Download - Video Conferencing Technology

8/12/2019 Video Conferencing Technology

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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