Global Serverless Videoconferencing over IP

Thomas C. Schmidt, Matthias Wählisch, Hans L. Cycon, Mark Palkow

{schmidt, mw, hcycon, mpalkow}@fhtw-berlin.deFH für Technik und Wirtschaft Berlin

Email still is the Killer Communication App. in Internet - Why ?

Email is Unique to Computer Networks

Email is reliable and mature

Email is easy and free

Email is accessible everywhere

Email has full infrastructure support

What about Videoconferencing over IP(VCoIP) ?

VCoIP is Unique to Computer Networks

VCoIP is reliable and mature

VCoIP is easy and free

VCoIP is accessible everywhere

VCoIP has full infrastructure support

Agenda

VCoIP communication paradigm

VCoIP - where < are we > going?

A distributed communication scheme User Location Group Conferencing

The daViCo conferencing System Properties, Implementations Wavelet Video Codec

Conclusions & Outlook

VCoIPCommunication Paradigm

Video Conferencing Services request for

Session Orientation (synchronous service)

Person Orientation

Coping with Mobile Users (globally)

Group Support

Support of Privacy

Where Are We ?

• Serious Conferencing Applications via ISDN

• ISDN-formed ITU-T Standard H.323– Heavy burdened Infrastructure with Scaling Deficiencies

– Addressing via Telephone Numbers

– Local Relaying except for Telephony or Meta Directories

• Session Initiation Protocol (SIP, RFC 2543)– Own SIP Infrastructure or vaguely locatable SIP-Servers

– Addressing <user>@<SIP-server>

• Proprietary Centralised Services (MS NetMeeting)

Are We Going?

Distribution of videoconferencing is retarded by following the track of H.323 and such:

– Inertia of infrastructure

– Costs

– Inadequate, clumsy solutions

– Insufficient support of communication requirements

We need a new ‘internet-like’ approach to

VCoIP

VCoIP Distribution Recipes

•Provide an easy, intuitive VCoIP solution

•Provide personal, effortless addressing

•Provide automatic user location

•Remain rigorously neutral to infrastructure

•Avoid costs

•Focus on distributed, decentralised services

•Stick to internet attitudes

A Distributed, Intuitive Conferencing Framework

o Identify users via Email Addresses- Well known

- Globally unique

- Suitable for automatic relaying

o Peer-to-Peer principle waives specific infrastructure

- Multipoint conferences via multicasting

o Distributed, hidden information services

o Pure software solution

User Session Location

• Directories in domains locale to users

• Map Email to current Host-IP

• Directory location via– DNS MX-Record

– Name convention usl.<mx-domain>

• Decentralised administration &

authentification

A User Location Scheme

LDAP Session Data

DN: mail=charly@brown.net, dc=application

Note: LDAP allows for authentification & encryption

Required Optional

VCoIPHostNumber VCoIPMcastGroup

VCoIPServicePort VCoIPAppID

VCoIPServiceProtocol VCoIPAppProtocol

VCoIPTimeStamp VCoIPMimeType

mail VCoIPPrivateipHostNumber

cn VCoIPPrivateipServicePort

VCoIPStatusFlag

NAT Obstructions

NAT Gateways firmly object any Videocommunication.

Traditional ALGs intrude fundamental infrastructure.

Approach:

• Position USL outside NAT range

• Restrain NAT-GW from dropping state information

• Extract IP-Address and Port from packet headers

• Publish extracted address information to USL

daViCo Videoconferencing Software

Pure Software solution including

• multicast/multipoint video communication

• highly efficient video codec PACC

• MPEG3 audio encoding

• buffer latencies about 100 ms

• application sharing

• implements peer-to-peer model & usl scheme

• designed for best effort transport & effortless

use

Wavelet Video Codec

Real-time video codec based on fast low

complexity wavelet transform

Transforms whole images without blocking

artefacts

CIF (352 x 288 pixels) at 25 fps performs in

real-time on a 500 MHz Pentium Machine

with data-rates below 200 kbit/s

More efficient than MPEG4 or H.263 coders

Wavelet Coder and Decoder

DW T Q PC

IDW T IQ IPC/IAC

AC

PACC: Principle of Partioning, Aggregation and Conditional Coding

Image

Image

Lossless Decorelation Lossy Quantizer Lossless entropy coderPACC

PACC Decomposition

Wavelet Transform

03.02.2001 Wavele tprojekt H.L.Cycon 6

Lena 512x512 (Ausschnitt)

Original JPEG 1:64 WLT 1:64

VCoIP in Praxis

Conclusions & Outlook

VCoIP solution based on a light-weight peer-

to-peer model.

Ready-to-use approach for user addressing &

look-up.

Future Development:

Future of PACC Codec part of ITU-T H264

/MPEG Advanced Video Codec (AVC)

Future directory location via DNS Service

Record