Editing Vorbis (section)

==Technical details==
{| class="wikitable" style="float: right; margin: 1em 0 1em 1em; width: 20em; clear: right;"
|-
|+ Vorbis nominal bitrate at quality levels for 44.1&nbsp;kHz stereo input. The new libvorbis v1.2 usually compresses better than these values (effective bitrate may vary).
|-
! Quality
!colspan="2"| Nominal bitrate
|-
!
! Official Xiph.Org Foundation Vorbis
! 
|-
| -q-1
| 45&nbsp;kbit/s
| 48&nbsp;kbit/s
|-
| -q0
|colspan="2"| 64&nbsp;kbit/s
|-
| -q1
|colspan="2"| 80&nbsp;kbit/s
|-
| -q2
|colspan="2"| 96&nbsp;kbit/s
|-
| -q3
|colspan="2"| 112&nbsp;kbit/s
|-
| -q4
|colspan="2"| 128&nbsp;kbit/s
|-
| -q5
|colspan="2"| 160&nbsp;kbit/s
|-
| -q6
|colspan="2"| 192&nbsp;kbit/s
|-
| -q7
|colspan="2"| 224&nbsp;kbit/s
|-
| -q8
|colspan="2"| 256&nbsp;kbit/s
|-
| -q9
|colspan="2"| 320&nbsp;kbit/s
|-
| -q10
|colspan="2"| 500&nbsp;kbit/s
|}

===Outline of coder algorithm===
Vorbis I is a forward-adaptive monolithic transform codec based on the [[modified discrete cosine transform]] (MDCT).<ref name="vorbis-mdct">{{cite web |author=Xiph.Org Foundation |publisher=Xiph.Org Foundation |url=http://www.xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-50001.1.2 |title=Vorbis I specification - 1.1.2 Classification |date=2009-06-02 |access-date=2009-09-22}}</ref> Vorbis uses the modified discrete cosine transform for converting sound data from the [[time domain]] to the [[frequency domain]]. The resulting frequency-domain data is broken into [[noise floor]] and residue components, and then [[Quantization (signal processing)|quantized]] and [[entropy coded]] using a [[codebook]]-based [[vector quantization]] algorithm. The decompression algorithm reverses these stages. The noise-floor approach gives Vorbis its characteristic analog noise-like failure mode when the bitrate is too low to encode the audio without perceptible loss. The sound of compression artifacts at low bitrates is similar to [[Reverberation|reverberations]] in a large space.

===Container formats===
{{See also| Container format (digital)}}
Vorbis streams can be encapsulated in other media [[container format (digital)|container format]]s besides Ogg.<ref>{{cite web|url=http://wiki.xiph.org/index.php/Oggless|title=Oggless proposal| publisher = Xiph.Org Foundation}}</ref> A commonly used alternative is [[Matroska]]. It is also used in [[WebM]], a container format based on a subset of Matroska.<ref name= xiph-webm>{{cite web | url = http://www.xiph.org/press/2010/webm/ | title=Xiph.Org announces support for the WebM open media project| publisher = Xiph.Org | access-date = 2010-05-20 |date=2010-05-19}}</ref><ref name=webm-blog>{{cite web |url = http://webmproject.blogspot.com/2010/05/introducing-webm-open-web-media-project.html |title= Introducing WebM, an open web media project |access-date=2010-05-19 |date=2010-05-19}}</ref><ref name=faq>{{cite web | url = http://www.webmproject.org/about/faq/ | work = WebM | title = FAQ | publisher = Google | date = 2010-05-19}}</ref> Vorbis streams can also be encapsulated in an [[Real-time Transport Protocol|RTP]] payload format.<ref>{{cite IETF|rfc=5215 | title=RTP Payload Format for Vorbis Encoded Audio |date=August 2008 |access-date=2010-06-16 | publisher = IETF| last1= Barbato | first1= Luca }}</ref>

===Metadata===
Vorbis [[metadata]], called [[Vorbis comment]]s, supports metadata tags similar to those implemented in the [[ID3]] standard for MP3. The metadata is stored in a vector of [[8-bit clean|byte strings]] of arbitrary length and size. The size of the vector and the size of each string in bytes is limited to 2<sup>32</sup> − 1 (about 4.3 [[1000000000 (number)|billion]], or any positive integer that can be expressed in 32 bits). This vector is stored in the second header packet that begins a Vorbis bitstream.<ref>{{cite web | url=http://www.xiph.org/vorbis/doc/v-comment.html | title=Vorbis Comment Field Documentation | access-date=2007-03-14 | author=Xiph.Org Foundation}}</ref>

The strings are assumed to be encoded as [[UTF-8]]. Music tags are typically implemented as strings of the form "[TAG]=[VALUE]", for instance, "ARTIST=The John Smith Band". The tag names are case-insensitive, thus typing "ARTIST=The John Smith Band" would be the same as "artist=The John Smith Band". Like the current version of ID3, users and encoding software are free to use whichever tags are appropriate for the content. For example, an encoder could use localized tag labels, live music tracks might contain a "Venue=" tag or files could have multiple genre definitions. Most applications also support common de facto standards such as disc number and [[ReplayGain]] information.

===Variants===
'''{{va|aoTuV}}''' is a notable [[Fork (software development)|fork]] which adds support for encoding at lower bitrates.<ref name="hydrogenaudio-recommended-vorbis-encoder">{{cite web|url=https://wiki.hydrogenaud.io/index.php?title=Recommended_Ogg_Vorbis |title=Recommended Ogg Vorbis - Hydrogenaudio Knowledgebase|access-date=2022-06-30}}</ref> aoTuV's changes were intended to be merged into the reference encoder periodically, but that only happened once in libvorbis 1.1,<ref name="libvorbis-aotuv-merge-changelog">{{cite web|url=https://gitlab.xiph.org/xiph/vorbis/-/blob/84c023699cdf023a32fa4ded32019f194afcdad0/CHANGES#L163-173 |title=libvorbis 1.1 changelog |date=2004-09-22|access-date=2022-06-30}}</ref> due to future merges being a "task that requires uninterrupted time, something I [<nowiki/>[[Chris Montgomery]]] don't have a lot of."<ref name="xiph-monthly-meeting-2007-02">{{cite web|url=https://people.xiph.org/~giles/2007/200702_meeting.txt |title=Xiph.Org Monthly Meeting, 2007/02|date=2007-02-07|archive-url=https://web.archive.org/web/20080930165436/https://people.xiph.org/~giles/2007/200702_meeting.txt |access-date=2022-06-30|archive-date=2008-09-30 }}</ref>