A
portable media player (
PMP) or
digital audio player, (
DAP) is a
consumer electronicsConsumer electronics are electronic equipment intended for everyday use, most often in entertainment, communications and office productivity. Radio broadcasting in the early 20th century brought the first major consumer product, the broadcast receiver...
device that is capable of storing and playing
digital mediaDigital media is a form of electronic media where data is stored in digital form. It can refer to the technical aspect of storage and transmission Digital media is a form of electronic media where data is stored in digital (as opposed to analog) form. It can refer to the technical aspect of...
such as audio, images, video, documents, etc. the data is typically stored on a
hard driveA hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
,
microdriveMicrodrive is a brand name for a miniature, 1-inch hard disk designed to fit in a CompactFlash Type II slot. The release of similar drives by other makers has led to them often being referred to as 'microdrives'...
, or
flash memoryFlash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
. In contrast, analog
portable audio playerA portable audio player is a personal mobile device that allows the user to listen to recorded audio while mobile. Sometimes a distinction is made between a portable player, battery-powered and with one or more small loudspeakers, and a personal player, listened to with earphones.-History:Portable...
s play music from cassette tapes, or records. Often digital audio players are sold as
MP3 players, even if they support other file formats. Other types of electronic devices like cellphones,
internet tabletNokia Internet Tablets is the name given to a range of Nokia mobile Internet appliances products. These tablets fall in the range between a personal digital assistant and an Ultra-Mobile PC , and slightly below Intel's Mobile Internet device .- Maemo :Nokia Internet Tablets run the Debian...
s, and
digital cameraA digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...
s are sometimes referred as PMPs because of their playback capabilities. This article however focuses on portable devices that have the main function of playing media.
History
The immediate predecessor in the market place of the digital audio player was the portable
portable CD playerA portable CD player is a portable audio player used to play Compact Discs. The first audio player released was the D-50 by Sony. The D-50 was able to play/pause, stop, rewind, and fast forward music all in one device...
and prior to that, the
personal stereoThe personal stereo is the term given to a portable audio player using an audiocassette player. This allows the listening of music through headphones while a person is mobile. The first personal stereo was the Stereobelt invented and patented by Andreas Pavel in 1977. Pavel attempted to...
.
IXI
British scientist
Kane KramerKane Kramer is a British inventor and business man. He is credited with the initial invention of the digital audio player, in 1979.-Invention of the DAP:...
designed one of the earliest digital audio players, which he called the IXI. His 1979 prototype was capable of approximately 3.5 minutes of audio playback but it did not enter commercial production. His UK patent application was not filed until 1981. Apple Inc. hired Kramer as a consultant and presented his work as an example of
prior artPrior art , in most systems of patent law, constitutes all information that has been made available to the public in any form before a given date that might be relevant to a patent's claims of originality...
in the field of digital audio players during their litigation with Burst.com almost two decades later.
Audio Highway Listen Up
The world's first company to announce a portable MP3 player and the attendant system for uploading MP3 audio content to a personal computer and then downloading it onto a personal MP3 player was Audio Highway. Under the direction of founder and CEO
Nathan SchulhofNathan M. Schulhof is a technology industry entrepreneur with a career that spans over three decades. Schulhof is listed as the lead inventor on three U.S. patents ,....
, Audio Highway announced its Listen Up player on September 23, 1996, won an Innovations Award for its Listen Up player and its Listen Up Personal Audio System at the
Consumer Electronics ShowThe International Consumer Electronics Show is a major technology-related trade show held each January in the Las Vegas Convention Center, Las Vegas, Nevada, United States. Not open to the public, the Consumer Electronics Association-sponsored show typically hosts previews of products and new...
in January 1997, and began shipping the Listen Up player in the United States in September 1997. The Listen Up player also won a People's Choice Award at the 2nd annual Internet Showcase conference, held Jan. 30, 1998. The device was not mass-produced; only about 25 units were made.
As the lead inventor on three U.S. patents, as well as co-inventor on another U.S. patent, Schulhof is sometimes referred to as "the father of the MP3 player industry."
SaeHan/Eiger MPMan
The world's first mass-produced hardware MP3 player was created in 1997 by
Saehan Information SystemsSaehan is a South Korean corporation established in the beginning of the 1970s. It is now mostly based on textile production. The Saehan Automobile division later became Daewoo Motors...
, which domestically sold its “MPMan” player in April 1998. In mid-1998, the South Korean company licensed the players for North American distribution to Eiger Labs, which rebranded them as the Eiger MPMan F10 and F20. The flash-based players were available in 32 MB (about 6 songs) storage capacity.
Diamond Rio
The
Rio PMP300The Rio PMP300 was a portable consumer MP3 digital audio player , and was produced by Diamond Multimedia. It was introduced September 15, 1998, and it shipped later that year.-Features:...
from
Diamond MultimediaDiamond Multimedia is a company that specializes in many forms of multimedia technology. They have produced graphics cards, motherboards, modems, sound cards and MP3 players, however the company began with the production of the TrackStar, a PC add-on card which emulated Apple II computers...
was introduced in September 1998, a few months after the MPMan, and also featured a 32 MB storage capacity. It was a success during the holiday season, with sales exceeding expectations. Interest and investment in digital music were subsequently spurred from it. Because of the player's notoriety as the target of a major lawsuit, the Rio is erroneously assumed to be the first DAP.
HanGo Personal Jukebox
In 1998,
CompaqCompaq Computer Corporation is a personal computer company founded in 1982. Once the largest supplier of personal computing systems in the world, Compaq existed as an independent corporation until 2002, when it was acquired for US$25 billion by Hewlett-Packard....
developed the first hard drive based DAP using a 2.5" laptop drive. It was licensed to
HanGo ElectronicsRemote Solution Co., Ltd. is an electronics manufacturer located in Gimcheon, South Korea. The company was founded in 1994 as Hango Electronics Co., Ltd. and assumed its current name in 2002....
(now known as Remote Solution), which first sold the PJB-100 (
Personal JukeboxThe Personal Jukebox was the first commercially sold hard disk digital audio player. Introduced late in 1999, it preceded the Apple iPod and similar players. The original design was developed by Compaq Research starting in May 1998...
) in 1999. The player had an initial capacity of 4.8 GB, with an advertised capacity of 1200 songs.
Creative NOMAD Jukebox
In 2000,
CreativeCreative Technology Ltd. is a Singapore-based global company headquartered in Jurong East, Singapore. The principal activities of the company and its subsidiaries consist of the design, manufacture and distribution of digitized sound and video boards, computers and related multimedia, and personal...
released the 6GB hard drive based
Creative NOMAD JukeboxThe NOMAD was a range of digital audio players designed and sold by Creative Technology, and later discontinued in 2004. Subsequent players now fall exclusively under the MuVo and ZEN brands.The NOMAD series consisted of two distinct brands:...
. The name borrowed the
jukeboxA jukebox is a partially automated music-playing device, usually a coin-operated machine, that will play a patron's selection from self-contained media...
metaphor popularised by
Remote Solution and also used by
Archos. Later players in the Creative NOMAD range used
microdriveMicrodrive is a brand name for a miniature, 1-inch hard disk designed to fit in a CompactFlash Type II slot. The release of similar drives by other makers has led to them often being referred to as 'microdrives'...
s rather than laptop drives.
Archos Jukebox
In December 2000, some months after the Creative's
NOMAD Jukebox,
ArchosArchos is a French consumer electronics company that was established in 1988 by Henri Crohas. Archos manufactures portable media players and portable data storage devices. The name is an anagram of Crohas' last name, and it is also Greek for 'master'...
released his
Jukebox 6000 with a 6GB hard drive too.
Apple iPod
On October 23, 2001, Apple Computer unveiled the first generation
iPodiPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...
, a 5 GB hard drive based DAP with a 1.8"
Toshibais a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
hard drive. With the development of a spartan
user interfaceThe user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...
and a smaller form factor, the iPod was initially popular within the
MacintoshThe Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...
community. In July 2002, Apple introduced the second generation update to the iPod. It was compatible with
WindowsMicrosoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
computers through
Musicmatch JukeboxY!Music Musicmatch Jukebox, a remake of the original Musicmatch Jukebox made by Musicmatch, Inc., is an audio player that manages a digital audio library...
. The iPod series, which grew to include
flash memoryFlash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
-based players, is a big name in portable media player market, having sold about 300 million units to date.
Archos Jukebox Multimedia
In 2002,
ArchosArchos is a French consumer electronics company that was established in 1988 by Henri Crohas. Archos manufactures portable media players and portable data storage devices. The name is an anagram of Crohas' last name, and it is also Greek for 'master'...
released the first "portable media player" (PMP), the Archos Jukebox Multimedia with a little 1.5" color screen. Manufacturers have since implemented abilities to view images and play videos into their devices. The next year, Archos released an other multimedia
jukebox, the AV300, with a 3.8" screen and a 20GB hard drive.
Microsoft
In 2004,
MicrosoftMicrosoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
attempted to take advantage of the growing PMP market by launching the
Portable Media CenterPortable Media Center is a defunct hard drive-based portable media player platform developed by Microsoft. Announced at the 2003 Consumer Electronics Show , and released in early 2004, it was originally positioned as a competitor to Apple's iPod.The platform was conceived in line with Microsoft's...
(PMC) platform. It was introduced at the 2004
Consumer Electronics ShowThe International Consumer Electronics Show is a major technology-related trade show held each January in the Las Vegas Convention Center, Las Vegas, Nevada, United States. Not open to the public, the Consumer Electronics Association-sponsored show typically hosts previews of products and new...
with the announcement of the Zen Portable Media Center, which was co-developed by
CreativeCreative Technology Ltd. is a Singapore-based global company headquartered in Jurong East, Singapore. The principal activities of the company and its subsidiaries consist of the design, manufacture and distribution of digitized sound and video boards, computers and related multimedia, and personal...
. The Microsoft
ZuneZune is a digital media brand owned by Microsoft which includes a line of portable media players, a digital media player software for Windows machines, a music subscription service known as a 'Zune Music Pass', music and video streaming for the Xbox 360 via the Zune Software, music, TV and movie...
series would later be based on the Gigabeat S, one of the PMC-implemented players.
Mobile phones
In 2001 MP3 players functionality began to appear in mobile phones. The idea spread across the globe and by 2005 all major handset makers had released musicphones. By 2006, more MP3 players were sold in mobile phones than all stand-alone MP3 players put together. The rapid rise of the media player in phones was quoted by Apple as a primary reason for developing the iPhone. In 2007, the installed base of musicphones passed the 1 billion level.
Types
Digital audio players are generally categorized by storage media:
- Flash-based players: These are non-mechanical solid state
Solid-state electronics are those circuits or devices built entirely from solid materials and in which the electrons, or other charge carriers, are confined entirely within the solid material...
devices that hold digital audio files on internal flash memoryFlash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
or removable flash media called memory cardA memory card or flash card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players, and video game consoles...
s. Due to technological advances in flash memoryFlash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
, these originally low-storage devices are now available commercially ranging up to 64 GB. Because they are solid state and do not have moving parts they require less battery power, are less likely to skip during playback, and may be more resilient to hazards such as dropping or fragmentation than hard disk-based players. There are USB flash driveA flash drive is a data storage device that consists of flash memory with an integrated Universal Serial Bus interface. flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g...
s available that include basic MP3 playback capabilities.
- Hard drive-based players or digital jukeboxes: Devices that read digital audio files from a hard disk drive (HDD). These players have higher capacities ranging up to 500 GB. At typical encoding rates, this means that tens of thousands of songs can be stored on one player. The disadvantages with these units is that a hard drive consumes more power, is larger and heavier and is inherently more fragile than solid-state storage, thus more care is required to not drop or otherwise mishandle these units.
- MP3 CD
An MP3 CD is a Compact Disc that contains digital audio in the MP3 file format. Discs are written in the Yellow Book standard data format , as opposed to the Red Book standard audio format ....
/DVDA DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
players: Portable CD players that can decode and play MP3 audio files stored on CDsThe Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...
. Such players are typically much less expensive than either the hard drive or flash-based players. Also, the blank CD-RA CD-R is a variation of the Compact Disc invented by Philips and Sony. CD-R is a Write Once Read Many optical medium, though the whole disk does not have to be entirely written in the same session....
media is very inexpensive, typically costing less than US$0.15 per disk. In addition, these devices have the bonus of being able to play standard "Red book" audio CDs. A disadvantage is that due to the mechanical nature of these devices, they are even more fragile than the hard drive based players, and thus more susceptible to skipping or other misreads of the file during playback if mishandled. Also, a CD can typically hold only around 700 megabytes of data, thus a large library will require multiple disks to contain. However, some of the more expensive, higher-end units are also capable of reading and playing back files contained on larger capacity DVDA DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
disks as well, including the ability to play back and display video content, such as movies.
- Networked
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
audio players: Players that connect via (WiFi) network to receive and play audio. These types of units typically do not have any local storage of their own and must rely on a server, typically a personal computer also on the same network, to provide the audio files for playback.
- USB host/memory card
A memory card or flash card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players, and video game consoles...
audio players: Players that rely on USB flash drives or other memory cards to read data.
Typical features
PMPs are capable of playing
digital audioDigital audio is sound reproduction using pulse-code modulation and digital signals. Digital audio systems include analog-to-digital conversion , digital-to-analog conversion , digital storage, processing and transmission components...
,
imagesA digital image is a numeric representation of a two-dimensional image. Depending on whether or not the image resolution is fixed, it may be of vector or raster type...
, and
videoDigital video is a type of digital recording system that works by using a digital rather than an analog video signal.The terms camera, video camera, and camcorder are used interchangeably in this article.- History :...
. Usually, a color
liquid crystal displayA liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
(LCD) or
organic light-emitting diodeAn OLED is a light-emitting diode in which the emissive electroluminescent layer is a film of organic compounds which emit light in response to an electric current. This layer of organic semiconductor material is situated between two electrodes...
(OLED) screen is used as a display. Various players include the ability to record video, usually with the aid of optional accessories or cables, and audio, with a built-in
microphoneA microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...
or from a
line-outA line-out is the means by which, in rugby union, the ball is put back into play after it has gone into touch. It is the equivalent of the throw-in in soccer. Rugby league abolished line-outs in 1897...
cable or
FM tunerFM broadcasting is a broadcasting technology pioneered by Edwin Howard Armstrong which uses frequency modulation to provide high-fidelity sound over broadcast radio. The term "FM band" describes the "frequency band in which FM is used for broadcasting"...
. Some players include readers for
memory cardA memory card or flash card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players, and video game consoles...
s, which are advertised to equip players with extra storage or transferring media. In some players, features of a
personal organizerA personal organizer, day planner, personal analog assistant, or personal planner is a small book/binder, designed to be portable, usually containing a diary, calendar, address book, and other sections usually including blank paper. It may also include pages with useful information, such as maps,...
are emulated, or support for games, like the iriver clix (through compatibility of Adobe Flash Lite) or the
PlayStation PortableThe is a handheld game console manufactured and marketed by Sony Corporation Development of the console was announced during E3 2003, and it was unveiled on , 2004, at a Sony press conference before E3 2004...
, is included.
Audio playback
Nearly all players are compatible with the
MP3MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...
audio format, and many others support
Windows Media AudioWindows Media Audio is an audio data compression technology developed by Microsoft. The name can be used to refer to its audio file format or its audio codecs. It is a proprietary technology that forms part of the Windows Media framework. WMA consists of four distinct codecs...
(WMA),
Advanced Audio CodingAdvanced Audio Coding is a standardized, lossy compression and encoding scheme for digital audio. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at similar bit rates....
(AAC) and
WAVWaveform Audio File Format , is a Microsoft and IBM audio file format standard for storing an audio bitstream on PCs...
. Some players are compatible with open-source formats like
Ogg VorbisVorbis is a free software / open source project headed by the Xiph.Org Foundation . The project produces an audio format specification and software implementation for lossy audio compression...
and the Free Lossless Audio Codec (FLAC). Audio files purchased from online stores may include
Digital Rights ManagementDigital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...
(DRM) copy protection, which many modern players support.
Image viewing
The
JPEGIn computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....
format is widely supported by players. Some players, like the
iPod seriesiPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...
, provide compatibility to display additional file formats like
GIFThe Graphics Interchange Format is a bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability....
, PNG, and TIFF, while others are bundled with conversion software.
Video playback
Most newer players support the
MPEG-4MPEG-4 Part 2, MPEG-4 Visual is a video compression technology developed by MPEG. It belongs to the MPEG-4 ISO/IEC standards. It is a discrete cosine transform compression standard, similar to previous standards such as MPEG-1 and MPEG-2...
video format, and many other players are compatible with
Windows Media Video'Windows Media Video is a video compression format for several proprietary codecs developed by Microsoft. The original video format, known as WMV, was originally designed for Internet streaming applications, as a competitor to RealVideo. The other formats, such as WMV Screen and WMV Image, cater...
(WMV) and
AVIAudio Video Interleave , known by its acronym AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. AVI files can contain both audio and video data in a file container that allows synchronous audio-with-video playback...
. Recently, more and more players are enabling compatibility to the
DivXDivX is a brand name of products created by DivX, Inc. , including the DivX Codec which has become popular due to its ability to compress lengthy video segments into small sizes while maintaining relatively high visual quality.There are two DivX codecs; the regular MPEG-4 Part 2 DivX codec and the...
video format and its open-source parallel,
XvidXvid is a video codec library following the MPEG-4 standard, specifically MPEG-4 Part 2 Advanced Simple Profile . It uses ASP features such as b-frames, global and quarter pixel motion compensation, lumi masking, trellis quantization, and H.263, MPEG and custom quantization matrices.Xvid is a...
. Software included with the players may be able to convert video files into a compatible format.
Recording
Many players have a built-in
electret microphoneAn electret microphone is a type of condenser microphone, which eliminates the need for a polarizing power supply by using a permanently charged material....
which allows recording. Usually recording quality is poor, suitable for speech but not music. There are also professional-quality recorders suitable for high-quality music recording with external microphones, at prices starting at a few hundred dollars.
Radio
Some DAPs have FM radio tuners built in. Many also have an option to change the band from the usual 87.5 - 108.0 MHz to the
JapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese band of 76.0 - 90.0 MHz
Common audio formats
Most audio formats use lossy compression, to produce as small as possible a file compatible with the desired sound quality. There is a
trade-offA trade-off is a situation that involves losing one quality or aspect of something in return for gaining another quality or aspect...
between size and sound quality of lossily compressed files; most formats allow different combinations—e.g., MP3 files may use between 32 (worst) and 320 (best) kilobits per second. Different lossy formats may give files of different sizes for the same perceived quality.
The formats supported by a particular DAP depend upon its
firmwareIn electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
; sometimes a firmware update adds more formats. To listen to a file on a player, it must be in a supported format; format conversion on a
computerA computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
is usually possible, but with loss of quality.
MP3MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...
is the dominant format, and is almost universally supported. It is a proprietary format; manufacturers must pay a small royalty to be allowed to support it.
The main proprietary alternative formats are
AACAdvanced Audio Coding is a standardized, lossy compression and encoding scheme for digital audio. Designed to be the successor of the MP3 format, AAC generally achieves better sound quality than MP3 at similar bit rates....
and
WMAWindows Media Audio is an audio data compression technology developed by Microsoft. The name can be used to refer to its audio file format or its audio codecs. It is a proprietary technology that forms part of the Windows Media framework. WMA consists of four distinct codecs...
. Unlike MP3, these formats support
DRMDigital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...
restrictions that are often enforced by files from paid download services.
Free formats, which do not require manufacturers or music distributors to pay a fee, are available, though less widely supported. Examples include
VorbisVorbis is a free software / open source project headed by the Xiph.Org Foundation . The project produces an audio format specification and software implementation for lossy audio compression...
, FLAC, and
SpeexSpeex is a patent-free audio compression format designed for speech and also a free software speech codec that may be used on VoIP applications and podcasts. It is based on the CELP speech coding algorithm. Speex claims to be free of any patent restrictions and is licensed under the revised BSD...
.
Most players can also play uncompressed
PCMPulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...
in a container such as
WAVWaveform Audio File Format , is a Microsoft and IBM audio file format standard for storing an audio bitstream on PCs...
or AIFF.
Software
PMPs are usually packaged with an installation CD/DVD that inserts device drivers (and for some players, software that is capable of seamlessly transferring files between the player and the computer). For recent players, however, these are usually available online via the manufacturers' websites, or natively recognized by the operating system through
Universal Mass StorageThe USB mass storage device class, otherwise known as USB MSC or UMS, is a protocol that allows a Universal Serial Bus device to become accessible to a host computing device, to enable file transfers between the two...
(UMS) or
Media Transfer ProtocolThe Media Transfer Protocol is a devised set of custom extensions to the Picture Transfer Protocol . Whereas PTP was designed for downloading photographs from digital cameras, Media Transfer Protocol supports the transfer of music files on digital audio players and media files on portable media...
(MTP).
Hardware
As with DAPs, PMPs come in either flash or hard disk storage. Storage capacities have reached up to 64 GB for
flash memoryFlash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
based PMPs, first reached by the
3rd Generation iPod TouchThe iPod Touch is a portable media player, personal digital assistant, handheld game console, and Wi-Fi mobile device designed and marketed by Apple Inc. The iPod Touch adds the multi-touch graphical user interface to the iPod line...
, and up to 500 GB for Hard disk drive PMPs, first achieved by the
ArchosArchos is a French consumer electronics company that was established in 1988 by Henri Crohas. Archos manufactures portable media players and portable data storage devices. The name is an anagram of Crohas' last name, and it is also Greek for 'master'...
5 Internet Tablet.
A number of players support memory card slots, including
CompactFlashCompactFlash is a mass storage device format used in portable electronic devices. Most CompactFlash devices contain flash memory in a standardized enclosure. The format was first specified and produced by SanDisk in 1994...
(CF),
Secure DigitalSecure Digital is a non-volatile memory card format developed by the SD Card Association for use in portable devices. The SD technology is used by more than 400 brands across dozens of product categories and more than 8,000 models, and is considered the de-facto industry standard.Secure Digital...
(SD), and
Memory StickMemory Stick is a removable flash memory card format, launched by Sony in October 1998, and is also used in general to describe the whole family of Memory Sticks...
s. They are used to directly transfer content from external devices, and expanding the storage capacity of PMPs.
A standard PMP uses a 5-way
D-padA D-pad is a flat, usually thumb-operated directional control with one button on each point, found on nearly all modern video game console gamepads, game controllers, on the remote control units of some television and DVD players, and smart phones...
to navigate, however there have been many alternatives used. Most notable are the wheel and touch mechanisms seen on players from the
iPodiPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...
and
Sansa seriesThe SanDisk Sansa is a line of 2 to 16 gigabyte flash memory-based digital audio players and portable media players produced by SanDisk.- Sansa Fuze+:...
. Another popular mechanism is the swipe-pad, or 'squircle,' first seen on the
ZuneZune is a digital media brand owned by Microsoft which includes a line of portable media players, a digital media player software for Windows machines, a music subscription service known as a 'Zune Music Pass', music and video streaming for the Xbox 360 via the Zune Software, music, TV and movie...
. Additional buttons are commonly seen for features such as volume control.
Sizes range all the way up to 7 inches. As well, resolutions also vary, going up to WVGA. Most screens come with a color depth of 16-bit, but higher quality video oriented devices may range all the way to 24-bit, otherwise known as Truecolor, with the ability to display 16.7 million distinct colors. Screens commonly have a matte finish but may also come in glossy to increase color intensity and contrast. More and more devices are now also coming with touch screen as a form of primary or alternate input. This can be for convenience and/or aesthetic purposes. Certain devices, on the other hand, have no screen whatsoever, reducing costs at the expense of ease of browsing through the media library.
Some portable media players include a radio receiver, most frequently receiving FM.
Some portable media players have recently added features such as simple camera, built in game emulation (playing Famicon or other game formats from ROM images) and simple text readers and editors.
Operation
Digital samplingIn signal processing, sampling is the reduction of a continuous signal to a discrete signal. A common example is the conversion of a sound wave to a sequence of samples ....
is used to convert an audio wave to a sequence of binary numbers that can be stored in a digital format, such as
MP3MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression...
. Common features of all MP3 players are a memory storage device, such as
flash memoryFlash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
or a miniature hard disk drive, an embedded processor, and an audio
codecA codec is a device or computer program capable of encoding or decoding a digital data stream or signal. The word codec is a portmanteau of "compressor-decompressor" or, more commonly, "coder-decoder"...
microchip to convert the compressed file into an analogue sound signal.
Most DAPs are powered by rechargeable batteries, some of which are not user-replaceable. They have a 3.5 mm stereo jack; music can be listened to with earbuds or
headphonesHeadphones are a pair of small loudspeakers, or less commonly a single speaker, held close to a user's ears and connected to a signal source such as an audio amplifier, radio, CD player or portable Media Player. They are also known as stereophones, headsets or, colloquially, cans. The in-ear...
, or played via an external amplifier and
speakersA loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
. Some devices also contain internal speakers, through which music can be listened to, although these built-in speakers are typically of very low quality.
Nearly all DAPs consists of some kind of display screen, although there are exceptions, such as the
iPod ShuffleThe iPod Shuffle is a digital audio player designed and marketed by Apple Inc. It is the smallest model in Apple's iPod family, and was the first to use flash memory...
, and a set of controls with which the user can browse through the library of music contained in the device, select a track, and play it back. The display, if the unit even has one, can be anything from a simple one or two line monochrome LCD display, similar to what are found on typical pocket calculators, to large, high-resolution, full-color displays capable of displaying photographs or viewing video content on. The controls can range anywhere from the simple buttons as are found on most typical CD players, such as for skipping through tracks or stopping/starting playback to full touch-screen controls, such as that found on the
iPod TouchThe iPod Touch is a portable media player, personal digital assistant, handheld game console, and Wi-Fi mobile device designed and marketed by Apple Inc. The iPod Touch adds the multi-touch graphical user interface to the iPod line...
or the
Zune HDThe Zune HD is a portable media player in the Zune product family released on September 15, 2009 by Microsoft. It is a direct competitor with the Apple iPod and iPhone series of mobile devices. It was initially released in 16 and 32 GB capacities. A 64 GB version was released on April 9, 2010...
. One of the more common methods of control is some type of the
scroll wheelA scroll wheel is a hard plastic or rubbery disc on a computer mouse that is perpendicular to the mouse surface. It is normally located between the left and right mouse buttons.- Functionality :...
with associated buttons. This method of control was first introduced with the Apple iPod and many other manufacturers have created variants of this control scheme for their respective devices.
Content is placed on DAPs typically through a process called "syncing", by connecting the device to a
personal computerA personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
, typically via USB, and running any special software that is often provided with the DAP on a
CD-ROMA CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....
included with the device, or downloaded from the manufacturer's website. Some devices simply appear as an additional disk drive on the host computer, to which music files are simply copied like any other type of file. Other devices, most notably the Apple iPod or Microsoft
ZuneZune is a digital media brand owned by Microsoft which includes a line of portable media players, a digital media player software for Windows machines, a music subscription service known as a 'Zune Music Pass', music and video streaming for the Xbox 360 via the Zune Software, music, TV and movie...
, requires the use of special management software, such as
iTunesiTunes is a media player computer program, used for playing, downloading, and organizing digital music and video files on desktop computers. It can also manage contents on iPod, iPhone, iPod Touch and iPad....
or Zune Software, respectively. The music, or other content such as TV episodes or movies, is added to the software to create a "library". The library is then "synced" to the DAP via the software. The software typically provides options for managing situations when the library is too large to fit on the device being synced to. Such options include allowing manual syncing, in that the user can manually "drag-n-drop" the desired tracks to the device, or allow for the creation of playlists. In addition to the USB connection, some of the more advanced units are now starting to allow syncing through a wireless connection, such as via
WiFiWIFI is a radio station broadcasting a brokered format. Licensed to Florence, New Jersey, USA, the station is currently operated by Florence Broadcasting Partners, LLC.This station was previously owned by Real Life Broadcasting...
or
BluetoothBluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
.
Content can also be obtained and placed on some DAPs, such as the iPod Touch or Zune HD by allowing access to a "store" or "marketplace", most notably the
iTunes StoreThe iTunes Store is a software-based online digital media store operated by Apple. Opening as the iTunes Music Store on April 28, 2003, with over 200,000 items to purchase, it is, as of April 2008, the number-one music vendor in the United States...
or Zune Marketplace, from which content, such as music and video, and even games, can be purchased and downloaded directly to the device.
Controversy
Although these issues are not usually controversial within digital audio players, they are matters of continuing controversy and litigation, including but not limited to content distribution and protection, and
digital rights managementDigital rights management is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale. DRM is any technology that inhibits uses of digital content that...
(DRM).
Lawsuit with RIAA
The
Recording Industry Association of AmericaThe Recording Industry Association of America is a trade organization that represents the recording industry distributors in the United States...
(RIAA) filed a lawsuit in late 1998 against
Diamond MultimediaDiamond Multimedia is a company that specializes in many forms of multimedia technology. They have produced graphics cards, motherboards, modems, sound cards and MP3 players, however the company began with the production of the TrackStar, a PC add-on card which emulated Apple II computers...
for its
RioThe Rio PMP300 was a portable consumer MP3 digital audio player , and was produced by Diamond Multimedia. It was introduced September 15, 1998, and it shipped later that year.-Features:...
players, alleging that the device encouraged copying music illegally. But Diamond won a legal victory on the shoulders of the
Sony Corp. v. Universal City StudiosSony Corp. of America v. Universal City Studios, Inc., 464 U.S. 417 , also known as the "Betamax case", is a decision by the Supreme Court of the United States which ruled that the making of individual copies of complete television shows for purposes of time-shifting does not constitute copyright...
case and DAPs were legally ruled as electronic devices.
Risk of hearing damage
According to SCENIHR, the risk of hearing damage from digital audio players depends on both sound level and listening time. The listening habits of most users are unlikely to cause hearing loss, but some people are putting their hearing at risk, because they set the volume control very high or listen to music at high levels for many hours per day. Such listening habits may result in temporary or permanent hearing loss,
tinnitusTinnitus |ringing]]") is the perception of sound within the human ear in the absence of corresponding external sound.Tinnitus is not a disease, but a symptom that can result from a wide range of underlying causes: abnormally loud sounds in the ear canal for even the briefest period , ear...
, and difficulties understanding speech in noisy environments.
Alternative methods to reduce risk
Much of the risk of hearing loss is largely associated to the fact that many use headphones with the devices, and that they consider them personal devices instead of stereo system components. If a digital audio player is connected via its
TRS connectorA TRS connector is a common family of connector typically used for analog signals including audio. It is cylindrical in shape, typically with three contacts, although sometimes with two or four . It is also called an audio jack, phone jack, phone plug, and jack plug...
to a separate amplification device like a bookshelf stereo or car head-unit, then the output can be via speakers rather than a headphone.
See also
- Comparison of portable media players
The following comparison of portable media players compares general and technical information for notable digital playback devices.- General :- Technical specifications :- Syncing and transfer :- Wifi Connectivity :- Audio formats :...
- Internet radio device
An Internet radio device, also called network music player is a hardware device that is capable of receiving and playing streamed media from either Internet radio stations or a home network.-Background:...
- Media Transfer Protocol
The Media Transfer Protocol is a devised set of custom extensions to the Picture Transfer Protocol . Whereas PTP was designed for downloading photographs from digital cameras, Media Transfer Protocol supports the transfer of music files on digital audio players and media files on portable media...
- MP4 player
- Portable DVD player
Portable DVD Player is the name given to any portable device whose primary function is the playing of DVDs.-History:...
- USB mass storage device class
The USB mass storage device class, otherwise known as USB MSC or UMS, is a protocol that allows a Universal Serial Bus device to become accessible to a host computing device, to enable file transfers between the two...
- USB video recorder
- Walkman Circ
The Walkman Circ is a circular MP3 player about the size of a circular bar of soap. It was released in 2001.- Producer:The Sony Circ Audio Walkman comes from the walkman division of Sony. It comes from a line of MP3 players dependent on advancing nanotechnology.-Colour:The walkman comes in a...
External links
- Collecting MP3 Portables – Part I, Part II and Part III - Richard Menta
Richard Menta is an American journalist, and the publisher of MP3 Newswire. Known for over a decade of commentary that followed the evolution of digital media and intellectual property protection, Menta is also an information security professional. David L...
's three-part article covers the first digital audio players on the market with pictures of each player.