MP3

See also: Compression | Audio Formats

Shortform: MPEG1-Layer3

An audio format that allows audio files to be compressed to approximately 1/12 of their original size with little noticable quality difference. This format is lossy, meaning some audio data is discarded, removing sounds that cannot be heard or are barely heard by human ears.

This format is the most popular for encoding and sharing music on file sharing networks such as Napster and WinMX. It was created by the Fraunhofer Institute of Erlangen, Germany. This format is several years old and a new and improved version, MP3Pro, was created by the same company. Other formats of similar quality and low size are available that do not have trademark and patent issues such as Ogg Vorbis.

Contents

Playing MP3 files

See: Audio-Video Software (Almost all media players have MP3 playing capability.)

Creating MP3 files

A variety of Mp3 encoding tools exist but three popular ones are included below:

  • Blade – free and open
  • LAME – free and open
  • XING – commercial

XING is the fastest of the three, but is also the lowest quality.

What bitrate do I use for encoding?
Bitrate, or kilobits per second transfer, is a measure of the ballance of file size versus quality. While MP3 is several years old and better, smaller versions have appeared, MP3 is still the standard on some portable audio players and file sharing systems.
Note: it is strongly recommended that you enable “Variable” encoding when “ripping,” or converting files, to MP3. See: Variable Bitrate Compression
  • 32 – low quality voice, similar to an answering machine – good for voicemail-over-email
  • 56 – higher quality voice, good for books-on-tape
  • 96 – low quality music – good for previewing copies of music or with bad speakers. Good for recording radio broadcasts.
  • 128 – medium quality music – for backing up your less-heard Compact Disks
  • 160 – medium-high quality music – for backing up your other CDs
  • 192 – high quality – for oft-listened to CDs
  • 256 – audiophile’s preferred – very near CD-quality
Space saved and quality
A normal compact disk with 16 bit, 44 kilohertz audio 3 minutes long takes up aproximately 36 megabytes. This file, at a 128 bitrate, can be compressed into a 3 megabyte file, suitable for transfer over the Internet and streaming over broadband connections. It could also fit 12 full-length CDs could fit on one CD.
Mono: Voice recordings can be saved at 56 kilobits per second or lower and in mono (one speaker channel), making the file size even smaller. Try saving your audio files at varying rates to find the best quality to size ratio.

Cutting MP3 files

Often, for personal music players, to break a long file into tracks, or to remove unneeded sections of an MP3 file, cutting the file without the hassle of reencoding is necessary.

Related topics

Links/Software

  • Open Directory Project – Long list of MP3-related software, especially mp3Trim – a free program to cut MP3s without re-encoding them (approx 7 meg limit).
  • MP3 filter for file sharing networks to find corrupted MP3 files both on your computer and remotely before they are downloaded.
  • [1] – an easy-to-use encoder for Windows that uses the LAME encoding tool, considered by many to be the best MP3 player available. Free. Also encodeds Ogg Vorbis.
  • Fraunhofer – MP3’s original creator’s history, a German company, who now licenses the use of what remains the most popular MP3 codec. (LAME’s site distributes its source code only – no binaries.)

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