Friday, December 30, 2005

Digital audio player

A digital audio player (DAP) is a device that stores, organizes and plays digital music files. It is more commonly referred to as an MP3 player (because of that format's ubiquity), but DAPs often play many additional file formats. Some formats are proprietary, such as MP3, Windows Media Audio (WMA), and Advanced Audio Codec (AAC). Some of these formats also may incorporate restrictive digital rights management (DRM) technology, such as WMA DRM, which are often part of certain paid download sites. Other formats are completely"patent-free or otherwise open, such as Ogg Vorbis, FLAC, and Speex (all part of the Ogg open multimedia project).

There are three main types of digital audio players:

* MP3 CD Players - Devices that play CDs. Often, they can be used to play both audio CDs and homemade data CDs containing MP3 or other digital audio files.
* Flash-based Players - These are solid state devices that hold digital audio files on internal or external media, such as memory cards. These are generally low-storage devices, typically ranging from 128MB-4GB, which can often be extended with additional memory. As they are solid state and do not have moving parts, they are very resilient. Such players are generally integrated into USB keydrives.
* Hard Drive-based Players or Digital Jukeboxes - Devices that read digital audio files from a hard drive. These players have higher capacities, ranging from 1.5GB to 100GB, depending on the hard drive technology. At typical encoding rates, this means that thousands of songs — perhaps an entire music collection — can be stored in one MP3 player. The Apple iPod and Creative Zen are examples of popular digital jukeboxes.

History

The precursors to DAPs were portable CD players and Mini disc players (neither being generally considered a "digital audio player"). Non-mechanical DAPs were introduced following the popularity of the precursors.

The first non-mechanical digital audio player in the world was created by SaeHan Information Systems in 1997. The MPMan F10 was later OEMed to the American market through Eiger Labs. The first non-mechanical digital audio player on the American market was the Eiger Labs MPMan F10, a 32MB portable that appeared in the summer of 1998. It was a very basic unit and wasn't user expandable, though owners could upgrade the memory to 64MB by sending the player back to Eiger Labs with a check for $69 + $7.95 shipping.

The second DAP was the Rio PMP300 from Diamond Multimedia, introduced in September 1998. The Rio was a big success during the Christmas 1998 season as sales significantly exceeded expectations, spurring interest and investment in digital music. The Recording Industry Association of America soon filed a lawsuit alleging that the device abetted illegal copying of music, but Diamond won a legal victory on the shoulders of Sony Corp. v. Universal City Studios and digital audio players were ruled legal devices.

Other early DAPs includes Sensory Science's Rave MP2100, the I-Jam IJ-100, and the Creative Labs Nomad. These portables were small and light, but only held enough memory to hold around 7 to 20 songs at normal 128 kbit/s compression rates. They also used slower parallel port connections to transfer files from PC to player, necessary as most PCs then used the Windows 95 and NT operating systems, which did not support the then newer USB connections well enough to be considered for use. When in the year 2000 USB became more common, most (if not all) players adopted the USB standard.

By the end of 1999, Compaq made a significant improvement in DAPs' space limitations by using a laptop hard drive for song storage rather than low-capacity flash memory. The Personal Jukebox (PJB-100), manufactured under license by HanGo Electronics, had 4.8GB of storage space, which held about 1200 songs (or 100 CDs, hence the name PJB-100), and was the beginning of what would be called the jukebox segment of digital audio players. This segment eventually became the dominant type of DAP.

Also, at the end of 1999, the first in-dash digital audio player appeared. The Empeg Car (renamed the Rio Car after it was acquired by SonicBLUE and added to its Rio line of MP3 products) offered players in several capacities ranging from 5GB to 28GB. The unit didn't catch on as SonicBLUE had hoped, however, and was discontinued in the autumn of 2001.

In 2000, iRiver released their first digital audio device.

The arrival of Apple Computer's iPod in 2001, combined with the iTunes software that all but created the legal-music-download business, greatly expanded the market. Since then a number of new digital audio players became available.

Equipment

Generally speaking, digital audio players are portable, employing internal or replaceable batteries and headphones, although users often connect players to car and home stereos. Some DAPs also include FM radio tuners . Many players can encode audio directly to MP3 or other digital audio formats directly from a line in audio signal.

A number of manufacturers now produce Network MP3 players. These tend to be non-portable devices which have no storage of their own. Instead, they connect to a home ethernet network, and receive a digital audio stream from some computer on the network. They are designed to connect to a home stereo, and are operated with a remote control. Slim Devices, Roku, and cd3o each produce a Network MP3 device.

Devices such as CD players can be connected to digital audio players (using the USB port) in order to directly play music from the memory of the player without the use of a computer.

Modular keydrive players are composed of two detachable parts: the head (or reader/writer) and the body (the memory). They can be independently obtained and upgraded (one can change the head or the body; i.e. to add more memory).

Usage

As digital audio players have spread, new uses have been found for them. This includes podcasting, in which radio-like programs, or even TV-like video feeds, are automatically downloaded into the device to be played at the owner's convenience. Even a low-capacity digital audio player can store several hours of podcasts.

Audio acquisition

Most, if not all, digital audio players can play music that has been ripped from Compact Discs via computer. In addition to ripped CD tracks, many digital audio players can accept downloaded music from online music stores. However, due to the complexity of DRM, not all audio file formats will play on certain digital audio players. Some proprietary audio file formats will also restrict users from transferring songs to non-compatible digital audio players.

Major brands of digital audio players

* Creative NOMAD/Creative Zen/MuVo line from Creative Technology
* iPod from Apple
* Walkman from Sony
* ilo from Go Video
* iAudio from Cowon
* DIVA from Daisy Multimedia
* Dell Digital Jukebox ("Dell DJ") series from Dell
* S1 MP3 Player, generic chinese MP3 players
* Rio (discontinued after August 2005)
* Archos
* IOPS
* iRiver
* GigaBeat from Toshiba
* m:robe from Olympus
* mpio
* Yepp from Samsung
* mobiBLU
* Lyra from RCA

source : http://en.wikipedia.org/

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