Multimedia Streaming
CE00164-3
Module Information
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Module code CE00164-3
Module Title MULTIMEDIA STREAMING
Level 3 (Semester 2)
Credit Value 15
Lecture/Teaching Areas E6
Module Tutor
 Mohamed Abdel Maguid
 Room C207, Tel 01785 353324
 m.m.abd-el-maguid@staffs.ac.uk
 Module Moderator
 Tim Dunning
 Room C206, Tel – 01785 353433
 t.s.dunning@staffs.ac.uk
Accessing documents
Resources
Blackboard for all documents
You will study
 The theory and practice of Media Streaming
 How streaming media is created and delivered to the
world.
 Windows Media Streaming using specialised Media
Servers design to stream high bandwidth media content.
 Computer networks
 Video encoding
 SMIL to integrate presentations and media content.
 Management of media rights, authentication and
conditional access
Assessment
The assessment is to create in pairs a
synchronised media presentation and
streaming it live.
A presentation of it is also required to
demonstrate your understanding of the
theory and practice.
There will also be 2 compulsory multiple
choice tests on Blackboard conducted at
separate times during the term.
Attendance
All students are expected to attend every
week and conduct 4 hours of homework
per week.
The material delivered each week is the
homework and must be studied in time
for the lesson that follows it.
Timetable
Lecture is on Monday 11-12 in E6.
The tutorial is Thursday 1-3 in E6.
You have been given one additional
session to use the E6 lab to practice using
the servers on Wednesday 12-1.
Teaching Plan
 Week 1:
Introduction to module
 Investigating and using Google Video / You Tube
 Week 2:
 Week 3:
Theory of Streaming Media
Introduction to Networking
 Intro to on demand streaming
 Week 4:
Introduction to video coding
 Intro to live streaming
 Week 5:
Principles of encoding for the web
 More Live Streaming
 First multiple choice test
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Week 6:
Week 7:
Week 8:
Week 9:
Digital Media Access Rights – Load balancing
Introduction to SMIL
Introduction to SMIL
Introduction to SMIL
 Second Multiple choice test
 Week 10:
 Week 11:
 Week 12:
Wireless Streaming with Aztec
Flash Streaming
Independent study week
Basic Streaming
What is streamed media?
A) when the complete file is downloaded first
before playback?
B) It is how TV is delivered to the home
C) Or when only a small number of packets of
video required and the computer memory builds
up a few seconds of video and instantly plays I
back?
Answer
It can be A and C
What are the basic requirements for
Streaming media?
Correctly encoded media content
Specialised computer servers
High speed high bandwidth networks
A media player device that can receive the
video stream
Transportation protocols to ensure real
time delivery of information
Basic forms of Streaming
 Progressive Download
 Commonly called download and play
 Issues?
 Video is stored in a temporary file on hard drive thus
occupying space.
 Cannot be sure on what bitrate the file is until it has fully
downloaded. An issue on a low bandwidth connection.
 Can saturate your network connection.
 True streaming
 Advantages?
 Does not occupy any hard disc space
 Efficient streaming
 Does not saturate your network connection
 User controls are available.
Basic Uses and Services
Streaming radio stations
Promotional videos
Short News Articles
Longer video broken up into chapters
Education and entertainment
Offer on Demand Televisions programmes
Multiple languages and subtitles
What devices can be streamed to?
Computers
Mobile Phones
PDA’s
Blackberry’s
Games Consoles
Anything with an Internet connection and a
media player
Week 2 Streaming
What is required to view a stream?
A specific plugin on your device
Plugins include
Windows Media Player
Real Player
Quicktime player
Flash Player
How do you stream?
Media Server
Encoder
Internet
How Does Streaming Work?
1
User clicks on stream link
2
Web Server returns
location of media file
1
2
Web
Server
3
Media
Server
4
5
3
Media player is launched
4
Media player requests
media file from media server
5
Media server sends stream
to media player
6
Media player decompresses
and plays stream
How does it work?
 File encoded and compressed to a smaller
file
 Break it into small packets
 Send them one after the other
 When the packets reach their destination,
they are decompressed and resembled into a
form that can be played
 Playing a music or video file as it is
downloaded from the internet.
 Copy is never stored on the user’s computer.
How does it work? (Cont)
 To maintain the seamless play the packets
are buffered in memory
Process by which the media player downloads a few
seconds of the media file prior to actual playback.
Allows for uninterrupted playback as when buffer
plays more packets are downloaded and queued for
playback
 Streams can be opened before a download is
complete
Organised to be rendered ASAP
Play as data is received
Open Connection
 Streaming media files maintain an open
connection
 Media server and media client negotiate
connection
 Sent over the connection until the entire file has
been received
 Media clients play data over the open
connection
 Is buffered to overcome congestion
Playback Rates
 Streams can be encoded and downloaded at
different bit rates.
 Measured in kbps (kilobits per second).
128 kbps is considered to be CD quality when
using special codecs.
1-2Mbps is considered to be DVD / Broadcast
quality.
 User’s bandwidth determines that maximum
bit rate that can be played.
 Can select the usual connection speed or
give various options
Encoding
 The process of digitizing and compressing a
piece of traditional media into a format capable
of being broadcast over the internet and played
by a computer
 Raw data is typically uncompressed
Big files - Contains all data essential to proper play
 Raw data is then encoded (compressed) to
stream
Encoders use audio and video codecs to compress
data
 Compression is different for audio and video
Codecs
Stands for Compression and
Decompression
Compresses multimedia content prior to
transmission and decompresses upon
playback.
This uses less bandwidth and increases
playback speed.
Users must have the proper media
player to stream each format.
Sound/Music Codecs
MPEG-1 layer 3 (MP3)
8 to 320kbs
Qdesign (Quicktime)
Basic – 8 to 48kbs
Pro – 4 to 128kbs
MPEG4 (v1,v2,v3,v7,v10)
2kbs to 2mbs
MPEG
 MPEG (Moving Picture Experts Group),
develops standards for digital video and digital
audio compression.
 MPEG-1 was designed for coding progressive
video at a transmission rate of about 1.5 million
bits per second. It was designed specifically for
Video-CD and CD-i media.
 MPEG-1 audio layer-3 (MP3) has also evolved
from early MPEG work.
MPEG (Cont)
 MPEG-2 was designed for coding interlaced
images at transmission rates between 1 and
80 megabits per second.
 MPEG-2 is used for digital TV broadcast and
DVD. An MPEG-2 player can handle MPEG-1
data as well.
 A proposed MPEG-3 standard, intended for
High Definition TV (HDTV), was merged with
the MPEG-2 standard
MPEG4 and beyond….
The standard for multimedia for the web
and mobility.
MPEG-4 is able to throw away a lot more
information and to save files 8 to 12 times
smaller than those of MPEG-2.
Divx is based upon MPEG-4
MPEG-4
 Real power of MPEG-4 is the interactivity that
can built into the video file or stream.
 Multimedia producers and software and game
developers can isolate parts of the video for
particular special effects.
 Pocket PC devices and Windows CE already
play back MPEG-4 and related codecs.
Encoding Streaming Video
Choice of formats
Real Video (Helix)
QuickTime
Windows Media
Flash Video Streaming (New up and coming)
Choice of delivery speeds
What connection are you streaming to?
Dial up modem (56Kbps)
ISDN/Dual ISDN (64/128Kbps)
Cable 128 up to 100Mb per sec
ADSL (copper twisted pair up to 16Mbs at least)
T-1 (1.5Mb’s) T-3 45Mbps’s
E-1 (more commonly called 2Mbps pipe)
Considerations for streaming
 Movie size – size affects bandwidth
 Frame rates – broadcast TV is 25fps most
webcasts are lower
 Is it audio, video or both
 Encoding the media – which format
 Making a website which is suitable to play a
streaming file.
 Serving the media
What computer hardware do you need?
A standard web server with the correct
software installed
OR
A specialised media server
Both have streaming capabilities but why is one better than the
other?
• Live Streaming requires a dedicated media server
• A web server is fine for low usage streaming files but
if volume of people wishing to stream from your site is
above 10 at a time you need a media server.
• Media Servers give you much more control for your
streams and offers many more services for your clients.
• Media Servers enable 2 way communication the
client can say rewind your media file (only for unicast).
Web Server V Media Server
Media Servers
Servers needed to serve streams.
In order to stream, a web site must
install media servers into it’s network.
Capacity is typically measured by the
maximum number of concurrent
streams that the server can serve.
Multiple Stream
 From a normal web server
Content has been encoded for one bit rate only
Not really streaming, just being downloaded
TCP will resend lost packets and could cause playback
pauses
 Dedicated media server
Content can be encoded at multiple bit rates and the
server will choose the right one
Server uses proprietary protocol to control content – can
choose best transport
Server is tuned to provide optimum performance under
heavy use – big beefy machine, multiple CPU’s, high
memory and disk drive space.
Media Servers
 Helix Server
Real Networks
 Microsoft Media Server
 Quicktime Streaming Server / Darwin Streaming
server
 Hyperlinks use a linking file
Signals the browser to launch the streaming application
URL is passed indicating the server protocol, media
server, and media file
 RAM / RA – Realnetworks, ASX / WMX for Microsoft
Transmission Models
 Unicast
Streaming between sender and a single recipient
 Multicast
Streaming between sender and multiple specific
recipients
 Broadcast
Streaming between a sender and any receiver
Live and prescheduled content
Some radio and television stations over WWW
Use playlists to automate playback
Basic Networking
Requirements
 A communication protocol (language)
 E.g TCP/IP and UDP
 A networking standard
 Ethernet, the standard for Local Area networks (LAN’s)
 IP addressing
 Each computer is given a unique name to identify it on an Ethernet network.
 The format of an IP address is a 32-bit numeric address written as four numbers
separated by periods e.g 192.168.1.1 for PC no.1, 192.168.1.2 for PC no.2
 Gateway
 Give you access to the Internet (WAN – wide area network)
 Ping
 TTL
 Switches and Routers
 A means of linking computers together
 It filters and forwards network packets that are sent from PC 1 to another PC
Unicast streaming
One to one client server relationship
Like you playing a VCR
Communication channel remains as
packets travel
to client.
Allows the user to use controls like FF, RW
and play.
Unicast Setup
Multicast
Uses watch content (Little bit like watching
TV).
Media server generates one stream that
allows players to connect to it.
Client connects to stream and not server
Replacement packets cannot be resent
Uses special Multicast UDP
Multicast
Networks must be equipped with switches
and routers supporting multicast protocols.
Efficient and cost effective.
1 stream easier to distribute than 1000
Uses Class D IP addressing
In range 224.0.0.0. – 239.0.0.0
Multicast setup
Transmission protocols
UDP V TCP
Protocols
UDP, Multicast UDP and TCP
Rollover Protocols
UDP, TCP and HTTP (MMS automatically does
this when you have setup the server correctly
and so does Real to)
Server Delivery Protocols
 TCP/IP = Transmission control
protocol/internet protocol.
 Dedicated media servers use proprietary
delivery protocols
 Server attempts to provide content over UDP
(User Datagram Protocol)
 If unreliable or firewall then TCP is used
 Allows server to control content
 Content is streamed directly to the viewer and
not saved or cached
Requirements for Streaming
Powerful Networks – the delivery
mechanisms
Reliable Networks
Compressed media files
Transportation protocols
Real Time delivery of information
Digital Rights?
Common Protocols to Learn Basics of
1. TCP/IP – Transmission control/Internet
protocol
2. UDP – User Datagram protocol
3. RTP – Real Time Protocol
4. HTTP- Hyper Text Transfer Protocol
5. RTSP – Real Time Streaming Protocol
6. MMS – Microsoft Media Server protocol
TCP v UDP
Protocols - TCP/IP
 A layer 4 protocol (transport layer)
 Developed by US department of defence
 Error resilient protocol for use on high error rate
networks.
 If packets arrive in wrong order, some are lost or
corrupted it will send a message back for them to be
sent again.
 Problems – high latency, overhead of this guarantee
is the transmission rate e.g Not very quick.
 Used for lossless data packets such as images,
text,etc.
 Packet ordering guarantee.
UDP – User Datagram Packets
 Uses layer 4 protocol. (transport)
 Has little error resilience.
 UDP is fast but packets can arrive in wrong order or it
can lose packets and no way to recover them.
 Problems – unreliable protocol. Packets get lost and can
arrive in the wrong order due to network congestion.
 Used for streaming of some media.
UNICAST, BROADCAST, AND MULTICAST
 The bulk of the traffic on today's networks is unicast:
 Broadcast unicasting wastes bandwidth by sending the data to the whole
network whether or not the data is wanted. Broadcasting can also
needlessly slow the performance of client machines. Each client must
process the broadcast data whether or not the broadcast is of interest.
 Multicasting takes the strengths of both of these approaches and avoids
their weaknesses. Multicasting sends a single copy of the data to those
clients who request it. Multiple copies of data are not sent across the
network, nor is data sent to clients who do not want it. Multicasting allows
the deployment of multimedia applications on the network while minimizing
their demand for bandwidth.
Comparing bandwidths of Multicast &
Unicast
•This following graph compares the network load per client when
unicasting an 8-Kbps PCM audio stream and multicasting the stream
and shows how a multicast saves bandwidth.
Common Problems With Streaming
Poor quality
Screen size is small
Not ‘compelling content’
The internet may not be fast enough
Not broadcast TV Quality
Problems With Streaming (Cont)
 Compression Artifacts
To much raw data could be discarded until
bandwidth delivery requirements are met
Audio quality might become very poor
Video becomes jumpy and poor pixelated
Display size for video is often quite small
 User Datagram Protocol issues (UDP)
Bad packets are removed
Audio will drop and pop
Video will drop or loose frames
Blank frames may be displayed
Problems With Streaming (Cont)
Streaming Connection
Can loose its connection
If connection is lost playback will end and
must be restarted.
If network is congested network will pause or
delay
Popular sites can become unavailable if the
network and servers cannot cope the with
demand
Streaming Formats
Real
RA, RAM, RM
Microsoft
ASF, WMA, WMV
Apple
MOV, QT
Flash
FLV
Streaming Software Comparisons
Real time Encoding
Software
Streaming Server
Solution
Player
Real Producer (small
cost)
Win 2003 with Helix
universal server
installed
Real Player
Windows Media
Encoder (Free)
Win 2003. Media
services free and
part of server
software
Window Media Player
Quicktime
Broadcaster
OS X server.
Streaming built into
it.
Quicktime Player
Real…
RealNetworks
 RealNetworks (previously known as Progressive
Networks) was founded by ex-Microsoft executive Rob
Glaser in 1993
 The first and still most popular of the streaming solutions
 Provides a complete creation, server and player solution
 Helix announced in July 2002
 Streams all formats Real, Mov’s and WMV’s
 Used as the format of choice by BBC radio streaming, the
largest streaming media network in the UK, possibly the
world.
Real One….
www.real.com
Helix
 The Helix Platform
 the first open, comprehensive platform of digital media
products and applications for any format, multiple operating
systems (XP, Linux, Unix, Solaris) and portable devices.
 The Helix Community
 enables companies, institutions and individual developers to
access and license the Helix platform source code in order to
build Helix-powered encoder, server and client products and
other media applications for both commercial and noncommercial use.
 Helix Universal Server
 is a breakthrough product from RealNetworks that for the first
time streams all major media types.Still the only streaming
provider to do so.
Real Networks Solutions
Helix Producer
Content Creator – encodes the
Real Slideshow
Assembles still photos and graphics with
music and sounds
Helix Producer
 RealNetworks Streaming Media creation tool
Encodes existing and live content
Wizard plus point-and-click design tools
 Next generation digital media production tool
for broadcast streaming and download.
 It provides robust, reliable and fault-tolerant
encoding to convert audio and video into
RealMedia format.
 Using RealMedia Events, Helix Producer can
also be used to create synchronized
multimedia presentations for playback within
the RealOne Player.
Helix Producer
Live and/or simulated live video and/or
audio webcasts
On-demand audio and/or video
Synchronized multimedia using a
combination of datatypes (using SMIL)
Produces high quality broadband content
Helix Server
 No longer it is necessary to maintain three
different delivery infrastructures to reach the
largest audience.
 You can deliver all three major media formats
over one delivery infrastructure. When you
have a Helix Server, you have the capability
to deliver media to any individual with a
media player.
 The RealNetworks system architecture based
on the Helix platform has achieved
unmatched performance.
 Supports SMIL
Helix Server – Scaleable Streaming with Surestream
 Combine several different streams into a
single file
 The appropriate bit rate stream is
automatically selected
 Essential for live streaming when you only
wish the customer to click 1 link.
Real Video 10
 • Compatible with all RealVideo 9 decoders – No
RealOne™ Player update
 is needed to play RealVideo 10 content
 • Same Quality at 30% lower bitrate than RealVideo 9
 • Same Quality at 80% lower bitrate than MPEG-2
 • Same Quality at 75% lower bitrate than HDTV
 • Same Quality at 45% lower bitrate than MPEG-4
(ASP)
 • Same Quality at 30% lower bitrate than WMV 9
 • Same Quality at 15% lower bitrate than H.264
HDTV Ready & Home Theater
Experience
 HDTV quality video at <5 Mbps
 Supports all HD formats and resolutions
including 720p and 1080i
 Interlaced support—the RealVideo 10 bitstream
can carry 60 fields a second interlaced content
 New RealAudio Multichannel provides the
ultimate home movie experience through the
encode and decode of 4, 5 and 5.1 channel
audio
Real 10
http://www.realnetworks.com/products/cod
ecs/realvideo.html
See the examples of Real 10
Real Networks Strategy
Leverage player penetration to drive
demand for Real format, software sales,
content distribution and real.com
entertainment portal.
Provide end-to-end streaming solutions
(encoding, hosting, distribution, security,
ad insertion, playback)
Microsoft Media
Microsoft Solutions
 Windows Media Services
Second place in the market
Provides complete solution
Scales up to 9,000 concurrent streams using a
single server – very unrealistic though. Depends on
computer power, network bandwidth, stream
bandwidth etc.
 Windows 2003 server
Media services are built in (different versions)
 http://www.microsoft.com/windows/windowsm
edia/9series/server.aspx
Microsoft Solutions
Windows Media Player
Plays audio / video content
Windows Media Encoder
Produces streaming content from a number
of formats
Windows Media Rights Manager
Supports encryption and licensing of digital
media
Windows Media Player
 Offers consumers the first fully integrated digital
media experience
 playback of CD-quality audio and DVD video
 streaming and downloaded audio and video –
 Designed to be the first digital media player for
everyday consumers, breaking new ground in four
key areas
 All-in-One Integration
 Easy to Use
 The Best Audio and Video Experience
 More Personality
 Basically Windows and Real players offer the same
services.
Microsoft Windows Media Encoder
Encodes existing and live content
Wizard plus point and click design tools
Special screen capture codec
Supports file sizes up to 30 Gb
Supports up to 50 simultaneous streams
from the encoder – dependant on
computer power
Microsoft Windows Media Encoder
Produces high quality broadband content
Near VHS at 400 kbps
Near DVD at 750 kbps
See the new HD WM9 in action – load
examples
Same filters at Real Producer –
deinterlace etc
Production Tools and Views
Sessions can be saved as profiles
Real time creation statistics
http://www.microsoft.com/windows/windowsmedia/9series/
encoder/default.aspx
Windows Media Services
 Integrated with Windows 2000
Scales up for Internet and intranet use
Utilises features of Windows 2000
Supports media bit rates from 28kbps to 20mbps
 Built in administration wizards and interfaces
 “Intelligent Streaming” encoding
Multiple bit rates streams saved and served from
one file
 Other advantages
Digital Rights Manager
Server Side APIs – Multicast capabilities
Microsoft Strategy
Trying to dominate the media player
market as it did the browser market.
Provides players and server software for
free.
Server: Bundled with 2000 and 2003.
Player: Bundled with Windows and IE.
Real Networks vs. Microsoft
 No clear winner will emerge soon.
Both Real and Microsoft each have very strong player
and server penetration.
 Content providers wishing to reach the largest
audience will continue to encode their content in
both formats and implement multiple streaming
servers.
 In the near-term, Real should be able to
maintain its strong position and pricing power
despite Microsoft’s challenge.
Windows Media 9
Says best quality
http://www.microsoft.com/windows/windowsme
dia/9Series/GettingStarted//
Must not forget Apple….
Apple Solutions
Quicktime
Originally extension of the Mac OS
Encorporates text, graphics, audio and
video into a single format
Can be viewed with a time element
QT or MOV format available on Windows
PC’s
Apple Solutions
 Quicktime Player
Displays video, sound, animation, text and music.
Also 360 degree panaromas
 Quicktime Pro
Create, open, edit and save movies and audio
Resize movies and create streaming media
 Quicktime Streaming Server
Serves Quicktime files stored on the server
Supports 2000 streams to Quicktime users
Requires Mac OS server
Quicktime
 http://www.apple.com/quicktime/products/qt/
Quicktime Streaming Server
 Instant-on provides enhanced overbuffering of
data, dramatically reducing buffer time for
broadband users.
 Serves to any standard MP3 player such as
iTunes, WinAmp, or QuickTime Player
 Web-based interface for local and remote
administration
 Supports QuickTime (.mov), MP3 audio (.mp3),
or MPEG-4 (.mp4) files
Quicktime (Cont)
Allows you to create simulated live
broadcasts with Playlist Broadcaster,
perfect for creating your own Internet radio
station
Supports up to 4,000 simultaneous
streams
Supports both unicast or multicast streams
Competitive Landscape
RealNetworks and Microsoft continue to
battle for market leadership.
RealNetworks RealPlayer/Real One:
150 million registered downloads
85% market share
Microsoft Windows Media Player:
100 million registered users
Catalysts For Streaming Adoption
 Broadband Penetration
 Availability of streaming content
The proliferation of streaming creation and playback
tools lowers streaming costs.
Content providers are beginning view the Internet as
a new distribution channel.
 Formats are becoming transparent to the
user.
 New technologies that support payments.
Ad insertion.
Billing, payment and tracking systems.
Digital Rights Management.
Broadband Penetration
The estimated 12 million
users through college
broadband networks are not
included in these figures.
The global number of broadband subscribers reached 263.8 million in Q3 of
2006. In 2006, Ofcom stated 11.5 million households subscribe to broadband
and the number is rising rapidly.
References
 http://www.measurecast.com/
 http://www.streamingmediaworld.com/
 http://www.streamingmedia.com/
 www.shoutcast.com
 http://www.penguinradio.com/penguin/
 http://streamingmedialand.com/
 http://www.streamingmag.com/
 http://www.internetradioindex.com/i-probe/ip_radio.html
 http://www.crosscut.net/streaming.html
 http://www.doit.wisc.edu/streaming/
 http://www.manifest-tech.com/media_web/index.html