Audio file format

An audio file format is a file format for storing digital audio data on a computer system. The bit layout of the audio data (excluding metadata) is called the audio coding format and can be uncompressed, or compressed to reduce the file size, often using lossy compression. The data can be a raw bitstream in an audio coding format, but it is usually embedded in a container format or an audio data format with defined storage layer.

Format types

It is important to distinguish between the audio coding format, the container containing the raw audio data, and an audio codec. A codec performs the encoding and decoding of the raw audio data while this encoded data is (usually) stored in a container file. Although most audio file formats support only one type of audio coding data (created with an audio coder), a multimedia container format (as Matroska or AVI) may support multiple types of audio and video data.

There are three major groups of audio file formats:

Digital audio

Digital audio is technology that can be used to record, store, generate, manipulate, and reproduce sound using audio signals that have been encoded in digital form. Following significant advances in digital audio technology during the 1970s, it gradually replaced analog audio technology in many areas of sound production, sound recording (tape systems were replaced with digital recording systems), sound engineering and telecommunications in the 1990s and 2000s.

A microphone converts sound (a singer's voice or the sound of an instrument playing) to an analog electrical signal, then an analog-to-digital converter (ADC)—typically using pulse-code modulation—converts the analog signal into a digital signal. This digital signal can then be recorded, edited and modified using digital audio tools. When the sound engineer wishes to listen to the recording on headphones or loudspeakers (or when a consumer wishes to listen to a digital sound file of a song), a digital-to-analog converter performs the reverse process, converting a digital signal back into an analog signal, which analog circuits amplify and send to a loudspeaker.

AudioFile (magazine)

AudioFile is a print and online magazine whose mission is to review "unabridged and abridged audiobooks, original audio programs, commentary, and dramatizations in the spoken-word format. The focus of reviews is the audio presentation, not the critique of the written material."AudioFile is published six times a year in Portland, Maine.

Launch

The publication was launched in 1992 as a twelve-page black & white newsletter with about 50 critical reviews of audiobooks, focused on new releases. In 1997, it switched to a 36-page color magazine format with about 60 reviews per issue and interviews with authors, readers, and publishers.

Online

In 2000, AudioFile launched an online database of past issues. Current issues were offered online beginning in 2001.

Subscriptions

AudioFile offers three levels of subscriptions: