Audio files are large, so they are generally compressed to save space. Most compression techniques are lossy, meaning that there is some loss of quality between the original file and the compressed version. Some people claim that the loss is virtually inaudible, but others claim that they can hear a clear difference. Because compressed files are smaller, they are more portable and easier to transfer over the Internet.
Digital audio files can be edited on a computer using such programs as Adobe Audition or Audacity, an open-source alternative. Editing operations can include moving, copying or deleting parts of a file, changing the pitch or tempo and adding effects, such as echo. Editing software can also be used to convert audio files to different formats. You can hear examples of sound effects from the following links:
Digital audio files can also be streamed over the internet. This means that you don’t have to wait until the whole file has been downloaded before starting to play it – as soon as the first section of the file has been downloaded playback can start. Online music services such as Spotify use streaming audio.
Common audio file formats include the following:
.wav: an uncompressed format used on CDs etc. Audio quality is high, but files are very large.
.mp3: the commonest compressed format, used for most downloads and on digital media players.
.aac: a compressed format used mostly on Apple devices. It was designed to be the successor to mp3, but has never really caught on.
.flac: a lossless compressed format that allows exact restoration of the original.