Difference between revisions of "User talk:Tahnru"

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(Grabbing a copy of the lossy article for major re-write)
 
(first draft, getting a start.)
 
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'''Lossy''' compression is a form of compression that significantly reduce multimedia file size by throwing away information imperceptible to humans.
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'''Lossy'''  
  
Human audio perception is not perfect. Lossy compression takes advantage of this characteristic. By selective discarding, much unnecessary information is thrown away. The amount of information discarded is usually adjustable, giving a compromise between smaller size with less quality and larger size with higher quality.
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In the context of digital audio, Lossy Compression refers to the technique of discarding some audio data from the input file to produce an output file that is similar enough to the original to be usable while reducing the file size beyond the limits of known lossless compression techniques. The information selected for removal is chosen according through various methods ranging from a simple low-pass approach to complex psychoacoustic models.
  
The downside to this is that waveform reconstructed from compressed information will never exactly match the original waveform.
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Benefits of Lossy Encoding:
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Space Savings
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Downsides to Lossy Encoding:
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Generational degradation
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Perceptual non-transparancy due to either insufficient bandwidth, incorrect algorithm, inherent limitation of the format.
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== General Lossy Encoding Techniques ==
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Low-pass filter
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Decrease in resolution for noisy passages
  
 
== Does Lossy Encoding Preserve Surround Information? ==
 
== Does Lossy Encoding Preserve Surround Information? ==

Latest revision as of 22:28, 10 May 2010

Lossy

In the context of digital audio, Lossy Compression refers to the technique of discarding some audio data from the input file to produce an output file that is similar enough to the original to be usable while reducing the file size beyond the limits of known lossless compression techniques. The information selected for removal is chosen according through various methods ranging from a simple low-pass approach to complex psychoacoustic models.

Benefits of Lossy Encoding: Space Savings

Downsides to Lossy Encoding: Generational degradation Perceptual non-transparancy due to either insufficient bandwidth, incorrect algorithm, inherent limitation of the format.

General Lossy Encoding Techniques

Low-pass filter Decrease in resolution for noisy passages

Does Lossy Encoding Preserve Surround Information?

Depending on the encoder and settings, degradation of surround imaging may happen. Use higher bitrate to prevent this from happening. Mid/Side stereo of LAME or AAC does not destroy surround information. Also MPC preserves surround information with standard settings reasonably well. The lower the bitrate, the worse you can expect the surround imaging become.

List of common lossy formats

See Also