How MP3 players work

Introduction

A digital audio player, more commonly referred to as an MP3 player, is a consumer electronics device that stores, organizes and plays audio files. Some DAPs are also referred to as portable media players as they have image-viewing and/or video-playing support. MP3 players are now regularly built into mobile phones, making them the most common form of digital audio player.

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Operation

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 compressed sound into analogue form that is then played through the speaker jack.

Most DAPs are powered by rechargeable batteries, some of which are not user replaceable. Listening to music stored on DAPs is typically through earphones and stereo systems connected with a 3.5 mm jack.

Types

Digital audio players are generally categorized by storage media:

Common audio formats

MP3 is the dominant format, and is nearly universally supported. The main alternative formats are AAC and WMA. Unlike MP3, these formats support DRM restrictions that are often implemented into files from paid download services. Open source formats, which are completely patent-free, are available - though less widely supported. Examples include Ogg Vorbis, FLAC, and Speex. Most players can also play uncompressed PCM in a container such as WAV or AIFF. Finally, a recent newcomer is MPEG 4, which is quickly starting to receive adoption by several digital audio players.

Controversy

Although these issues aren't 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).

Lawsuit with RIAA

The Recording Industry Association of America (RIAA) filed a lawsuit with Diamond Multimedia for its Rio players,[13] 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.