[About MP3 Technology]
The MP3 player is the most recent in an evolution of music formats that have helped consumers enjoy their tunes. Records, 8-track tapes, cassette tapes and CDs -- none of these earlier music formats provide the convenience and control that MP3 players deliver. With an MP3 player in hand or pocket, a consumer can create personalized music lists and carry thousands of songs wherever they go.
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­­ All of that stored music and the MP3 player itself fit into a device that, in some cases, weighs less than one ounce. Portability is a large factor in the popularity of the MP3, considering the ease of transportation in comparison to a CD player and CD storage case. In addition, some devices provide additional technology, like video and photo viewing, alarm and calendar functions, and even cell phone and Internet service.­
In this article, you'll learn more about the technology inside MP3 players and the different types of players available. You'll also find out how to get tunes and how you can accessorize your player.
The MP3 File Format
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 the trade-off for the ability 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. (Some CDs support MP3 files.)
Although MP3 is perhaps the most well-known file format, there are other file formats 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
• Ogg Vorbis - A free, open and un-patented music format
• ADPCM - Adaptive Differential Pulse Code Modulation
• ASF - Advanced Streaming Format
• VQF - Vector Quantization Format
• ATRAC - Sony's Adaptive Transform Acoustic Coding 3

In the next section, we'll look at the technology behind the player that allows you to listen to your music.
The Technology
Unlike earlier forms of music players that required moving parts to read encoded data on a tape or CD, MP3 players use solid-state memory. An MP3 player is no more than a data-storage device with an embedded software application that allows users to transfer MP3 files to the player. MP3 players also include utilities for copying music from the radio, CDs, radio or Web sites and the ability to organize and create custom lists of songs in the order you want to hear them. This list of songs is called a playlist.
The MP3 player is the convergence of many technologies. Alone, none of its components are revolutionary, but together they create an unprecedented consumer product.
Specific components may vary, but here are the basic parts of a typical MP3 player:

• Data port
• Memory
• Microprocessor
• Digital signal processor (DSP)
• Display
• Playback controls
• Audio port
• Amplifier
• Power supply

The player plugs into your computer's USB port, FireWire port or parallel port to transfer data. USB-based players transfer data many times faster than those that use the parallel port. The MP3 files are saved in the player's memory.
Memory types include:

• Internal Flash memory
• CompactFlash cards
• SmartMedia cards
• Memory Stick
• Internal microdrive

With the exception of the last one, these are all types of solid-state memory. The advantage to solid-state memory is that there are no moving parts, which means better reliability and no skips in the music. MP3 players that contain tiny hard disk drives can store 10 to 150 times more than Flash memory devices can.
The microprocessor is the brains of the player. It monitors user input through the playback controls, displays information about the current song on the LCD panel and sends directions to the DSP chip that tells it exactly how to process the audio.

In addition to storing music, the MP3 player must play music and allow the user to hear the songs played. To do this, the player:

• Pulls the song from its memory.
• Decompresses the MP3 encoding, through DPS, via an algorithm or formula.
• Runs the decompressed bytes through a digital-to-analog converter into sound waves.
• Amplifies the analog signal, allowing the song to be heard.

All of the portable MP3 players are battery-powered. Most use a rechargeable internal lithium battery and last for approximately 10 to 28 hours on a single charge. Many of the players also have AC adapters so they can be plugged into a normal electrical outlet, and some even offer DC adapters for use in a car.
In the next section, we'll learn about the different types of MP3 players.