Unlike the process of downloading, which transfers whole files to the client workstation, streaming divides the file into small packets of data, which are sent in a continuous stream to the client workstation, which discards the packets after playing them.
Streaming technology evolved in the mid-1990s when network and dial-up speeds increased, computer audio technology became commonplace on desktop computers, and audio compression formats made it possible to reduce the data content of audio files while maintaining an acceptable level of audio quality. Initially, streaming technology was most commonly used to deliver radio broadcasts in real time over the internet. In the mid-1990s, academic libraries recognized the potential of streaming technology to improve the delivery of listening assignments to students, and by 1996, several libraries were digitizing listening assignments and making them available through streaming servers.
Streaming technology offers several advantages over downloading for distributing audio over a network. Digital audio files can be very large (roughly one megabyte of data for every minute of compressed audio encoded at 128 kbps),4.1 and depending on the speed of the network connection, downloading one minute of compressed digital audio can take anywhere from a few seconds to several minutes. Streaming audio allows the user to listen without having to download the entire file. When a user requests an audio stream, the streaming server begins sending packets of data to a buffer--a digital holding tank--on the client workstation, and a second or two later, once the small buffer is filled, the player can start playing. Also, because the player works with only a small part of the file at a time and discards it once it has been played, streaming audio technology discourages illegal copying and distribution of copyrighted material, since the entire sound file is never stored on the listener's computer.
Using streaming audio for listening assignments offers several advantages over traditional delivery methods. Streaming audio technology allows library users to listen to recordings on any computer connected to the internet, and with wireless access points in libraries, in airports, in coffee shops, in hotels, listening can be done practically anywhere. Also, in the past, because only a few people could listen to a sound recording at a time, students often had to wait in line for an assigned recording to become available, even when the library made multiple copies. Streaming audio allows an entire class of students to listen to the same selection at the same time.