An Internet radio device (IRD), also commonly called network music player is a hardware device that autonomously receives and plays music from a computer, Internet radio stations or online music services via the home network.
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Background
Before audio compression (data) technology (compression of audio data rather than analog audio level compression) took the world by storm in the past decade, most digital music was sold on CDs. CD audio is an uncompressed form of digital audio file. Because uncompressed music files are large, they are impractical to transmit across the Internet quickly or to carry around on your portable music player.
With the advent of portable music player / MP3 player and the convenience of converting and compressing CD music into music file by the computer, almost all music distributed today is in digital format and stored as audio files on computer. The most common formats are .MP3, .WMA, RealAudio and .AAC format. There are many other different ways to compress a music file. But the industry’s generic term MP3 will be used hereafter to represent all digital compressed audio formats. Network distribution uses a variety of protocols of which HTTP, Shoutcast, WMS, RTSP are the most common.
Compressed music has become the music format du jour and with good reasons:
- It is easy to store and to carry around / you can store a large amount of music
- The transfer online is very fast compared to uncompressed formats
- Songs are tagged and easy to find
- It is easy to share with friends.
When MP3 music was just getting popular a decade ago, the only way to enjoy the music was through the MP3 player software on a computer. While the computer can help source and store music it was never intended to provide the quality of a real hi-fi system.
In a continuously growing, evolving and increasingly converging multimedia landscape, there are a lot more choices with the different digital audio MP3 players available in the market, and docking stations have been introduced to playback the music with a better sound quality.
But unlike the computer which is usually the central storage of the MP3 music at home, the MP3 players have less storage to store the entire music collection. Hence the need for other solutions.
One solution is the network music player.
The network music player is connected to your home wireless router (often Wi-fi B standard or Wi-fi G standard compatible). The router is also connected to the home network and the computer. Via this wireless connection, the network music player can access the user’s collection of music on the computer or on a Network-Attached Storage (NAS) device, or access Internet radio stations and online music services.
Audio Streaming
Audio streaming is one way of transmitting audio files on a continuous feed to a network music player. A common way today is to stream the audio from the computer to a network music player over the more convenient wireless technologies such as Wi-fi in a networked environment.
The computer, which is typically used for storing the music file, acts as a music server by means of server software, often compliant to DLNA (Digital Living Network Alliance) standard. And the network music player is a typical receiver which starts playing an audio file as soon as some of the data has been received so that one doesn’t have to wait for the entire audio file to finish downloading.
The MP3 music file is streamed to the network music player in digital format, commonly in the original MP3 format. Therefore, the audio details of the MP3 music are sent wirelessly in the home to the network music player as it is stored on the computer and without loss.
The MP3 music file are then converted back into audio signal by the network music player and played. As the MP3 music files are organized by the music server on the computer, the information is also sent to the network music player where user can see all the music track information. Many companies working active in bringing Internet radio into devices are organized in the Internet Media Device Alliance IMDA. In addition to the home networking standards of DLNA, IMDA compatibility standards dedicated to all aspects of Internet radio distribution.
Internet Radio
Internet being reachable to different places in the world, so does Internet radio. It has expanded enormously with an estimated 13,000 stations currently available, including many traditional FM /AM simulcasting their content over the Internet. It is estimated that the number of people listening to Internet radio will grow 200% to 147.5 million by 2010.
Online music services
Online music services usually offer millions of songs and thousands of artists for users to choose from.
Network music players that support online music services let users access this vast selection of music tracks.
Examples of online music services : Napster, Rhapsody, Last.fm, Pandora, RadioTime, Live365,Slacker, Sirius Satellite Radio, Radio IO, MP3tunes...
Station directory services keep a current list of active Internet radio stations, their URI and streaming formats and list them sorted by genre, location, language and other criteria. Many devices use either proprietary vendor-specific station list servers or dedicated directory services from vTuner, streamfinder and others. Devices based on directory services can offer the user customized direct access to [1] more than 10,000 active Internet radio stations from around the world.
Categories
There are generally two types of network music players:
- Those without speakers that need to be connected to an audio system in order to listen to the music
Examples of commercial devices are the Philips Streamium NP1100 and NP2500, Logitech Squeezebox and the Roku SoundBridge.
- Those with their own speakers
Examples of commercial devices are the Terratec Noxon family, Philips Streamium NP2900 and the Logitech Squeezebox Boom. Also many higher end audio devices such as AVRs and Sytems from Denon, Pioneer and Onkyo include Internet radio capability
Hardware
Network music players usually have:
- Broadband connection: an Ethernet and/or Wi-Fi network interface, with TCP/IP support for access to the Internet
- USB port , where the user can connect an external MP3 player like iPod or external harddrive for MP3 files
- LCD display, remote control
- Built-in amplifier/speaker, or AUX-out port, that can be used to connect to a HiFi or similar audio device
- Rechargable batteries for mobility with internal charger integrated
- Favorite streams & contents can be saved as presets
Some devices also have:
- Memory card reader: SD or even SDHC card
- XLR connectors
- (MP3) stream encryption
- Possibility to be built in a 19 inch rack
- Dialup
Alternative
A low-cost substitute for an Internet radio device can be set up, using nothing but a simple FM radio transmitter and an FM radio receiver. The FM transmitter is plugged into the computer's headphone jack, and set to an unused frequency. Then, the FM radio receiver is set to the transmitter's frequency. This arrangement can be used to listen to Internet radio, music downloads, and Youtube videos, without the need for a 802.11 network.
FM transmitters are widely available on the market today, and are often touted as a way for consumers to listen to their iPods through their car radios. One can find one of these devices on the Internet for $50 or less.
The legality of such devices varies from country to country.
See also
References
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
