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MP3 players
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 the MP3 format's ubiquity), but DAPs often play many additional file formats. Some formats are proprietary, such as Windows Media Audio (WMA), and to a degree, Advanced Audio Coding (AAC) and MP3. Some of these formats also may incorporate restrictive DRM technology, such as Janus and FairPlay, which are often part of certain paid download sites. Other formats are completely patent-free or otherwise open, such as Ogg Vorbis, FLAC, Speex (all part of the Ogg open multimedia project), and Module file formats. There are three main types of digital audio players:Generally speaking, digital audio players are portable and use headphones, although users often connect players to car and home stereos. Some DAPs also include FM radio tuners and/or microphones for voice recording. Many players can encode audio directly to MP3 or other digital audio formats directly from a line in audio signal. Most have semi-permanent rechargeable batteries while others have conventional battery bays for disposable or rechargeable batteries.Apple's iPod devices incorporate a proprietary dock connector that allows them to connect to accessories such as chargers, or active speakers with built-in charging, or even into car players. Accessories that use the dock connector are only compatible with iPods.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.
MP3 Players
The MP3 file format revolutionized music distribution in the late 1990s, when file-swapping services and the first portable MP3 players made their debut. MP3, or MPEG Audio Layer III, is one method for compressing audio files. MPEG is the acronym for Moving Picture Experts Group, a group that has developed compression systems for video data, including that for DVD movies, HDTV broadcasts and digital satellite systems.Using the MP3 compression system reduces the number of bytes in a song, while retaining sound that is near CD-quality. Anytime you compress a song, you will lose some of its quality, which is a trade off for being able to carry more music files in a smaller storage system. A smaller file size also allows the song to be downloaded from the Internet faster.Consider that an average song is about four minutes long. On a CD, that song uses about 40 megabytes (MB), but uses only 4 MB if compressed through the MP3 format. On average, 64 MB of storage space equals an hour of music. A music listener who has an MP3 player with 1 GB (approximately 1,000 MB) of storage space can carry about 240 songs or the equivalent of about 20 CDs. Songs stored on traditional CDs are already decompressed, so it takes more CDs to store the same amount of songs. Now, some CDs support MP3 files.Although MP3 is perhaps the most well known file format, there are various file formats other than MP3 files that can be played on MP3 players. While most MP3 players can support multiple formats, not all players support the same formats. Here are a few of the file formats that can be played on different players: * WMA - Windows Media Audio * WAV - Waveform Audio * MIDI - Music Instrument Digital Interface. * AAC - Advanced Audio Coding (AAC) * Ogg Vorbis - A free, open, and un-patented music format * ADPCM - Adaptive Differential Pulse Code Modulation * ASF - Advanced Streaming Format * VQF - Vector Quantization Format
