Audio Streaming © Nanda Ganesan, Ph.D.

Audio File Features Audio file is a record of captured sound that can be played back –The WAV File is an example Audio files are compressed for storage and faster transmission Requires high bandwidth to transfer across the network and the Internet

The Wav File Format The wav file format is also known as the basic file format –Somewhat similar to the.bmp format for images Requires the highest storage compared to other compressed and streamed file formats –Example: rm, wma etc.

Audio Streaming Concept.WAV.ASF,.WMA Real Producer. RM Windows Media Encoder or Real Producer  PC Audio Format  PC Windows Media Streaming Software

Audio Streaming Step1: Digitize audio –PCM Step 2: Compress the digitized audio –Lowering the audio’s sampling rate –Filtering high frequencies –Performing other waveform transformation Ensure the continuous streaming of audio packets

Pulse Code Modulation Values Sampling Frequency –11,000 Hz for example Sampling depth –8 bits for example Channels –Mono or stereo

Streaming Process Digitize (PCM) Audio Digitized audio Streaming Software Streamed audio

Audio Streaming Advantages Low bandwidth and storage Able to deliver audio in real time over a communication line Efficient and effective delivery of audio over the Internet

Audio Streaming Applications Long-distance or automated seminars and training sessions Internet music Internet radio Streamed audio for a variety of web and CD applications

Audio Format: MPEG Moving Pictures Expert Format –mp3

Audio Format: Apple Related Quicktime and other Macintosh related standards –.qt,.aif,.aifc,.aiff,.mov

Audio Format: Unix Related au snd

Audio Streaming Products Window Media Technologies (Microsoft) Real System (Real Networks) Shockwave Streaming Audio (Macromedia) Linux based streaming products