A portable media player (PMP) or digital audio player, (DAP) is a consumer electronics device that is capable of storing and playing digital media such as audio, images, video, documents, etc. the data is typically stored on a hard drive, microdrive, or flash memory. In contrast, analog portable audio players play music from cassette tapes, or records. Often digital audio players are sold as MP3 players, even if they support other file formats.[1] Other types of electronic devices like cellphones, internet tablets, and digital cameras are sometimes referred as PMPs because of their playback capabilities.[2] This article however focuses on portable devices that have the main function of playing media.
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The immediate predecessor in the market place of the digital audio player was the portable CD player and prior to that, the personal stereo.
British scientist Kane Kramer 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.[3] Apple Inc. hired Kramer as a consultant and presented his work as an example of prior art in the field of digital audio players during their litigation with Burst.com almost two decades later.[4]
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 Schulhof, Audio Highway announced its Listen Up player on September 23, 1996,[5] won an Innovations Award for its Listen Up player and its Listen Up Personal Audio System at the Consumer Electronics Show in January 1997,[6] and began shipping the Listen Up player in the United States in September 1997.[7] The Listen Up player also won a People's Choice Award[8] at the 2nd annual Internet Showcase conference, held Jan. 30, 1998. The device was not mass-produced; only about 25 units were made.[9]
As the lead inventor on three U.S. patents,[10][11][12] as well as co-inventor on another U.S. patent,[13] Schulhof is sometimes referred to as "the father of the MP3 player industry."
The world's first mass-produced hardware MP3 player[14] was created in 1997 by Saehan Information Systems, 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.[15] The flash-based players were available in 32 MB (about 6 songs) storage capacity.
The Rio PMP300 from Diamond Multimedia 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.[16] Interest and investment in digital music were subsequently spurred from it.[17] Because of the player's notoriety as the target of a major lawsuit,[18] the Rio is erroneously assumed to be the first DAP.[19]
In 1998, Compaq developed the first hard drive based DAP using a 2.5" laptop drive. It was licensed to HanGo Electronics (now known as Remote Solution), which first sold the PJB-100 (Personal Jukebox) in 1999. The player had an initial capacity of 4.8 GB, with an advertised capacity of 1200 songs.[20]
In 2000, Creative released the 6GB hard drive based Creative NOMAD Jukebox. The name borrowed the jukebox metaphor popularised by Remote Solution, also used by Archos. Later players in the Creative NOMAD range used microdrives rather than laptop drives.
In December 2000, some months after the Creative's NOMAD Jukebox, Archos released his Jukebox 6000 with a 6GB hard drive too.
On October 23, 2001, Apple Computer unveiled the first generation iPod, a 5 GB hard drive based DAP with a 1.8" Toshiba hard drive. With the development of a spartan user interface and a smaller form factor, the iPod was initially popular within the Macintosh community. In July 2002, Apple introduced the second generation update to the iPod. It was compatible with Windows computers through Musicmatch Jukebox.
In 2002, Archos released the first "portable media player" (PMP), the Archos Jukebox Multimedia[21] 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.
In 2004, Microsoft attempted to take advantage of the growing PMP market by launching the Portable Media Center (PMC) platform. It was introduced at the 2004 Consumer Electronics Show with the announcement of the Zen Portable Media Center,[22] which was co-developed by Creative. The Microsoft Zune series would later be based on the Gigabeat S, one of the PMC-implemented players.
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.
Digital audio players are generally categorized by storage media:
PMPs are capable of playing digital audio, images, and video. Usually, a color liquid crystal display (LCD) or organic light-emitting diode (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 microphone or from a line-out cable or FM tuner. Some players include readers for memory cards, which are advertised to equip players with extra storage or transferring media. In some players, features of a personal organizer are emulated, or support for games, like the iriver clix (through compatibility of Adobe Flash Lite) or the PlayStation Portable, is included.
Nearly all players[25] are compatible with the MP3 audio format, and many others support Windows Media Audio (WMA), Advanced Audio Coding (AAC) and WAV. Some players are compatible with open-source formats like Ogg Vorbis and the Free Lossless Audio Codec (FLAC). Audio files purchased from online stores may include Digital Rights Management (DRM) copy protection, which many modern players support.
The JPEG format is widely supported by players. Some players, like the iPod series, provide compatibility to display additional file formats like GIF, PNG, and TIFF, while others are bundled with conversion software.
Most newer players support the MPEG-4 video format, and many other players are compatible with Windows Media Video (WMV) and AVI. Recently, more and more players are enabling compatibility to the DivX video format and its open-source parallel, Xvid. Software included with the players may be able to convert video files into a compatible format.
Many players have a built-in electret microphone 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.
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 Japanese band of 76.0 - 90.0 MHz
Most audio formats use lossy compression, to produce as small as possible a file compatible with the desired sound quality. There is a trade-off 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.[26]
The formats supported by a particular DAP depend upon its firmware; 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 computer is usually possible, but with loss of quality.
MP3 is the dominant format, and is almost universally supported.[27] It is a proprietary format; manufacturers must pay a small royalty to be allowed to support it.[28]
The main proprietary alternative formats are AAC and WMA. Unlike MP3, these formats support DRM 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 Vorbis, FLAC, and Speex.
Most players can also play uncompressed PCM in a container such as WAV or AIFF.
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 Storage (UMS) or Media Transfer Protocol (MTP).
As with DAPs, PMPs come in either flash or hard disk storage. Storage capacities have reached up to 64 GB for flash memory based PMPs, first reached by the 3rd Generation iPod Touch, and up to 1 TB for Hard disk drive PMPs, first achieved by the Archos 5 Internet Tablet.
A number of players support memory card slots, including CompactFlash (CF), Secure Digital (SD), and Memory Sticks. 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-pad to navigate, however there have been many alternatives used. Most notable are the wheel and touch mechanisms seen on players from the iPod and Sansa series. Another popular mechanism is the swipe-pad, or 'squircle,' first seen on the Zune. 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. Newer PMPs have been able to tell time, and even automatically adjust time according to radio reception, and some devices like the 6th-gen iPod Nano even have wristwatch bands available.
Digital sampling is used to convert an audio wave to a sequence of binary numbers that can be stored in a digital format, such as MP3. Common features of all MP3 players are a memory storage device, such as flash memory or a miniature hard disk drive, an embedded processor, and an audio codec 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 headphones, or played via an external amplifier and speakers. 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 Shuffle, 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 Touch or the Zune HD. One of the more common methods of control is some type of the scroll wheel 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 computer, typically via USB, and running any special software that is often provided with the DAP on a CD-ROM 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 Zune, requires the use of special management software, such as iTunes 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 WiFi or Bluetooth.[29]
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 Store or Zune Marketplace, from which content, such as music and video, and even games, can be purchased and downloaded directly to the device.
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 management (DRM).
The Recording Industry Association of America (RIAA) filed a lawsuit in late 1998 against Diamond Multimedia for its Rio players,[18][30] alleging that the device encouraged copying music illegally. But Diamond won a legal victory on the shoulders of the Sony Corp. v. Universal City Studios case and DAPs were legally ruled as electronic devices.[31]
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, tinnitus, and difficulties understanding speech in noisy environments.[32]
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 connector to a separate amplification device like a bookshelf stereo or car head-unit, then the output can be via speakers rather than a headphone.
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