Web Radio

Internet radio is a broadcasting service transmitted via the Internet. Not every internet "radio station" has a corresponding traditional radio station. Many internet radio stations are completely independent from traditional ("terrestrial") radio stations and broadcast only on the Internet. Broadcasting on the Internet is usually referred to as streaming.

Because the radio signal is relayed over the Internet, it is possible to access the stations from anywhere in the world -- for example, to listen to an Australian radio station from Europe or America. This makes it a popular service for expatriates and for people who have interests that may not be adequately catered for by their local radio stations (such as country music). Some of the internet radio services offer news, sports, talkback, and various genres of music -- everything that is on the radio station being re-broadcast.

Internet Radio Technology: Streaming

One of the most common ways to distribute internet radio is via streaming MP3 technology, which uses the well-known MP3 music format. The bits are "streamed" over a TCP/IP connection, then reassembled and played within about 2 seconds. Therefore, streaming MP3 radio has about a two-second lag time.

There are three major components to an MP3 stream:

1. Audio stream source 
2. Audio stream repeater (server) 
3. Audio stream playback

There are many methods for creating the audio stream source. Those more technologically savvy may opt for the SHOUTcast service, which utilizes Winamp and the SHOUTcast DSP plugin to deliver MP3 audio at higher bitrates. Other methods include open source technologies such as Streamcast, stream-db, IceS, and MuSE. Using open source stream source tools allows for interesting web interface possibilities like phpStreamcast.

Two of the most popular internet radio networks are Live365 and SHOUTcast. Open source alternatives include Icecast and Xiph.org, which include Ogg Vorbis streamings (that can be played by Winamp and Zinf). Collectively, these internet radio servers list thousands of Internet radio stations covering an ever-expanding variety of genres. The purpose of the server is to repeat the stream source to the audio playback software.

Some sort of audio playback software or hardware, that is capable of reading HTTP data streams, is needed to listen to streaming MP3 audio. Some popular software players are Winamp for Windows, iTunes for Macintosh and Microsoft Windows, and XMMS on Unix/Linux. Listening to internet radio through hardware devices is not so popular, due to the very limited amount of devices which are available. On Internet radio device a list of commercially available devices are mentioned.

There is also an open source codec called ogg which allows streaming using Winamp or Icecast servers.

There are also a small number of web radio programs that allow users to rate the songs they are listening to. This allows a user's music listening choices to be correlated against those of others, as with the programs iRATE radio, Last.fm, and Radio Paradise.

Internet Radio Technology: Podcasting

Audio and video programs resembling those of radio and TV can also now be distributed by Podcasting which can be published by various means including RSS feed and P2P clients.

Internet Radio Technology: History

The first Internet "radio station", Internet Talk Radio, was developed by Carl Malamud in 1993. Malamud's station used a technology called MBONE (IP Multicast Backbone on the Internet). In February, 1995, the first full-time, Internet-only radio station, Radio HK, began broadcasting the music of independent bands. Radio HK was created by Norman Hajjar and the Hajjar/Kaufman New Media Lab, an advertising agency in Marina del Rey, California. Hajjar's method was to use a CU-SeeMe web conferencing reflector connected to a custom created audio CD in endless loop. Later, Radio HK converted to one of the original RealAudio servers. Today, Internet radio stations such as VoyagerRadio utilize the technologies of web services like Live365 to webcast 24 hours a day.

Tuning in to a broadcast like a traditional radio is not possible on internet, so finding different broadcasts has to be done with a search-engine or a website that collects on-line radio broadcasts.

In 1997, Sonicwave, created by producer Edward Lyman, with licensing agreements from BMI and ASCAP, became the first legal internet-only station to broadcast live, 24/7 using RealAudio.

In 1999 a company called MyCaster released a tool that allowed anyone to Netcast in 10 minutes. The MyCaster tool was cleverly simple. It was basically a software MP3 player, similar to Winamp, that as the user listened to music it simultaneously sent a stream to the MyCaster Website. MyCaster then amplified the stream and listed it on its site for listeners to access. The free service allowed even people with little technical skill to easily go live with their own Internet radio station. Like many early Internet radio endeavors, MyCaster succumbed to the dot com bust in 2001.

A new technique for internet broadcasting via P2P technology called Peercasting will hopefully make it easier to start your own station and cut down on bandwidth costs for current broadcasters.

This article is adapted from wikiPedia.com.