Artifact: Difference between revisions

From Hydrogenaudio Knowledgebase
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* '''[[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".  
* '''[[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'': [[http://www-ccrma.stanford.edu/~bosse/ castanets.wav]], [[http://anonymousriver.hp.infoseek.co.jp/castanets2/index.html castanets2.wav]]
''Illustrative samples'': [[http://www-ccrma.stanford.edu/~bosse/ castanets.wav]], [[http://anonymousriver.hp.infoseek.co.jp/castanets2/index.html castanets2.wav]]
The phenomenon could sometimes be visualised on a frequency editor:
[[Image:Preecho.png]]
To listen to the corresponding artifact, click [[http://audiotests.free.fr/tests/wiki/castanets2.mp3 here]]


* '''ringing''':
* '''ringing''':

Revision as of 21:42, 10 June 2006

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.


Different kind of 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