Internet TV – Yet another TV ??Internet TV – Yet another TV ??

Adrian Hornsby

Broadcast Multimedia course – TUT - 2008

Short on Internet

Internet − world's largest computer network− collection of smaller networks, computers, and

people who use them. − around 28 million people

Until recently, multimedia and internet were not really going together

− Not enough bandwidth, load, errors, traffic ...

Yet another one ...

Digital Media Revolution …• Huge increase in media content• Faster communications Faster communications • New user experience• New consumer demand

10/29/08

New digital devices + new digital transmission systems =

New digital transmission system

Yet another TV system !!!

Internet Television (TV), iTV− Television like content distributed through the

internet. Running on existing IP infrastructure (DSL, Wifi, 3G data ...)

Distribution model− Live Streaming− VOD− But also P2P (P2PTV)

Tell me more ...

Differ from IPTV− Not a dedicated network but over the internet

No real QoS− Does not require set-top box− Provider not always clear

Legal and none legal content − Quick to market with Low investment cost− Usually uses advertisement as main revenue

And how does that one works ??

Browser + media player (plugins)− No special equipment, just a computer and a

connection to internet Several options ...

− HTTP streaming (basic and advanced flavor)− RTP based multicast streaming− RTSP based streaming

HTTP streaming ? hmm ...(basic flavor)

Simplest and cheapest way to stream video from a website

No special type of website or host − recognizes common video file types

Good option for websites with modest traffic No live video

− HTTP method needs complete files stored on the server.

− No automatic detection of end user's connection speed

different file for different speeds

HTTP streaming(basic flavor)

HTTP-like live streaming 1- Clients request with HTTP-Get message

2- Server replies with a HTTP-OK response

3- ... continuous stream of data (usually port 8000)

4- Also referred as HTTP-push long-lived HTTP connection. keep the connection open by running a long loop

HTTP streaming basic flavor

WebServer

Web Browser

Media Player

HTTP meta file

HTTP content

HTTP streaming (advanced flavor)

Similar to basic flavor except media sent by specialized streaming media server

− Data delivery process differs No passive http push technique Data send actively and intelligently,

− eg. data rate associated with compressed media streams Server and client in touch, responses to feedbacks Stream usually controlled by ZeroWindow / KeepAlive

mechanism − Receiving host use the window field in each acknowledgment to inform the sending host how

much more data it can receive [rfc793],0 if receiver is pausing the stream. When playing resumes, the receiver sends another ACK with a nonzero window size.

HTTP streaming (advanced flavor)

Web Browser

Media Player

HTTP meta file

StreamingServer

HTTP media content

WebServer

... hmm I prefer advanced flavor !

More efficient network throughput Better audio and video quality Support for advanced features Larger number of users Content copyright handling Multiple delivery options

HTTP streaming servers example

Basic flavor− Apache

Special flavor− Shoutcast− Icecast− VLC− Window media server

RTP-based streaming

So called multicast streaming − requires global multicast address (€€)−

Combining RTP over UDP More for Live events, no “real” control on

stream

subscription No subscription

RTPheader

Real-Time Transport Protocol (RTP)(optional)

RTPheader Compressed video

RTPheader Compressed sound

Sender/Receiver report

UDPIP RTP

RTP Profile

RTP packet (V)

RTP packet (A)

RTCP packet (C) (option)

UDPIP RTPUDPheader

UDP packet RTP Profile

How does my device access the media stream ??

Listen SAP announcement (default 224.2.127.254:9875)

Access SDP (Service Description Protocol) v=0o=QTSS_Play_List 1460227057 502868560 IN IP4 130.230.50.48s=stream-32c=IN IP4 239.252.80.5/1b=AS:375t=0 0a=x-broadcastcontrol:RTSPm=video 5004 RTP/AVP 96b=AS:248a=rtpmap:96 MP4V-ES/90000a=control:trackID=1a=cliprect:0,0,240,320a=fmtp:96 profile-level-id=1;config=000001...a=mpeg4-esid:201m=audio 5006 RTP/AVP 97b=AS:127a=rtpmap:97 mpeg4-generic/44100/2a=control:trackID=2a=fmtp:97 profile-level-id=1;mode=AAC-hbr;...;a=mpeg4-esid:101

SDP1 SDP2 SDP3 SDP4 SDP5 SDP6 SDPn

RTP streaming

Web Browser

Media Player

HTTPSAP/SDP meta file

StreamingServer

RTP media content

WebServer

RTSP based streaming

For media on demand-like Internet TV

PLAY

PAUSE

STOP

RTP

RTSP streaming

Web Browser

Media Player

HTTP meta file

StreamingServer

RTP media content

WebServer

RTSP commands

rtsp://example.org/example/current.rm

RTSP may also be combained with HTTP streaming !!

HTTP media content(rare)

RTP/RTSP streaming servers example

VLC Darwin Windows Media Server Helix Live555 Feng

Business Model

Free Pay per clip, per time Ads On demand / Live Open / Proprietary (downloadable player) Central / Distributed / P2P

Internet TV and some limitations ...

− Internet network− No QoS− Bandwidth issue− Poor Audio Video Quality− Interrupted Delivery− Content protection− Long Channel Zapping− Poor content− Advertising !!

Internet and multicast ...Internet and multicast ...

Adrian Hornsby

Broadcast Multimedia course – TUT - 2008

Short on Internet (remake)

Internet − world's largest computer network− collection of smaller networks, computers, and

people who use them. − around 28 million people

Until recently, multimedia and internet were not really going together

− Not enough bandwidth, load, errors, traffic ...

Internet and multimedia

First with emails @, files ... Then FTP and Gopher ...

Tradition of sending in one-to-one model Tradition of sending in one-to-one model (unicast) (unicast)

Recently .. explosion of digital information Pictures, Videos, Presentations ...

Need for real-time multimedia communications

One-to-many One-to-many − Bye bye unicast− Welcome multicast over the internet !!

Internet and multicast ...

Early 90's:The Multicast Internet ("the MBone") − region of public Internet connected by IP Multicast

Critical piece of the technology needed to make multiple-person data, voice, and video conferencing on the Internet -- in fact, sharing any digital information -- cheap and convenient. [http://www.savetz.com/mbone/ch3.html]

Mbone .... Virtual network on top of the Internet

Invented by Van Jacobson, Steve Deering and Stephen Casner in 1992.

Minimize the traffic for shared AV conferencing MBONE is free

− Unix based network of mrouters that support IP Multicast

− enables access to real-time multimedia on the Internet

tunneling protocol− encapsulated multicast packets in unicast packets

224.0.0.0 - 239.255.255.255

Mbone in the world ...

But it no longer exist ...

Multiprotocol Extensions for BGP (MBGP)− IETF RFC 2858− allows different address families to be distributed in

parallel− exchange of inter-domain multicast routing

information− Uses PIM to build trees and forward multicast

traffic.

M6bone

What is it ??

− An IPv6 Multicast test network− M6Bone started in July 2001− 24 networks & 45 sites

Goals

− Offer IPv6 Multicast connectivity− Test and develop Ipv6 Multicast − Standardization and recommendation− Deploy advanced service on Ipv6

http://www.m6bone.net

Connections schemes

More details online at http://www.m6bone.net/article.php3%3Fid_article=55.html

Applications

Mbone tools: sdr, vic, rat, nte, wb

Freeamp patches (mp3/rtp)

MIM (mpeg-1/mp3 over rtp)

ttcp and iperf

Multicast beacon (written in java), just worked for ipv6

Available content

Misc vic/rat sessions

TUR (Trondheim Underground Radio)

NRK (Norwegian national broadcasting) radio channels

All global IPv4 multicast sessions (through gateway)

Maybe this time will be a success !!Maybe this time will be a success !!

Thanks ...Thanks ...

Open Discussion !!

Can Internet TV replace traditional TV ? What business model ? All Internet ? .... Other questions ?