How It Works: Hardware MP3 Players

Hardware MP3 player: a device that stores, decodes, and plays digital audio files without requiring a PC.

The digital music revolution has freed your favorite songs from the tyranny of a physical form. Virtually identical digital copies, in formats such as MP3 or WMA, allow you to listen to the same song over and over without fear of wearing out a cassette or scratching a CD.

But the idea of digital music isn't nearly as interesting if you can listen to it only on your computer. That's the beauty of MP3: Not only can you transfer these small files but you can store them easily on inexpensive portable playback devices. All you need is a player to transfer your music files to. You can now find a ton of portable players and components for your stereo that set the music free from your PC.

Here are the vital statistics:

• Many hardware MP3 players use a digital signal processor (or DSP) to handle the tasks of transferring and decoding MP3 files.
• In addition to the traditional portable players, manufacturers now produce MP3-capable stereo components, car stereos, and even digital cameras and mobile phones that can play MP3 files.
• You can expect the next generation of players to store more music, have faster processors, and support more music file formats.

A hardware MP3 player is a stripped-down, application-specific computing device, with enough power and the specific components needed to store, organize, and play digital music files, as well as display information about them. The player itself behaves as an application would, managing the digital music files you've created and downloaded to the player beforehand.

The heart of any MP3 playback device is its digital signal processor. The DSP handles data transfers, controls the device's interface, and decodes the file for playback. The DSP does just a few things but does them quickly, and uses little power in the process (an especially beneficial trait for portable players).

The process begins when you create or download a digital music file using your PC. When you create a file in the MP3 format (or in the competing WMA and AAC formats), the software that creates the file tosses out bits of data to make the file smaller, a process called lossy compression. (For more on this process, see our companion article, "How It Works: MP3.")

Size Is Everything

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