Portable media player

A portable media player (PMP) or digital audio player (DAP) is a portable consumer electronics device capable of storing and playing digital media such as audio, images, and video files.^[1]^[2] The data is typically stored on a compact disc (CD), Digital Versatile Disc (DVD), Blu-ray Disc (BD), flash memory, microdrive, SD cards or hard drive; most earlier PMPs used physical media, but modern players mostly use flash memory. In contrast, analogue portable audio players play music from non-digital media that use analogue media, such as cassette tapes or vinyl records.

Not to be confused with Digital media player.

Digital audio players (DAP) were often marketed as MP3 players even if they also supported other file formats and media types.^[3]^[4] The PMP term was introduced later for devices that had additional capabilities such as video playback. Generally speaking, they are portable, employing internal or replaceable batteries, equipped with a 3.5 mm headphone jack which can be used for headphones or to connect to a boombox, shelf stereo system, or connect to car audio and home stereos wired or via a wireless connection such as Bluetooth. Some players also include radio tuners, voice recording and other features.

DAPs appeared in the late 1990s following the creation of the MP3 codec in Germany. MP3-playing devices were mostly pioneered by South Korean startups, who by 2002 would control the majority of global sales.^[5] However the industry would eventually be defined by the popular Apple iPod.^[6] In 2006, 20% of Americans owned a PMP, a figure strongly driven by the young; more than half (54%) of American teens owned one, as did 30% of young adults aged 18 to 34.^[7] In 2007, 210 million PMPs were sold worldwide, worth US$19.5 billion.^[8] In 2008, video-enabled players would overtake audio-only players.^[9] Increasing sales of smartphones and tablet computers have led to a decline in sales of PMPs,^[10]^[11] leading to most devices being phased out, such as the iPod Touch on May 10, 2022, though certain flagship devices like the Sony Walkman are still in production. Portable DVD and BD players are still manufactured.^[12]

Flash-based players: These are non-mechanical devices that hold digital audio files on internal flash memory, removable flash memory cards or a USB flash drive. Due to technological advances in flash memory, these originally low-capacity storage devices are now available commercially ranging up to 128 GB. Because they are solid state and do not have moving parts they require less battery power, will not skip during playback, and may be more resilient to hazards such as mechanical shock or fragmentation than hard disk-based players.

solid state

Hard drive-based players: Devices that read digital audio files from a . These players have higher capacities as of 2010 ranging up to 500 GB.^[13] 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.

hard disk drive

MP3 CD/DVD players: Portable CD players that can decode and play . Such players were typically a less expensive alternative than either the hard drive or flash-based players when the first units of these were released. The blank CD-R media they use is inexpensive. These devices have the feature of being able to play standard audio CDs. A disadvantage is that due to the low rotational disk speed of these devices, they are even more susceptible to skipping or other misreads if they are subjected to acceleration (shaking) during playback. Since a CD can typically hold only around 700 megabytes of data, a large library will require multiple disks to contain. However, some higher-end units are also capable of reading and playing back files stored on larger-capacity DVD; some also have the ability to play video content, such as movies. An additional consideration can be the relatively large width of these devices since they have to be able to fit a CD.

MP3 audio files stored on CDs

Networked audio players: Players that connect via (Wi-Fi) 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.

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Digital audio players are generally categorised by storage media:

Some MP3 players can encode directly to MP3 or other digital audio formats directly from a line-level audio signal (radio, voice, etc.). Devices such as CD players can be connected to the MP3 player (using the USB port) in order to directly play music from the memory of the player without the use of a computer.

Modular MP3 keydrive players are composed of two detachable parts: the head (or reader/writer) and the body (the memory). They can be independently obtained and upgradable (one can change the head or the body; i.e. to add more memory).

Devices that play . Often, they can be used to play both audio CDs and homemade data CDs containing MP3 or other digital audio files.

CDs

Pocket devices. These are solid-state devices that hold digital audio files on internal or external media, such as . These are generally low-storage devices, typically ranging from 128MB to 1GB, which can often be extended with additional memory. As they are solid state and do not have moving parts, they can be very resilient. Such players may be integrated into USB flash drives.

memory cards

Devices that read digital audio files from a . These players have higher capacities, ranging from 1.5 to 100 GB, 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. Apple's popular iPod player is the best-known example.

hard drive

Uncompressed audio: Most players can also play uncompressed PCM in a container such as WAV or AIFF.

PCM

formats: These formats maintain the Hi-fi quality of every song or disc. These are the ones used by CDs, many people recommend the use of lossless audio formats to preserve the CD quality in audio files on a desktop. Some of them are: Apple Lossless (proprietary format) and FLAC (Royalties free) are increasingly popular formats for lossless compression, which maintain the Hi-fi quality.

Lossless 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-off between size and sound quality of lossily compressed files; most formats allow different combinations—e.g., MP3 files may use between 32 (worst), 128 (reasonable) and 320 (best) kilobits per second.^[66]

Lossy compression

There are three categories of audio formats:

There are also royalty free lossy formats like Vorbis for general music and Speex and Opus used for voice recordings. When "ripping" music from CDs, many people recommend the use of lossless audio formats to preserve the CD quality in audio files on a desktop, and to transcode the music to lossy compression formats when they are copied to a portable player.^[67] The formats supported by a particular audio player depends upon its firmware; sometimes a firmware update adds more formats. MP3 and AAC are dominant formats,^[67] and are almost universally supported.^[68]

Storage

Part II and Part III – Richard Menta's three-part article covers the first digital audio players on the market with pictures of each player.