Difference between revisions of "Lossless and lossy"

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'''Lossless''' is a way of compressing data which is fully reversible -- e.g., does not throw away data. A losslessly compressed file can be used to create an exact copy of the source file.
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'''Lossless''' is a way of compressing data which is fully reversible -- e.g., does not "throw away" data. A losslessly compressed file can be used to create an exact copy of the source file.
  
 
'''Lossy''' is the opposite of lossless. A certain amount of data is discarded; how much is usually dependent upon a quality or bitrate setting of the codec.  This makes the file (or stream) much smaller that lossless compression, but reduces the [[quality]].  It is impossible to [[transcode]] from one lossy format to another without further degrading quality.
 
'''Lossy''' is the opposite of lossless. A certain amount of data is discarded; how much is usually dependent upon a quality or bitrate setting of the codec.  This makes the file (or stream) much smaller that lossless compression, but reduces the [[quality]].  It is impossible to [[transcode]] from one lossy format to another without further degrading quality.
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* [[WAVE]] (WAVE is technically a container format, but usually contains lossless PCM audio.)
 
* [[WAVE]] (WAVE is technically a container format, but usually contains lossless PCM audio.)
 
* [[FLAC]]
 
* [[FLAC]]
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* [[WAVPACK]]
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* [[HuffYUV]] video codec
  
 
==Lossy Codecs==
 
==Lossy Codecs==
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* [[AC3]]
 
* [[AC3]]
 
* [[WMA]]
 
* [[WMA]]
* [[Speex]]
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* [[Speex]]  
* All [[codecs|video codecs]]
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* Most [[codecs|video codecs]]  
 
 
  
 
[[Category:Glossary]]
 
[[Category:Glossary]]

Revision as of 07:56, 30 October 2009

Lossless is a way of compressing data which is fully reversible -- e.g., does not "throw away" data. A losslessly compressed file can be used to create an exact copy of the source file.

Lossy is the opposite of lossless. A certain amount of data is discarded; how much is usually dependent upon a quality or bitrate setting of the codec. This makes the file (or stream) much smaller that lossless compression, but reduces the quality. It is impossible to transcode from one lossy format to another without further degrading quality.

Lossless Codecs

  • WAVE (WAVE is technically a container format, but usually contains lossless PCM audio.)
  • FLAC
  • WAVPACK
  • HuffYUV video codec

Lossy Codecs