video conferencing technology
TRANSCRIPT
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Video Conferencing
Technology
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Outline
Goal
Existing Tools and Problems
VCT Features
Technology Used
High-level Design
Implementation
Testing
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Existing Tools
iChat is a video chat application from Apple. Mac Os hasbuilt-in iChat pluggin. Windows users can use iChat byinstalling AOL instant messenger
oVoo is a video conferencing tool. Download and install
oVoo software. Currently supports only Windowsplatform.
Stickam is a social networking site that allows users topost their live videos,pictures,start video conferencing.
Adobe acrobat connect pro is a web conferencing toolfrom Adobe. It allows remote desktop sharing, slidesharing, web conferencing.
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Problem with existing tools
Requires users to download and install
additional software
Platform dependent
Complex user interface
High cost
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Features of VCT
No need of additional software download
and installation
Browser based video conferencing
Platform independent
Simple user interface
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Features of VCT
Create new public or
private chat rooms
See list of chat rooms
with users countPrivate chat room
requires users to
enter password
Private chat room list
Enter password
Create chat room
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Features of VCT
Live video chat withfriends
See list of attendees
in chat room Invite your friends to
the chat room bysending an email
Friends can join yourchat room withoutcreating a VCT userid
Send email
Chat room page
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Features of VCT
See list of users who
has VCT account
View users online or
offline status
List of users with online offline status
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Features of VCT
Users can record
video message and
send the link to
friends
Record video message
Send email
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Features of VCT
Users can play video
message by clicking
the link in email
Play video message
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Technology Used
XHTML is a markup language used to create front-end of the web page.
PHP is a server side scripting language used to create dynamic web pages Authenticates VCT users in login
Creates new VCT user account in signup
Allows Flex applications to access MySQL database
MySQL is the back-end database used to store VCT user accounts
Adobe Flex is used to create client-side applications that interact with FlashMedia Server (FMS) Flex is combination of MXML and ActionScript
MXML used to create the layout of user interface of the application
ActionScript used to create interactivity to user Interface
Flex applications are compiled into SWF and embedded into XHTML
Apache HTTP Server is used in VCT to host XHTML ,SWF files, PHPscripts
Adobe Flash Media Server
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Adobe Flash Media Server
VCT uses Adobe Flash Media Server as theback-end server for real-time video conferencing
Adobe Flash Media Server is a streaming media
server that supports one-way and multi-waystreaming applications
VCT also uses FMS for recording and playingvideo messages
Adobe Flash Media Development Server thatsupports multi-way streaming is freely availablein the Adobe web site
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VCT High Level Page Flow Diagram
Login Signup
Dash
board
Create
chat
room
Video
Message
Find
users
Public
chat
room
Private
Chat
room
Password
New User
back
On successful authentication
Joinpublic room
Joinprivate
room
VCT page flow diagram
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Web Browser Apache Web Server
http://localhost/Login.php
MySQL
database
Execute
scripts
PHP script
HTML
output
from PHP
query
result
GET
Login.php
POST
LoginSubmit.php
VCT Login implementation
LoginSubmit.php script authenticates the user and if login
succeeds, it loads Dashboad.php
Dashboard webpage has SWF embedded in it
VCT login implementation diagram
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Web Browser Apache Web Server
http://localhost/Signup.php
MySQL
database
Executes
scripts
PHP script
HTML output
from PHP
execute
scripts
query
result
GET
Signup.php
VCT Sign-up implementation
POST
SignupSubmit.php
Sign-up allows VCT users to create new records in the MySQL database
VCT sign-up implementation diagram
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VCT Dashboard Implementation
Web ServerWeb browser
HTTPRTMP
Flash Media Server
swf
Dashboard webpage has SWF embedded in it
Web Server sends SWF over HTTP to the web browser
Flash player plays SWF and makes connection to FMS
VCT dashboard page implementation diagram
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VCT instances
Dashboard initially connect to
master instance of FMS
application
When users joins chat room
connection to individual roominstance is made
Users in each chat room are
completely unaware of users in
the other chat roomsInstances allows different
group of people to access same
application without interacting
with other groupVCT active instances in FMS console
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VCT shared objects
VCT uses remote shared objects for storing chat
room names and users list
Remote shared objects are managed and stored
by the server and are used for storing,messaging, and synchronizing data
Updates made to the remote shared object are
received in real time to all connected clients
Remote shared objects can be either persistent
or non persistent
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VCT shared objects
Applications Folder
Application Name Folder
sharedobjects Folder
_definst_
instanceName
Sharedobjectname.fso file
Sharedobjectname.fso file
VCT shared object storage structure
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VCT shared objects
VCT uses shared
objects for storing
chat room names
chat room users list
private room
password
VCT active shared objects in FMS console
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VCT streams
VCT transmits audio and video streamsbetween Flash client and FMS for videoconferencing
The FMS server allows users to publish orplay streams.
User publishes live webcam streams to
FMS server and other users subscribes tothe published stream
Stream names should be unique
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VCT streams
VCT active streams in FMS console
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VCT Find Users
PHP MySQLFlex
Flash Player Web Server
Sends user data request
PHP sends back data
query
Gets result
Flex application sends user data request to back-end PHP script
PHP scripts execute the request and queries MySQL databaseMySQL sends result to PHP which then processes the result
PHP scripts sends data back to Flex in XML format
VCT find users implementation
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VCT Video Messaging
Applications Folder
Application Name Folder
Streams Folder
_definst_
instanceName
Stream name .flv file
Stream name .flv file
Streams published for recording are stored in FMS application
as Flash Video files (flv)
VCT uses stored flv file for playing video message
Video message storage structure
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Usability Testing
VCT is tested among different age groups In the age group of 4-15, I need to guide them to
use VCT. But once I walked through steps, theygot easily adapted with the tool
In the age group of 16-50, they learned the toolfast. They suggested some enhancements to thetool like richer user interface, enhancedauthentication etc.
In the age group of 51- 65, they found it difficultto create new user accounts and login to website. They liked the method of joining a chatroom without logging in
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Usability Testing
Graph shows usability
rating versus age
Usability rating peaks
between the age of35-40
Usability testing graph
Usability
0
2
4
6
8
10
0 10 20 30 40 50 60 70 80
Age
UsabilityRating
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Performance Testing
Server bandwidth (BW)=(P*N)*S, P is number of
publishers, N is number of subscribers and S is streams
encoded at constant kbps
Total Server Bandwidth
0
1000
2000
3000
4000
5000
6000
7000
1 2 3 4
Number of Users
ServerBandw
idth(KBits/s)
Bandwidth graph