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Streaming Media

a presentation byFlorian Seidel

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Agenda

• What is Streaming Media?– idea– alternatives– comparison

• How does Streaming Media Work?– broadcasting– bandwidth– buffering– quality

• Needed Components for Streaming• Quiz

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The first idea

• displaying content like text, graphics, links, etc. is easily realizable with standard browser

• displaying audio/video data adds the time aspect which blows up the file size and the download time

• another solution was needed

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Traditional Method of Media Delivery• Normal Downloading

– Entire file is delivered to client’s computer and saved to the hard disk (Temporary Internet Files folder)

– In most cases, the media cannot be played until the entire file is downloaded

– Quality is always assured

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Advantages of Traditional Method• A downloaded file is available for

later use by the user • Downloaded media can provide

higher image quality if needed• A downloaded media file can be

stepped frame by frame• No special software needed

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Another idea

vs

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Another idea

• Streaming– Only a small portion of the file is

downloaded before the file can be played (buffer)

– The media plays as it is being delivered in the background

– Different quality (bit rate) streams are sent to the user depending on the limits of the internet connection.

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Advantages of Streaming• Streaming files are not saved to

your hard disk • After being played, the data is

discarded saving disk space• Anyone with a network connection

can view a multimedia file through the internet (at different quality levels)

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How Does Streaming Work?• Uses special standards-based codecs and

protocols to deliver multimedia information over a network

• RTSP (Real-Time Streaming Protocol)– Control Protocol to handle bandwidth and error control

• RTP (Real-Time Packet)– Standards-based packet (companion to RTSP)

• CODECS (that use RTSP\RTP)– Real: RM, RA, RT– MS: ASF, WMA, WMV– Apple: MOV (most)

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Unicast vs. Multicast

Each client has an individual stream.

Each client uses one stream.

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Example of Streaming Advantage

Total time to Listen to File

0 20 40 60

Connection

Speed

56K

Time (in minutes)

Streaming

Dow nloading

24 min. (download) + 00:57 (listening)= 24:57 min.

00:57 (listening)

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Bandwidth

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A Real Player Stream

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Bandwidth sufficiency

• Minimum bandwidth needed to view this presentation

• This presentation will play on a 28.8Kbps connection, but there will be a lot of “buffering”.25 Kbps

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Bandwidth insufficiency

• If connected via a 28.8Kbps connection, RealPlayer will not playback the presentation smoothly, browser download will slow-down and checking email will take longer.

40 Kbps

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Buffering - with insufficient bandwidth

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Buffering - under ideal conditions

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Components for Streaming• Web Server (IIS, NES, Apache, etc.)

– stores and serves the multimedia files– stores text files that point to encoded

media files

• Web Client (any browser)– accesses the internet– lauches the Streaming Media Client

Software

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Components for Streaming• Streaming Media Client Software

(RealPlayer, Windows Media Player, QuickTime)– launched by web browser– decodes, plays and manages streaming media

files

• Streaming Server (RealMedia Server, Windows Media Services, Quicktime)– runs streaming software– serves encoded multimedia files

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In conclusion

• Streaming Media is a method to deliver and play multimedia data in real-time

• Saves disk space as processed data is discarded after use

• Time saving compared to download-before-playing approach

• Quality depends on bandwidth, but is leveled out through buffering

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Recommended Sites

• for internet radio station search:– www.radio-locator.com

• for internet radio developers:– www.howstuffworks.com

• for people interested in streaming media:– www.streamingmediaworld.com

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Almost there...

The Quiz

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Quiz

• Question 1:– Name some differences between

traditional downloading and streaming of multimedia files

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Quiz

• Question 2:– Name some advantages of streaming

media.

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Quiz

• Question 3:– Name components for working with

streaming media– Describe their basic functionality

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End of Presentation

Thank you for your attention