Artifact: Difference between revisions

From Hydrogenaudio Knowledgebase
m (formatting)
 
(10 intermediate revisions by 3 users not shown)
Line 1: Line 1:
An '''artifact''' is a noticeable difference between an uncompressed signal and a [[lossy|lossily]]-compressed copy.
An '''artifact''' is a noticeable difference between an uncompressed signal and a [[lossy|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.
[[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'': [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''':
* '''warbling''':
* '''coarseness''':
* '''stereo collapse''':




===External links===
===External links===
*[http://ff123.net/training/training.html ff123's Audio Artifact Training Page]
*<s>ff123's Audio Artifact Training Page</s>
 


{{stub}}
{{stub}}
[[Category:Listening Tests]]

Latest revision as of 06:26, 13 September 2013

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