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User talk:Tahnru - Revision history
2026-04-29T11:25:11Z
Revision history for this page on the wiki
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Tahnru: first draft, getting a start.
2010-05-10T21:28:16Z
<p>first draft, getting a start.</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 21:28, 10 May 2010</td>
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<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''Lossy''' <del style="font-weight: bold; text-decoration: none;">compression is a form of compression that significantly reduce multimedia file size by throwing away information imperceptible to humans.</del></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''Lossy''' </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">Human </del>audio <del style="font-weight: bold; text-decoration: none;">perception is not perfect. </del>Lossy <del style="font-weight: bold; text-decoration: none;">compression takes advantage </del>of <del style="font-weight: bold; text-decoration: none;">this characteristic. By selective </del>discarding<del style="font-weight: bold; text-decoration: none;">, much unnecessary information </del>is <del style="font-weight: bold; text-decoration: none;">thrown away</del>. The <del style="font-weight: bold; text-decoration: none;">amount of </del>information <del style="font-weight: bold; text-decoration: none;">discarded </del>is <del style="font-weight: bold; text-decoration: none;">usually adjustable, giving </del>a <del style="font-weight: bold; text-decoration: none;">compromise between smaller size with less quality and larger size with higher quality</del>.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">In the context of digital </ins>audio<ins style="font-weight: bold; text-decoration: none;">, </ins>Lossy <ins style="font-weight: bold; text-decoration: none;">Compression refers to the technique </ins>of discarding <ins style="font-weight: bold; text-decoration: none;">some audio data from the input file to produce an output file that </ins>is <ins style="font-weight: bold; text-decoration: none;">similar enough to the original to be usable while reducing the file size beyond the limits of known lossless compression techniques</ins>. <ins style="font-weight: bold; text-decoration: none;"> </ins>The information <ins style="font-weight: bold; text-decoration: none;">selected for removal </ins>is <ins style="font-weight: bold; text-decoration: none;">chosen according through various methods ranging from </ins>a <ins style="font-weight: bold; text-decoration: none;">simple low-pass approach to complex psychoacoustic models</ins>.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">The downside </del>to <del style="font-weight: bold; text-decoration: none;">this is that waveform reconstructed from compressed information will never exactly match </del>the <del style="font-weight: bold; text-decoration: none;">original waveform</del>.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Benefits of Lossy Encoding:</ins></div></td></tr>
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<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Downsides </ins>to <ins style="font-weight: bold; text-decoration: none;">Lossy Encoding:</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Generational degradation</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Perceptual non-transparancy due to either insufficient bandwidth, incorrect algorithm, inherent limitation of </ins>the <ins style="font-weight: bold; text-decoration: none;">format</ins>.</div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">== General Lossy Encoding Techniques ==</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Low-pass filter</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Decrease in resolution for noisy passages</ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Does Lossy Encoding Preserve Surround Information? ==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Does Lossy Encoding Preserve Surround Information? ==</div></td></tr>
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Tahnru
https://wiki.hydrogenaudio.org/index.php?title=User_talk:Tahnru&diff=21325&oldid=prev
Tahnru: Grabbing a copy of the lossy article for major re-write
2010-05-10T21:20:51Z
<p>Grabbing a copy of the lossy article for major re-write</p>
<p><b>New page</b></p><div>'''Lossy''' compression is a form of compression that significantly reduce multimedia file size by throwing away information imperceptible to humans.<br />
<br />
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.<br />
<br />
The downside to this is that waveform reconstructed from compressed information will never exactly match the original waveform.<br />
<br />
== Does Lossy Encoding Preserve Surround Information? ==<br />
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 [[Advanced Audio Coding|AAC]] does not destroy surround information. Also [[Musepack|MPC]] preserves surround information with standard settings reasonably well. The lower the [[bitrate]], the worse you can expect the surround imaging become.<br />
<br />
* [http://www.hydrogenaudio.org/forums/index.php?act=ST&f=15&t=4639 More discussion]<br />
<br />
== List of common lossy formats ==<br />
* [[Advanced Audio Coding]] (AAC, also improperly known as [[MP4]] or [[M4A]])<br />
* [[AC3]]<br />
* [[ATRAC3]]<br />
* [[DTS]]<br />
* [[MP2]]<br />
* [[MP3]]<br />
* [[Musepack]] (also known as MPC, formerly known as MPEGplus or MP+)<br />
* (Ogg) [[Vorbis]]<br />
* [[QDesign]]<br />
* [[Speex]] (speech only)<br />
* [[VQF]]<br />
* [[Windows Media Audio]] (WMA)<br />
<br />
== See Also ==<br />
* [[Lossless]]<br />
<br />
<br />
[[Category:Codecs]]</div>
Tahnru