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An artifact is a noticeable difference between an uncompressed signal and a lossily-compressed copy. Lossy encoding can result in very different kind of artifacts/distortions. Sometimes it's not easy to define why the encoding is non-transparent. There are however many typical encoding artifacts.

Common artifacts

  • pre echo: pre-echo consists in a small amount of noise used to appear just before a contrasted sound events (like percussive instruments). The original transients are therefore smeared: "___shhhTak" instead of "____Tak".
Illustrative samples: castanets.wav, castanets2.wav
The phenomenon could sometimes be visualised on a frequency editor:
To listen to the corresponding artifact, click here

  • ringing:

  • warbling:

  • coarseness:

  • stereo collapse:

External links

  • ff123's Audio Artifact Training Page