Streaming is digital data constantly delivered by a streaming provider which is then received by & presented to the end-user. The distinction is usually applied to media that are distributed over networks since most other delivery systems are either inherently streaming (e.g. live radio & television) or inherently non-streaming (e.g., a book, BluRay, DVD, CD).
The name refers to the delivery method of the medium rather than to the medium (or carrier) itself. Music streaming involves:
1. Music is converted (ripped) into computer data (digital data packets) & stored by the user on a server. Or supplied as digital data packets via the internet.
2. Then digital data packets are sent on demand from server to player (often called a streamer).
3. These digital data packets are then reassembled into digital audio data (rendering), usually within the streamer.
4. This digital audio data is then converted into an analogue audio signal by a DAC (Digital to Analogue Converter).
5. And finally the analogue audio signal is connected for playback via a normal amplifier & speakers.
Streaming can be delivered via many different carriers.
So a server of digital data packets could stream across:
1. a digital cable (coax or optical)
2. a wired network (ethernet)
3. a wireless network (wireless router or other b, g, n device, Bluetooth, Cleer, etc)
4. a standard house mains supply (ethernet over mains).
And Internet Radio?
Many streamers are equiped with iRadio - ie they automatically connect to specific internet radio servers on the internet which provide access to thousands of radio stations from around the world. Constantly updated with new stations these are received similarly to DAB or FM stations and can be saved in pre-sets. The quality at it's best can be significantly better than DAB.
And finally UPnP?
Universal Plug and Play is an open network standard that enables audio servers & players (streamers) connected to the same network to communicate automatically, with no setup required.
This means that a UPnP compliant streamer/server will automatically find all the shared music on the network, wherever it is stored, and make it available to play.
And how do I control & play my music?
1. a dedicated supplied remote control
2. a wireless remote device like an iPad, iPhone, iPod Touch
3. a laptop/PC/MAC.
A normal CD player is a self contained device with it's own remote control (normally line of sight Infra-Red). A streamer/player can also have it's own remote control - plus because the music is often streamed over a home wired or wireless network - it can additionally be controlled by any device able to connect to that network.
And because streaming can deal with multiple packets of digital data then more than one piece of music can be streamed simultaneously to different/multiple players and control devices.