which allows multiple connected users to share
data and user interfaces in real time, coupled with client and server data storage capabilities.
Using this classroom on the internet, students can immediately interact with teachers as
though they are studying in real classroom. We believe that it will be interesting place for
teachers and students to join and become the most important feature of e-learning web sites
that makes more attractive and complete e-learning system. In the future, it will further be
implemented as virtual school or university on the internet.
1. Introduction
Technologies such as streaming video, virtual learning environments and teleported
experiments are entering the Web-based learning arena. Along with the development of a
second-generation online education infrastructure, it will be necessary to consider changing
the interface of education such as reinventing pedagogy for the new interface, including
multimedia and hypermedia enhancements, and creating the educational standards necessary
for generalized deployment. Instructional learning goals should drive media selection,
application, and the course development process. Characteristics of the distance learner and
the impact of technology are also important considerations in instructional media selection
and course development. The new streaming technologies have made it easier than ever for
people to receive a quality education by bringing the classroom to the student. Imagine, a
teacher at one university campus delivering a lecture while students in a classroom two
cities away watch the same lecture in real time. In a residence hall not far away, a student
recovering from an operation watches a lecture recorded from an earlier class she had
missed delivered on-demand right in the comfort of her own room. In a city 5,000
kilometers away, a student is using the on-demand lectures to take part in the same course
delivered completely online. With the advent of streaming technology and the possibilities it
creates, scenarios like these have been repeated all over the world.
2. Related Work
Traditional study such as blackboard is provided a rich interactive between lecturer and
learner that cannot easily be replaced with PowerPoint slideshows. ChalkTalk [1] is
presented in this year. This system automatically produces e-learning materials from a
videotaped chalk talk lecture in front of an ordinary blackboard or whiteboard. But this lack
offs the activity. The Learning Activity Management System (LAMS) [2] is provided more
student interactive such as question and answer (with student answers shared with the
group), asynchronous discussion forum, synchronous chat. The pilot evaluation of LAMS,
only 15% of students were willing to discuss ideas in front of their peers in the classroom,
but over 80% of the same students were willing to discuss their ideas within LAMS. elearning is provided self-managed learning that learner should to study when they want, but
some group of people still like traditional teaching, where the lecture times were fixed [3].
Therefore, we proposed the additionally feature for e-learning to make virtual classroom
were consisted the learner and the lecturer on the internet. This virtual classroom we fix the
times to learn but the learner and lecturer can access to the classroom from anywhere that
have internet. We proposed two features for the virtual classroom. Firstly, the lecturer
teaches by PowerPoint slide. So the learner can should synchronous the slide page with the
lecturer or the learner should the slide page by them self that can difference from the
lecturer but not over the page that lecturer go to. This feature makes the learner comfortable
to learn. Secondly, in a virtual classroom the learner and lecture can have activity with share
board. This is the two-way communication that will make more interactive. Nowadays,
there are many collaboration and communication programs in the market such as
NetMeeting, CollabWorx Virtual Classroom, Breeze, MSN, or Skype. Some programs are
free and some are not. Each program has pros and cons. Let’s us consider the features
offering in each program.
3. Design of Classroom on the Internet
3.1 Functions and protocol classification
There are some requirements that should be taken into consideration as follows: 1) shared
object component and 2) VDO streaming part. There are many objects such as white board,
presentation, chat, AV presence and people list in classroom on the internet. They are
allowed to be shared with other students. Remote shared objects are managed by streaming
server. Client can access shared objects and get update whenever a change is made to that
shared object. VDO streaming part is also provided on the streaming server. The Top level
design is shown in Fig. 1.
Figure 1 Top level design and classification function of Classroom on the Internet
3.2 Client/Server sequential process
There are four steps in sequential process in order to obtain streaming objects. Firstly,
client requests for the HTML and SWF files by using HTTP on TCP connection. Secondly,
web server send HTML with embedded links and SWF files back to the client according to
their request. Thirdly, client sends message to flash media server by using RTMP protocol.
Lastly, shared SLV file and streaming media are sent back to client. The general connecting
and displaying share and streaming media is shown in Fig. 2.
Figure 2 Sequence procedural in general connecting and displaying share and
streaming media
3.3 Collaborative functions for teacher and student
3.3.1 Login function
When student or teacher wants to enter in the classroom, they must login with correct
username and password. In the classroom, they are allowed to use shared objects or
resources.
3.3.2 Whiteboard function
The purpose of using this function is to provide a collaborative environment for students
and teachers. They can write message in text format and draw line on shared whiteboard
environment in real time. When they want a message or line, they must select tools by
dragging and dropping them on the whiteboard. They can also delete objects by pressing
delete key on the keyboard. Students can write or erase any items at any time they want.
They are equally authorized in this classroom.
3.3.3 Presentation function
This function allows creating a presentation in SWF format. This function contains two
modes. The first mode is teacher mode. Teacher can fully control the presentation. Students
can see the same frame simultaneously. The second mode is student mode. Student can
navigate the presentation by using next and back buttons in order to view the presentation.
They are not allowed controlling the presentation that the teacher has corresponded. The
presentation function requires SWF presentation file.
3.3.4 Chat function
This function supports teacher and students for chatting in regular text format. They can
send message to other people in the same classroom. Text can be selected in different styles.
3.3.5 List of students
This function displays teacher and students name that login the classroom. All usernames
appear on the list in the classroom that is used to identify who they are.
3.3.6 Audio/Video presentation function
This is very important function for face to face communication. VDO camera and
microphone are essentially needed for this function. Teacher and his/her students can send
and receive audio and video within the same classroom. If someone is sending audio or
video or both, the other people can see and hear as well.
4. Supporting technology
4.1 Flash Media Server architecture overview
The Macromedia Flash Media Server (FMS) platform consists of two parts: the server,
which provides the means of communication, and Macromedia Flash Player. Applications
consist of a client Macromedia Flash Movie (SWF file) that is run by Flash Player. Server
components are share with all clients. The server component consists, minimally, of an
application folder that we have created on the server side running Flash Media Server. This
folder can optionally contain Server-Side Communication ActionScript (ASC) files and
other resource files used by the communication application. The server and the Flash client
application communicate over a persistent connection using Real-Time Message Protocol
(RTMP). In a typical scenario, the Flash client is delivered to Flash Player by a web server
over HTTP. The Flash client then establishes a persistent connection to Flash
Communication Server using RTMP, allowing for an uninterrupted data stream to flow
between client and server [4]. The RTMP protocol of communication for Streaming media
is shown in Fig. 3.
Figure 3 flash media server provides a RTMP protocol of communication for
Streaming media for client.
4.2 RTMP
Real-Time Messaging Protocol (RTMP) is a protocol for client-server communication. It
is a proprietary protocol developed by Adobe Systems (formerly developed by Macromedia)
that is primarily used with Macromedia Flash Media Server to stream audio and video over
the internet to the Flash Player client, but can also be used for general remote procedure
calls (RPC). RTMP is basically a TCP/IP protocol designed for high-performance
transmission of audio, video, and data messages [4].
4.3 Client-Sever connection Flow
When the client connects to the server, the server calls application start method to run.
Next, the server-side will make and hold connection. The logic in this method determines
whether to accept or reject the connection. Back on the client side, the on status handler is
called to report whether the connection was accepted or rejected. When the client closes the
connection, the server-side disconnects and closes session [4]. The connection flow
between clients with server is shown in Fig. 4.
Figure 4 Connection flow between client with server via RTMP protocol
4.4 Shared objects
Remote shared objects are managed by Flash Media Server and provided messaging, data
synchronization, and data storage services. Flash clients connect or subscribe to a remote
shared object and receive updates whenever a change is made to that shared object. Also,
messages can be sent to all clients connected to a remote shared object. A remote shared
object can persist across application sessions, or be temporary [4]. The shared object objects
provide data storage and synchronization services for clients are shown in fig. 5.
Figure 5 Shared objects provide data storage and synchronization services for
clients.
5. The Implementation
We test Classroom on the Internet on Local Area Network (LAN). The client site must
contain flash player application in order to display flash movie. Flash media server and IIS
must be installed in streaming/web server. The experiment is set up and run on windows
platform.
5.1 Login function capture
Figure 7 Show a page of Login function
5.2 Presentation function capture
Figure 8 Show a page of presentation function
5.3 Whiteboard function capture
Figure 9 Show a page of whiteboard function
6. Conclusion
The classroom on the internet can work well according to the defined functions.
The classroom on the internet can work as any classroom in the school. With the use
of computers and information technologies, the barriers of space and time can be
broken down.
This classroom is an opportunity for many students in rural area
that their homes are far away from school. They will have a chance to study and
communicate with teacher and other students. Using this classroom on the internet,
we do not imply that it is better than the real classroom in the school but it is a
choice in order to move school closer to students who lack of the opportunity. We
want classroom on the internet to be one standard feature from several features for elearning. We believe that it will be an important feature for electronic learning
system in the near future.
Reference
1
2
Satoshi Ichimura, “Delivering Chalk Talks on the Internet,” International
Conference on System Sciences, IEEE 2007.
James Dalziel, “Implementing Learning Design: The Learning Activity
Management System (LAMS),” ASCILITE, 2003, pp593-596
3
4
5
M.Smith, “Use of Web-based curriculum and assessment in the teaching of
Information Systems subjects,” ITICA, 2002
Adobe Systems Incorporated, “LiveDocs (online Documentation),” Macromedia
Flash Media Server Documentation, Adobe System Incorporated 2007
http://www.adobe.com/support/documentation/en/flashmediaserver/
Kristopher Schultz, “Taking Control of Connects,” Flash Communication Server
Article, Developer Center 2007
www.adobe.com/devnet/flashcom/articles/connections.html
6 Giacomo Guilizzoni, “Creating Your First Broadcast with Flash
Communication Server MX,” Flash Communication Server Article,
Developer center 2007
http://www.adobe.com/devnet/flashcom/articles/broadcast.html
7 Srinivas Manapragada, Giacomo Guilizzoni, “Understanding the Component
Framework,” Flash Communication Server Article, Developer Center 2007
www.adobe.com/devnet/flashcom/articles/framework.html
Download PDF