Exactly what is an MP3?

MP3 stands for MPEG-1 Audio Layer 3. It is the most recognized digital file format. Almost everyone associates MP3 with music, and this recognition factor is due in large part to the music industry's well-publicized legal battle against MP3 distribution. Even though there is a strong association between music and MP3, many people have no idea what MP3 actually is or that it can also file audio books.

Of all the Mp3 players available today, probably the most widely recognized is Apple's iPod.

MP3 is a compression algorithm that reduces the size of audio files considerably. Before the development of audio compression, trading audio files was impractical because of their size. Audio data in the form of stereo CD recordings takes a tremendous amount of hard drive space. Thanks to MP3, audio files could be compressed to about 1/10 of their original size while still retaining good audio quality. This allowed people to upload and download music and books on the Internet.

Today, the music and publising industry has embraced MP3 to some extent, and Internet web sites such as Apple's iTunes allow people to download muic and audio books for a small fee.

What Does MP3 Do?

Typical audio CDs are recorded at 44,100 Hz and 16 bits. This means that 44,100 audio samples are recorded each second and each sample is 16 bits. This is a constant data stream which is equivalent to about 10 MB per minute of stereo audio.

As stated above, MP3 is a compression algorithm. MP3 works by throwing away some of the data, in particular, frequencies which are beyond human hearing. Although this reduces the sound quality, for many people the difference is not noticeable. Sound quality can be improved by encoding the audio at higher bit rates, but this results in larger files.

What are the advantages of MP3?

The big advantage of MP3, of course, is the compact file size. Audio files which are encoded at 128 kb per second are approximately 1/10 the size of the original audio file. In addition to permitting the online distribution of music and audio books, the small size of MP3 files has also spawned the MP3 player market. MP3 players are compact devices, sometimes no bigger than a cigarette lighter, that can hold hundreds of songs.

How do they work?

The process of applying an MP3 algorithm to an audio file is called encoding. In order for the file to playback, the file must first be decoded. For this reason, audio players need a codec (enCOder / DECoder) to play MP3 files. These codecs are included in virtually every portable audio player.

MP3 players are currently one of the hottest consumer items.

MP3 is not the only audio player available. There are many other formats for compressing audio. Support for these alternative formats is not universal, so when shopping for a portable audio player, one of the big considerations is the type of files it can handle.

The second most popular format after MP3 is Windows Media Audio or WMA. This is a Microsoft format that claims to offer higher audio quality at lower bit rates. Lower bit rates translate into smaller file sizes, one of the reasons for the popularity of WMA.

Apple iPod portable music players support the Advance Audio Coding - AAC format. AAC allows up to 48 audio channels and handles higher frequencies better than MP3. The result is better quality sound with smaller files. No wonder iPods are becoming so popular.

Another format that is growing in popularity is Ogg Vorbis. This is an open-source codec that carries no licensing fees and has a sound quality equal to or better than MP3.

For those concerned with audio purity, many players also support uncompressed audio files (WAV). However, at 10 MB per minute, very few WAV files can be stored on the typical portable audio player.