1. 12
Media Streaming

2. What is Streaming Media?
The delivery of audio/video/data between a server and a client (user), as a continuous digital stream
Eliminates waiting for an entire file to download
Content is converted to digital files sent over the internet as data packets.
Playback begins as soon as first packets arrive or as requested by the end user
No impact on end-user’s computer
Leading architectures: RealMedia, Windows Media, QuickTime

3. It’s a Challenge
Uncompressed digital video produces data at the rate of 27 MB/sec (1.6 GB/min)
A challenge to store
A challenge to transport

4. Factors in Architecture Selection

5. Streaming Media Formats
Major player formats
Real Networks
Real Media Player – RM
Microsoft
Windows Media Player – WMV
Apple
Quicktime Player – MOV
Other formats
Audio downloads – MP3
Capture and editing - AVI
Flash and animation - SWF
CD audio playback – CDA, WAV

6. Things to Consider Identify your user audience Player compatibility
Are they using PC or Mac
Offices, Dorms, Computer Labs, Homes
Wireless and other mobile devices
Internet Connection
Low speed – 28kbps to 80kbps
High speed – 80kbps to 300kbps
Broadband – 300kbps to 1.0mbps
Audience members
Staff, Dept. Admins, Managers, Directors
Anonymous users on WWW

7. Things to Consider Media delivery Network Other On-Demand
Live Webcasting
CD-ROM, DVD
Network
User connectivity
Firewalls, multicast enabled routers
Other
Password restrictions
E-Commerce
Media reports on viewer usage

8. On-Demand content and live broadcasts
Streams on demand
File-based Streaming
Available to users at any time, and are sent on demand.
Live Streaming
Live broadcast event
Encoder…

9. Streaming Media Options
Encoding
Choosing a format
Real Media
Windows Media
Quicktime
Determine a window size
(Width x Height in pixels)
160x120
240x180
320x240
Even larger

10. Streaming Media Options
Encoding
Bitrate selection
Single rate - 28k, 56k, 120k, 200k, 400k
One stream per bitrate
One encoded file for each user’s connect speed
One URL for each connect speed
Multirate – (28k-56k-200k)
Real - SureStream
Windows - Intelligent Stream
Quicktime - Alternate Movies
One encoded file can reach multiple connect speeds
Server finds optimum connect speed and adjusts as network bandwidth usage changes
Only one url needed for all connect speeds
Larger file size for archive media

11. Streaming Media Options
Authoring
Include powerpoint slides sync’d to video
Insert graphics, images, logos
Add URL links to other sites or content
Create a URL to play only parts of the media
Create a playlist within one URL to stream multiple clips or media files
Set player commands, end-user controls
Pop-up or embedded player

12. Streaming Media Options
Indexing
Assign keyframes to your content media
Allows you to create smaller segments of your media and store them as clips
Add keywords to clips for users to search your media from a website
Convert speech, closed captioning and ppt slides to text for searching
Save clips in a playlist and share them with other users

13. Streaming Media Options
Webcasting
Live presentations over the internet
One multicast stream to many users
Include powerpoint or other rich media
Hosting
On demand playback of archived media
Multiple streaming server platforms
Unlimited streams
Low storage costs
No impact on your own network
No hardware resources to maintain

14. Combining Media Limitations
Web browsers are not designed to fully support multimedia features
Limited coordination of media elements

15. The Problem Lots of Bits Not All Bits are Equally Important
Images, audio and video are beyond Internet design specs
Results in space/ time constraints at:
the server
the network( s)
the client
Not All Bits are Equally Important
Time between samples often more important than bits in sample,
for example lip synchronization (but not always...)
Content may be Distributed Across Network
Need to synchronize presentation
Objectives
Add synchronization to the Web
Allow interoperability
Use declarative format, preferably text — thus XML

16. Solution Use of a single timeline for all media
Creation of time-based multimedia delivery over the web
Synchronization
Coordination

17. What Is SMIL?
SMIL stands for Synchronized Multimedia Integration Language
SMIL is pronounced "smile"
SMIL is a language for describing audiovisual presentations
SMIL is easy to learn and understand
SMIL is an HTML-like language
SMIL is written in XML
SMIL presentations can be written using a text-editor
SMIL is a W3C standard
SMIL 2.0 August 2001

18. What Is SMIL?

19. A Simplified SMIL Example
<body>
<seq repeatCount="indefinite">
<img src="image1.jpg" dur="3s" />
<img src="image2.jpg" dur="3s" />
</seq>
</body>
</smil>

20. What Can SMIL Do?
SMIL can be used to create Internet or Intranet presentations
SMIL can be used to create slide show presentations
SMIL has been described as the Internet answer to PowerPoint
SMIL presentations can display multiple file types (text, video, audio...)
SMIL presentations can display multiple files at the same time
SMIL presentations can display files from multiple web servers
SMIL presentations can contain links to other SMIL presentations
SMIL presentations can contain control buttons (stop, start, next, ...)
SMIL has functions for defining sequences and duration of elements
SMIL has functions for defining position and visibility of elements

21. SMIL Files
A SMIL file contains all the information necessary to describe a multimedia presentation
SMIL files are stored with the extension *.smil
A SMIL file contains the following:
The layout of the presentation
The timeline of the presentation
The source of all multimedia elements

22. How to Play a SMIL File?
You will need a SMIL player. Different SMIL players can be found
RealOne Platform by RealNetworks has full support for SMIL 2.0
SMIL Player by InterObject supports the SMIL 2.0 Basic Profile
With Internet Explorer 5.5 or later, SMIL elements can be inserted into HTML files
This way any SMIL presentation can run over the Internet as standard HTML files

23. SMIL in HTML Adding References
Adding a "time" namespace definition to the <html> tag
Adding an <?import> element to import the "time" namespace
Adding a <style> element to define the class "time"
<html xmlns:time="urn:schemas-microsoft-com:time">
<head>
<?import namespace="time" implementation="#default#time2">
<style>.time {behavior: url(#default#time2)}</style>
</head>
<body>
<time:seq repeatCount="indefinite">
<img class="time" src="image1.jpg" dur="3s" />
<img class="time" src="image2.jpg" dur="3s" />
</time:seq>
</body>
</html>

24. SMIL Timing time formats: Duration When To Start? hh:mm:ss.f
number [h|min|s|ms]
wallclock (YYY-MM-DDThh:mm:ss+zone)
Duration
The duration (dur="5s") attribute
When To Start?
The begin (begin="2s") attribute

25. SMIL Sequence
<seq> - the most common SMIL element - defines a sequence
The <seq> element can have a number of attributes:
begin, dur, repeatCount
<html xmlns:t="urn:schemas-microsoft-com:time">
<head> <?import namespace="t" implementation="#default#time2"> <style>.t {behavior: url(#default#time2)}</style>
</head>
<body>
<t:seq repeatCount="indefinite">
<h2 class="t" dur="1s"> I will display for one second</h2>
<h2 class="t" dur="2s"> I will display for two seconds</h2> <h2 class="t" dur="3s"> I will display for three seconds</h2> </t:seq>
</body>
</html>

26. SMIL in Parallel
Objects inside the <par> element will be played at the same time
Attributes: begin, dur, endsync= "first"|"last"|id(clip), repeatCount
<html xmlns:t="urn:schemas-microsoft-com:time">
<head> <?import namespace="t" implementation="#default#time2">
<style>.t {behavior: url(#default#time2)}</style>
</head>
<body>
<par>
<t:audio src="liar.wav" repeatCount="indefinite" type="wav" />
<t:seq repeatCount="indefinite">
<h2 class="t" dur="1s"> I will display for one second</h2>
<h2 class="t" dur="2s"> I will display for two seconds</h2>
</t:seq>
</par>
</body>
</html>

27. SMIL Transitions
IE 6 supports transitions based on the SMIL 2.0. Transitions are implemented with the element <transitionfilter>
Attributes: type, begin, mode, from, to
Transition Filters
fade, barnDoorWipe, barWipe, clockWipe, ellipseWipe, fanWipe, irisWipe, pushWipe, slideWipe, snakeWipe, spiralWipe, starWipe
<t:transitionfilter targetelement="keyb" type="clockWipe" begin="keyb.begin" dur="2s" />
<img id="keyb" class="t" src="pic_keyb.jpg" dur="4s" width="128" height="107" />

28. SMIL Media Elements
<animation> <audio> <brush> <img> <param> <ref> <text> <textstream> <video>
Attributes: erase src type
<html xmlns:t="urn:schemas-microsoft-com:time">
<head>
<?import namespace="t" implementation="#default#time2"> </head>
<body>
<t:video src=" repeatCount="indefinite" type="wmv" />
</body>
</html>