Audio on the Web

Teaching OntheNet 2002Minneapolis, MNJune 23-25, 2002

What is Streaming Media

• Method to deliver content in Real-Time, allowing content to viewed/listened to as it is being downloaded.

• Actual content resides on a “server”, content is usually not downloaded to students/clients computer

Downloading vs. Streaming57 second clip

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

00:57 (listening)

File Size Comparison0

20406080

100120140160180200

FileSize

(MB's)

Un-Compressed(.wav) formatCompressed(Real Format)

Benefits of Audio on the Web

• Faster playback• No need to download, simply play and listen

• Smaller file size than most formats• Compression removes un-heard information

• Can be stopped/started/restarted• Allows for taking of notes, replaying missed information

• Reduces out-of-date information• Your audio can be updated anytime, anywhere, allowing you to provide your students the most accurate, current information.

Basics of Streaming Media

BANDWIDTH

A Real Player Stream

25 Kbps

Minimum Bandwidth Needed toview this presentation.

This presentation will play on a28.8Kbps connection, but therewill be lots “buffering”.

If connected via a 28.8Kbpsconnection, RealPlayer will not play-back the presentation “smoothly”, browser download will slow-downand checking email will take longer.

Buffering(under ideal conditions)

Buffering(with net congestion, inadequate bandwidth)

Components Needed for Streaming

1. Web Server (IIS, Netscape Enterprise Server, Apache) This can be any regular web server and will typically have all of the front-end files that use-streamed media. It stores and serves all associated text files that point to encoded video/audio files.

2. Web Client Software, a.k.a. Browser (Netscape, Internet Explorer, Opera) This is software on the client computer that accesses the web.

3. Streaming Media Client Software (RealPlayer,Windows Media Player, Quicktime) This software is launched by the web browser and runs as an external application to play & manage streaming files.

4. Streaming Server (RealMedia Server, Windows Media Services, Quicktime) The Streaming Server is a dedicated server with streaming software to serve the encoded video/audio files. It will allow the multiple streaming of media files and access to any portion of any encoded file.

Recording Options

Inputs

• Input to “audio” software, then to Real• Input to Real Producer (or other software)

• Microphone• CD Player (external or internal)• Tape Player• Digital (MP3, MIDI, etc…)

To “Audio” software, then to Real

Benefits• Balance Volume• Remove ‘dead’ space• Add Effects• Can be exported to

multiple formats (Real, Windows Media, etc…)

Disadvantages• Steeper learning curve• Requires more time to

produce• Required more disk

space• More expensive

Direct to Real Producer

Benefits• Easy to use• Minimal learning

curve• Fast• Free Version

Available

Disadvantages• Cannot add effects• Cannot remove errors• Difficult to edit• Difficult to merge

multiple files into one

Real Producer

Uploading files

• File Transfer Protocol (FTP) (Cute, WS_FTP)• Network Drive

LERN

How a Real Server works…

Accessing your audio

• Student clicks on hyperlink in browser(point to .ram or .rm file)

•rtsp://[servername]/[directory]/filename.rm

• Direct link to streaming media file

•http://[servername]/[directory]/filename.ram

•Use for compatibility with older broswers

• audio1.ram points to the streaming media server which allows streaming content to be played

Accessing your audio

Creating Audio Tips• Have a script

• Vary your voice to keep the listeners attention

• When recording, select a quiet place free of transient noises. Position the microphone about 6 to 9 inches away from your lips. Speak across rather than directly into the microphone. This prevents puffs of air from creating popping noises in the microphone, and will yield a higher quality recording.

•When digitizing audio onto the computer you may have a choice of sampling rates and bit depths. 16 bit mono at 22 kHz is usually a good setting.

Questions?

Email the author: johna@lern.org

“… It [the Internet] sic. will become the 21st Century's telecommunications infrastructure. It will become our medium of commerce and education, of research and medicine. It will become a repository of the knowledge, wisdom and creativity of the human spirit. Internet will be there, for everyone.”

(Vinton Cerf, Social, Economic and Regulatory Issues,2000).