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Multimedia Streaming
CE00164-3
Module Information
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 [email protected]
Module Moderator Tim Dunning Room C206, Tel – 01785 353433 [email protected]
Accessing documents
ResourcesBlackboard 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: Theory of Streaming Media Week 3: 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
Week 6: Digital Media Access Rights – Load balancing Week 7: Introduction to SMIL Week 8: Introduction to SMIL Week 9: Introduction to SMIL
Second Multiple choice test Week 10: Wireless Streaming with Aztec Week 11: Flash Streaming Week 12: 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 contentSpecialised computer serversHigh speed high bandwidth networks A media player device that can receive the
video streamTransportation 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 stationsPromotional videosShort News ArticlesLonger video broken up into chaptersEducation and entertainmentOffer on Demand Televisions programmesMultiple languages and subtitles
What devices can be streamed to?
ComputersMobile PhonesPDA’sBlackberry’sGames ConsolesAnything with an Internet connection and a
media player
Week 2 Streaming
What is required to view a stream?
A specific plugin on your devicePlugins include
Windows Media Player Real Player Quicktime player Flash Player
How do you stream?
Encoder
Media Server
Internet
2
2 Web Server returnslocation of media file
1 User clicks on stream link
1
How Does Streaming Work?
3 Media player is launched
3
5
5 Media server sends stream to media player
6 Media player decompresses and plays stream
Web Server
4 Media player requests media file from media server
4 Media Server
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 serverReplacement packets cannot be resentUses 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 TCPProtocols
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 filesTransportation protocolsReal Time delivery of informationDigital 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 qualityScreen size is smallNot ‘compelling content’The internet may not be fast enoughNot 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 non-commercial 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 videoSynchronized 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/codecs/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/windowsmedia/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 contentWizard plus point and click design toolsSpecial screen capture codecSupports file sizes up to 30 GbSupports 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
examplesSame filters at Real Producer –
deinterlace etcProduction 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/
windowsmedia/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 elementQT 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
