Hydrogenaudio Knowledgebase - User contributions [en]

Noise normalization

2005-09-23T15:59:47Z

Nowhere man:

'''Noise normalization''' is special type of coding technique (somewhat comparable [[PNS]] used in [[AAC]], but not the same) used by [[Ogg Vorbis]] psychoacoustics model to '''compensate''' for loss of energy in certain frquency bands due to quantization (usually because of a low [[SNR]]). The algorithm uses an apsort function to determine where the energy lost in each frequency band is the greatest and compensates the band with the greatest energy lost by '''reviving the residue''' ''(see [http://trac.xiph.org/cgi-bin/trac.cgi/file/trunk/vorbis/lib/psy.c psy.c] in source)''. This is main cause of most ''metallic artifacts'' in MP3. It is '''one factor''' that gives Vorbis it's ''noise-like'' sound characteristics when the bitrate is too low to encode without susceptible artifacts. In the reference encoder it's used on all quality values less than 7.

Vorbis comment

2005-09-21T22:49:46Z

Nowhere man: bad URI

The tagging format normally used by [[Ogg Vorbis]] and [[FLAC]] is called "vorbis comment". It is a relatively simple format that allows the user to specify arbitrary name/value pairs, using UTF-8 as the character encoding.

To avoid incompatibilities between tags some standard fieldnames are suggested by the vorbis comment specification (TITLE, VERSION, ALBUM, ARTIST, TRACKNUMBER, etc.). The full vorbis comment specification can be found at http://www.xiph.org/vorbis/doc/v-comment.html.

Replay Gain

2005-09-21T22:41:21Z

Nowhere man: /* Implementations */

=Introduction=
Replaygain calculates the average perceived loudness of either a track (track gain) or an album (album gain) and uses this information to properly adjust the volume of tracks, that are mastered at different volume levels, during playback. This will make sure that you will have a similar volume levels on all of your tracks or albums without losing any dynamic range of your music. In the case of Album Gain, it will even make sure that more quiet tracks of an album will sound more quiet and tracks that where meant to be louder, louder.
It shouldn't be confused with algorithms that adjust playback volume dynamically within a single track.

=Implementations=
There are different replaygain implementations, each with its own uses and strength. Most of them use [[metadata]] to indicate the level of the volume change (Volume is adjusted on playback; needs player/decoder support) others modify the Audio Data itself. Generally it is recommended to use an implementation which uses [[metadata]] and does not touch the audio itself.

Replaygain has significant advantages over normalizing. It allows the peak loudness of a song to be consistent over an entire collection of audio, much like normalizing (this is called 'Track Gain'). However, it also allows the peak loudness of an album to be consistent over a entire music collection, allowing the dynamics of album to remain (This is called 'Album Gain'). In a [[metadata]] based solution, information on both types of replaygain can be stored, and the desired playback effect can be switched back and forth in the appropriate player. However, if the audio is permanently modified, only one type of replaygain can be chosen.

==MP3Gain==
[http://mp3gain.sourceforge.net/ MP3Gain]

Format: [[MP3]]

Method: Audio or Meta

* In Meta mode, the tags are written in [[APEv2]] tags.
* In Audio Data Mode, the gain is applied to each frame's gain byte, and the process can be perfectly reverted.

Limitations: Limited to 1.5db steps in Audio Data mode

==LAME==
[http://lame.sourceforge.net/ LAME]

Format: [[MP3]]

Method: Header ([http://gabriel.mp3-tech.org/mp3infotag.html mp3infotag])

Notes: Added during encoding; not supported by any player yet; Track Gain only

==Replaygain==
[http://rarewares.org/mpc.html MPC replaygain]

Format: MPC

Method: Header (similar to Meta data method. See "notes".)

Notes: Replaygain values are stored in the header and replaygain is part of the Musepack specifications; therefore any Musepack decoder that does not support replaygain can be considered broken.

==Vorbisgain==
[http://www.sjeng.org/vorbisgain.html Vorbisgain]

Format: [[Ogg Vorbis]]

Method: Meta (in [[Vorbis comment]])

==FLAC/metaflac==
[http://flac.sf.net FLAC]

Format: [[FLAC]]

Method: Meta (in [[Vorbis comment]])

==foobar2000 replaygain scanner==
[http://foobar2000.org Foobar2000]

Format:
* [[MP3]]: Values written to [[APEv2]] or [[ID3v2]] tags.
* [[MPC]]: Values written to header as decribed under "replaygain".
* [[Ogg Vorbis]]: In [[Vorbis comment]].
* [[AAC]]: Values written to [[APEv2]] tags.
* [[MP4]]: Uses its own itunes-compatible tagging system (though itunes does not support replaygain).
* [[FLAC]]: In [[Vorbis comment]].
* [[APE]]: Values written to [[APEv2]] tags.
* [[WAV]]: Optionally saved into [[APEv2]] tags; otherwise the foobar2000 database is used.
* Modules ([[MOD]] etc.): Optionally saved into [[APEv2]] tags; otherwise the foobar2000 database is used.

You can also choose to only have the replaygain values saved in the foobar2000 database and leave the files untouched.

All other formats are supported but the replaygain values are saved to the foobar2000 database.

==Wavegain==
[http://www.rarewares.org/files/others/wavegain.zip Wavegain]

Format: PCM Wave

Method: Audio

Limitations: Irreversible

=Players support=
Replaygain being present in the specs of flac, mpc and ape formats, any player that support those formats usually support replaygain.

The situation with MP3 is rather different, as it was not part of the mp3 specs. The APEv2 tags metadata implementation is somewhat becoming the de-facto standard.

==Windows==
* [[Foobar2000]] supports replaygain in all possible aspects. (it can also calculate replaygain)
* [[Winamp]]. MP3 replaygain support with adequate plugins (e.g. [http://www3.cypress.ne.jp/otachan/in_mpg123.html Otachan's in_mpg123] - if your japanese is not that good, you can find details [http://www.hydrogenaudio.org/forums/index.php?showtopic=18530 in this thread])
* [[XMPlay]] recently implemented replaygain

and probably others.

==Linux==
* [[XMMS]]. Reads replaygain from FLAC, MPC, ogg ..
For mp3, use the CVS version of the [http://xmms-mad.sourceforge.net/ xmms-mad] mp3 plugin (it's not yet released as binaries, furthermore not available in distribs' versions for now. Meanwhile binaries are available there : [http://perso.crans.org/~krempp/xmms-mad/ custom binaries])

and possibly others, since [http://developer.kde.org/~wheeler/taglib.html TagLib] added support for APEv2 tags in mp3 files, players using this library (like [[amarok]] and [[JuK]]) might support that kind of replaygain tags in the near future.

==Portable devices==
Current development builds of [http://www.rockbox.org/ Rockbox] for the iRiver H100 series players support replaygain for some encoder formats. This is a rapidly evolving feature. There are no other portable players known to support replaygain.

The iPod features ''Soundcheck'', which seems to produce roughly the same normalization gains as replaygain, but doesnt provide an Album Gain.

=Additional reading=
* [http://replaygain.hydrogenaudio.org Original replaygain website] (this hasn't been updated since 2001, and everything there is outdated except for the description of the algorithm - but know that the 83dB SPL reference has since then be changed to 89 dB SPL ..)
* audio engineer Bob Katz's many interesting pages (e.g. [http://www.digido.com/portal/pmodule_id=11/pmdmode=fullscreen/pageadder_page_id=93/ this one]) is the best source to understand why replaygain is useful, and understand all that digital audio stuff. This actually was in part responsible for the design of replaygain by David Robinson in the first place, IIRC.

Replay Gain

2005-09-21T22:41:00Z

Nowhere man: /* Implementations */

=Introduction=
Replaygain calculates the average perceived loudness of either a track (track gain) or an album (album gain) and uses this information to properly adjust the volume of tracks, that are mastered at different volume levels, during playback. This will make sure that you will have a similar volume levels on all of your tracks or albums without losing any dynamic range of your music. In the case of Album Gain, it will even make sure that more quiet tracks of an album will sound more quiet and tracks that where meant to be louder, louder.
It shouldn't be confused with algorithms that adjust playback volume dynamically within a single track.

=Implementations=
There are different replaygain implementations, each with its own uses and strength. Most of them use [[meta data]] to indicate the level of the volume change (Volume is adjusted on playback; needs player/decoder support) others modify the Audio Data itself. Generally it is recommended to use an implementation which uses [[meta data]] and does not touch the audio itself.

Replaygain has significant advantages over normalizing. It allows the peak loudness of a song to be consistent over an entire collection of audio, much like normalizing (this is called 'Track Gain'). However, it also allows the peak loudness of an album to be consistent over a entire music collection, allowing the dynamics of album to remain (This is called 'Album Gain'). In a [[metadata]] based solution, information on both types of replaygain can be stored, and the desired playback effect can be switched back and forth in the appropriate player. However, if the audio is permanently modified, only one type of replaygain can be chosen.

==MP3Gain==
[http://mp3gain.sourceforge.net/ MP3Gain]

Format: [[MP3]]

Method: Audio or Meta

* In Meta mode, the tags are written in [[APEv2]] tags.
* In Audio Data Mode, the gain is applied to each frame's gain byte, and the process can be perfectly reverted.

Limitations: Limited to 1.5db steps in Audio Data mode

==LAME==
[http://lame.sourceforge.net/ LAME]

Format: [[MP3]]

Method: Header ([http://gabriel.mp3-tech.org/mp3infotag.html mp3infotag])

Notes: Added during encoding; not supported by any player yet; Track Gain only

==Replaygain==
[http://rarewares.org/mpc.html MPC replaygain]

Format: MPC

Method: Header (similar to Meta data method. See "notes".)

Notes: Replaygain values are stored in the header and replaygain is part of the Musepack specifications; therefore any Musepack decoder that does not support replaygain can be considered broken.

==Vorbisgain==
[http://www.sjeng.org/vorbisgain.html Vorbisgain]

Format: [[Ogg Vorbis]]

Method: Meta (in [[Vorbis comment]])

==FLAC/metaflac==
[http://flac.sf.net FLAC]

Format: [[FLAC]]

Method: Meta (in [[Vorbis comment]])

==foobar2000 replaygain scanner==
[http://foobar2000.org Foobar2000]

Format:
* [[MP3]]: Values written to [[APEv2]] or [[ID3v2]] tags.
* [[MPC]]: Values written to header as decribed under "replaygain".
* [[Ogg Vorbis]]: In [[Vorbis comment]].
* [[AAC]]: Values written to [[APEv2]] tags.
* [[MP4]]: Uses its own itunes-compatible tagging system (though itunes does not support replaygain).
* [[FLAC]]: In [[Vorbis comment]].
* [[APE]]: Values written to [[APEv2]] tags.
* [[WAV]]: Optionally saved into [[APEv2]] tags; otherwise the foobar2000 database is used.
* Modules ([[MOD]] etc.): Optionally saved into [[APEv2]] tags; otherwise the foobar2000 database is used.

You can also choose to only have the replaygain values saved in the foobar2000 database and leave the files untouched.

All other formats are supported but the replaygain values are saved to the foobar2000 database.

==Wavegain==
[http://www.rarewares.org/files/others/wavegain.zip Wavegain]

Format: PCM Wave

Method: Audio

Limitations: Irreversible

=Players support=
Replaygain being present in the specs of flac, mpc and ape formats, any player that support those formats usually support replaygain.

The situation with MP3 is rather different, as it was not part of the mp3 specs. The APEv2 tags metadata implementation is somewhat becoming the de-facto standard.

==Windows==
* [[Foobar2000]] supports replaygain in all possible aspects. (it can also calculate replaygain)
* [[Winamp]]. MP3 replaygain support with adequate plugins (e.g. [http://www3.cypress.ne.jp/otachan/in_mpg123.html Otachan's in_mpg123] - if your japanese is not that good, you can find details [http://www.hydrogenaudio.org/forums/index.php?showtopic=18530 in this thread])
* [[XMPlay]] recently implemented replaygain

and probably others.

==Linux==
* [[XMMS]]. Reads replaygain from FLAC, MPC, ogg ..
For mp3, use the CVS version of the [http://xmms-mad.sourceforge.net/ xmms-mad] mp3 plugin (it's not yet released as binaries, furthermore not available in distribs' versions for now. Meanwhile binaries are available there : [http://perso.crans.org/~krempp/xmms-mad/ custom binaries])

and possibly others, since [http://developer.kde.org/~wheeler/taglib.html TagLib] added support for APEv2 tags in mp3 files, players using this library (like [[amarok]] and [[JuK]]) might support that kind of replaygain tags in the near future.

==Portable devices==
Current development builds of [http://www.rockbox.org/ Rockbox] for the iRiver H100 series players support replaygain for some encoder formats. This is a rapidly evolving feature. There are no other portable players known to support replaygain.

The iPod features ''Soundcheck'', which seems to produce roughly the same normalization gains as replaygain, but doesnt provide an Album Gain.

=Additional reading=
* [http://replaygain.hydrogenaudio.org Original replaygain website] (this hasn't been updated since 2001, and everything there is outdated except for the description of the algorithm - but know that the 83dB SPL reference has since then be changed to 89 dB SPL ..)
* audio engineer Bob Katz's many interesting pages (e.g. [http://www.digido.com/portal/pmodule_id=11/pmdmode=fullscreen/pageadder_page_id=93/ this one]) is the best source to understand why replaygain is useful, and understand all that digital audio stuff. This actually was in part responsible for the design of replaygain by David Robinson in the first place, IIRC.

Ogg

2005-09-21T22:35:31Z

Nowhere man:

=Descrition=

Ogg is a digital media [[container format]], developed by [[Xiph]], that can encapsulate various bitstreams, for audio or video [[codec]]s, arbitrary data (e.g. [[subtitles]]) or [[metadata]]. Its first purpose was to be the native container for the free codecs developed by [[Xiph]], and it was developed alongside with the [[Vorbis]] codec.

==Features==

* encapsulation and interleave of multiple data streams,
* packet framing
* error detection
* seeking

All in a small, bounded percentage bitrate overhead.

Also, Ogg format specification is now published within the IETF in the following [[RFC]]s:

* RFC 3533 The Ogg Encapsulation Format Version 0
* RFC 3534 The application/ogg Media Type

=Main uses=

Here are the typical bitsreams contained in Ogg:

==Audio==

* [[Vorbis]] for general [[lossy]] compression (aka Ogg Vorbis, the first and classical use of Vorbis)
* [[Speex]] for voice [[lossy]] compression
* [[FLAC]] for [[lossless]] compression

==Video==

* [[Vorbis]] sound and any video codec, usually [[MPEG-4]] codecs like [[DivX]] or [[XviD]] (aka [[OGM]], Ogg Multimedia)
* [[Vorbis]] sound and [[Theora]] video, using only free and patent-clear (as claimed) formats from [[Xiph]] (aka Ogg Theora)

Lossless comparison

2005-09-21T19:41:42Z

Nowhere man: /* FLAC - Free Lossless Audio Codec */

Given the enormous amount of [[lossless]] audio compressor choices available, it is a very difficult task to choose the one most suited for each person's needs.

Several people only take into consideration compression performance when choosing a codec. But as the following table and article shows, there are several other features worth taking into consideration when making that choice.

For example, users wanting good multiplatform compatibility and robustness (E.G, people sharing live recordings) would favour [[WavPack]] or [[FLAC]]. Another user, looking for the very highest compression available, would go with [[OptimFROG]]. Someone wanting portable support would use [[FLAC]] or [[ALAC]], and so on.

En fin, this is not a matter worth getting too worked up about. If you later find out the codec you chose isn't the best for your needs, you can just transcompress to another format, without risk of losing quality.

==Comparison Table==



{| border="0" cellspacing="0"
| '''Features''' || {{Turquoise}} ALAC || {{Turquoise}} FLAC || {{Turquoise}} Monkey's || {{Turquoise}} OptimFROG || {{Turquoise}} Real Lossless || {{Turquoise}} Shorten
|-
| {{yellow}} Encoding speed || {{white}} average || {{light-green}} fast || {{light-green}} fast || {{orange}} slow || {{white}} average || {{green}} very fast
|-|
| {{yellow}} Decoding speed || {{green}} very fast || {{green}} very fast || {{light-green}} fast || {{orange}} slow || {{light-green}} fast || {{green}} very fast
|-|
| {{yellow}} Compression* || {{light-green}} 58,50% || {{light-green}} 58,70% || {{green}} 55,50% || {{green}} 54,70% || {{white}}   || {{orange}} 63,50%
|-|
| {{yellow}} Flexibility** || {{orange}} bad || {{green}} very good || {{green}} very good || {{green}} very good || {{orange}} bad || {{orange}} bad
|-
| {{white}}  
|-
| {{yellow}} Error handling || {{white}}   || {{green}} yes || {{orange}} no || {{green}} yes || {{white}}   || {{orange}} no
|-|
| {{yellow}} Seeking || {{green}} yes || {{green}} yes || {{green}} yes || {{green}} yes || {{green}} yes || {{green}} yes
|-|
| {{yellow}} Tagging || {{green}} QT tags || {{green}} FLAC tags || {{green}} ID3/APE || {{green}} ID3/APE || {{light-green}} Proprietary || {{orange}} no
|-|
| {{yellow}} Hardware support || {{green}} yes || {{green}} yes || {{orange}} no || {{orange}} no || {{orange}} no || {{orange}} no
|-|
| {{yellow}} Software support || {{orange}} bad || {{green}} very good || {{light-green}} good || {{white}} average || {{orange}} bad || {{green}} very good
|-|
| {{yellow}} Hybrid/lossy || {{orange}} no || {{orange}} no || {{orange}} no || {{green}} yes || {{orange}} no || {{orange}} no
|-|
| {{yellow}} ReplayGain || {{white}} sort of || {{green}} yes || {{orange}} no || {{green}} yes || {{orange}} no || {{orange}} no
|-|
| {{yellow}} RIFF chunks || {{white}}   || {{orange}} no || {{green}} yes || {{green}} yes || {{white}}   || {{green}} yes
|-|
| {{yellow}} Streaming || {{green}} yes || {{green}} yes || {{orange}} no || {{green}} yes || {{green}} yes || {{orange}} no
|-|
| {{yellow}} Pipe support || {{orange}} no || {{green}} yes || {{green}} yes || {{green}} yes || {{orange}} no || {{green}} yes
|-|
| {{yellow}} Open source || {{light-green}} Yes (decoding) || {{green}} yes || {{green}} yes || {{orange}} no || {{orange}} no || {{green}} yes
|-|
| {{yellow}} Multichannel || {{green}} yes || {{green}} yes || {{orange}} no || {{orange}} no || {{orange}} no || {{orange}} no
|-|
| {{yellow}} High resolution || {{green}} yes || {{green}} yes || {{green}} yes || {{green}} yes || {{orange}} no || {{orange}} no
|-|
| {{yellow}} OS support || {{light-green}} Win/Mac || {{green}} All || {{green}} All || {{light-green}} Win/Linux || {{green}} Win/Mac/Linux || {{green}} All
|-|
| {{gray}}   || {{gray}}   || {{gray}}   || {{gray}}   || {{gray}}   || {{gray}}   || {{gray}}  
|-|
| '''Features''' || {{Turquoise}} WavPack || {{Turquoise}} WMA || {{Turquoise}} LA || {{Turquoise}} TTA || {{Turquoise}} LPAC
|-|
| {{yellow}} Encoding speed || {{green}} very fast || {{white}} average || {{orange}} slow || {{green}} very fast || {{white}} average
|-|
| {{yellow}} Decoding speed || {{green}} very fast || {{white}} average || {{orange}} slow || {{green}} very fast || {{green}} very fast
|-|
| {{yellow}} Compression* || {{light-green}} 58% || {{green}} 56,30% || {{green}} 53,50% || {{light-green}} 57,10% || {{light-green}} 57,20%
|-|
| {{yellow}} Flexibility** || {{green}} very good || {{orange}} bad || {{white}} average || {{orange}} bad || {{orange}} bad
|-
| {{white}}  
|-
| {{yellow}} Error handling || {{green}} yes || {{green}} yes || {{orange}} no || {{green}} yes || {{orange}} no
|-|
| {{yellow}} Seeking || {{green}} yes || {{green}} yes || {{green}} yes || {{green}} yes || {{orange}} slow
|-|
| {{yellow}} Tagging || {{green}} ID3/APE || {{light-green}} Proprietary || {{light-green}} ID3v1 || {{light-green}} ID3 || {{orange}} no
|-|
| {{yellow}} Hardware support || {{green}} yes || {{orange}} no || {{orange}} no || {{green}} yes || {{orange}} no
|-|
| {{yellow}} Software support || {{light-green}} good || {{light-green}} good || {{orange}} bad || {{white}} average || {{white}} average
|-|
| {{yellow}} Hybrid/lossy || {{green}} yes || {{orange}} no || {{orange}} no || {{orange}} no || {{orange}} no
|-|
| {{yellow}} ReplayGain || {{green}} yes || {{orange}} no || {{orange}} no || {{green}} yes || {{orange}} no
|-|
| {{yellow}} RIFF chunks || {{green}} yes || {{orange}} no || {{green}} yes || {{orange}} no || {{green}} yes
|-|
| {{yellow}} Streaming || {{green}} yes || {{green}} yes || {{white}}   || {{orange}} no || {{orange}} no
|-|
| {{yellow}} Pipe support || {{green}} yes || {{green}} yes || {{green}} yes || {{orange}} no || {{white}}  
|-|
| {{yellow}} Open source || {{green}} yes || {{orange}} no || {{orange}} no || {{green}} yes || {{orange}} no
|-|
| {{yellow}} Multichannel || {{green}} yes || {{green}} yes || {{orange}} no || {{green}} yes || {{orange}} no
|-|
| {{yellow}} High resolution || {{green}} yes || {{green}} yes || {{orange}} no || {{green}} yes || {{green}} yes
|-|
| {{yellow}} OS support || {{green}} All || {{light-green}} Win/Mac || {{light-green}} Win/Linux || {{green}} All || {{light-green}} Win/Linux/Sol
|}

<nowiki>*</nowiki> Encoding speed, Decoding speed and Compression ratio are based on each encoder's default settings.

<nowiki>**</nowiki> Flexibility refers to the amount of encoding choices offered to the users (Fast/low compression, Slow/high compression and everything inbetween)

These are the most popular lossless codecs, in alphabetical order:

==ALAC - Apple Lossless Audio Codec== http://www.apple.com/itunes/import.html

[[ALAC]] is a codec developed by Apple for usage in [[Apple iPod|iPod]] and AirPort Express.

===ALAC PROS===
* Very fast decoding
* [[Open source]] ([http://craz.net/programs/itunes/alac.html decoding only])
* Hardware support ([[Apple iPod|iPod]], AirPort Express)
* Streaming support
* Tagging support (QT tags)
* Excellent hardware-software-lossy format integration with [[iTunes]]/iPod.
* Supports [[multichannel]] audio and [[high resolution]]s

===ALAC CONS===
* Closed source (encoding)
* Limited software support
* Compression efficiency not on par with other lossless codecs
* No hybrid/lossy mode

===ALAC Other features===
* Fits in the [[MP4]] container
* Can be used with the AirPort Express gadget

==FLAC - Free Lossless Audio Codec== http://flac.sourceforge.net/

[[FLAC]] is a lossless codec developed by Josh Coalson. It's part of the Xiph multimedia portfolio, along with [[Ogg]], [[Vorbis]], [[Speex]] and [[Theora]].

===FLAC PROS===
* [[Open source]]
* Very fast decoding
* Hardware support ([[Rio Karma|Karma]], Phatbox, etc.)
* Very good software support
* Error robustness
* Streaming support
* Supports [[multichannel]] audio and [[high resolution]]s
* Tagging support (FLAC tags)
* Pipe support
* [[ReplayGain]] compatible

===FLAC CONS===
* Relatively slow encoding
* No hybrid/lossy mode
* Doesn't support [[RIFF]] chunks

===FLAC Other features===
* Supports embedded CUE sheets (with [http://flac.sourceforge.net/faq.html#general__no_cuesheet_tags limitations])
* Includes MD5 hashes for quick integrity checking
* Fits the [[Ogg]] and [[Matroska]] containers

==LA - LosslessAudio== http://www.lossless-audio.com/

[[LA]] is a lossless codec developed by Michael Bevin.

===LA PROS===
* Very high compression
* Tagging support ([[ID3v1]])
* Supports [[RIFF]] chunks
* Pipe support

===LA CONS===
* Closed source
* Very slow encoding and decoding
* Doesn't support [[multichannel]] audio and [[high resolution]]s
* No hardware support
* No hybrid/lossy mode
* Bad software support
* Doesn't support [[ReplayGain]]

'''''It's important to mention that the LA foobar plugin is buggy and doesn't produce lossless streams!'''''

==LPAC== http://www.nue.tu-berlin.de/wer/liebchen/lpac.html

Lossless Predictive Audio Coder ([[LPAC]]) is a lossless codec developed by Tilman Liebchen. Development of it has been halted in favour of development of [[MPEG-4]] ALS.

===LPAC PROS===
* Reasonable compression ratios
* [[High resolution]] audio support
* Supports [[RIFF]] chunks

===LPAC CONS===
* Closed source
* No error robustness
* Slow seeking
* No tagging
* No [[multichannel]] support
* No hybrid/lossy mode
* No hardware support
* Doesn't support [[ReplayGain]]

==Monkey's Audio== http://www.monkeysaudio.com/

[[Monkey's Audio]] is a very efficient lossless compressor developed by Matt Ashland.

===APE PROS===
* [[Open source]]
* High efficiency
* Good software support
* Java version (multiplatform)
* Tagging support ([[ID3v1]], [[APE tags]])
* [[High resolution]] audio support
* Supports [[RIFF]] chunks (only in the GUI encoder)
* Pipe support (only in a [http://www.etree.org/shnutils/shntool/ special] version)

===APE CONS===
* No [[multichannel]] support
* No hybrid/lossy mode
* No hardware support
* No error robustness
* Doesn't support [[ReplayGain]]

===APE Other features===
* Supports APL image link files (similar to CUE sheets)

==OptimFROG== http://losslessaudiocompression.com/

[[OptimFROG]] is a lossless format developed by Florin Ghido to become the champion in audio compression.

===OFR PROS===
* Very high compression
* Good software support
* Error robustness
* Streaming support
* Supports [[high resolution]]s
* Hybrid/lossy mode
* Tagging support ([[ID3]], [[APE tags]])
* Supports [[RIFF]] chunks
* [[ReplayGain]] compatible

===OFR CONS===
* Closed source
* No [[multichannel]] audio support
* No hardware support
* Quite slow decoding

===OFR Other features===
* Supports 32bit float streams
* Includes MD5 hashes for quick integrity checking

==RealAudio Lossless== http://www.realnetworks.com/products/codecs/realaudio.html

RealAudio lossless is the lossless codec developed by Real Networks for their multimedia portfolio

===RAL PROS===
* Very fast decoding
* Streaming support
* Tagging support (proprietary)

===RAL CONS===
* Closed source
* No [[multichannel]] and [[high resolution]] audio support
* Little software support (Real Player)
* No hardware support
* Compression efficiency not on par with other lossless codecs
* No hybrid/lossy mode
* No pipe support
* Doesn't support [[ReplayGain]]

==Shorten== http://www.etree.org/shnutils/shorten/

[[Shorten]] is a very old and featureless lossless codec developed by Tony Robinson at SoftSound.

===SHN PROS===
* [[Open source]]
* Fast decoding
* Very good software support
* Supports [[RIFF]] chunks
* Pipe support

===SHN CONS===
* Quite inefficient
* No [[multichannel]] or [[high resolution]] audio support
* No hybrid/lossy mode
* No error robustness
* Not streamable
* No hardware support
* No native tagging
* Doesn't support [[ReplayGain]]

==True Audio (TTA)== http://tta.corecodec.org/

[[TTA]] is a new lossless codec developed by a team of russian programmers.

===TTA PROS===
* [[Open source]]
* Good efficiency
* Hardware support (obscure DVD player)
* Supports [[multichannel]] audio and [[high resolution]]s
* Tagging support ([[ID3]])
* [[ReplayGain]] compatible
* Error robustness

===TTA CONS===
* No streaming support
* No hybrid/lossy mode
* Doesn't support [[RIFF]] chunks
* No pipe support

===TTA Other features===
* Fits the [[Matroska]] container

==WavPack== http://www.wavpack.com/

[[WavPack]] is a fast and featureful lossless codec developed by David Bryant.

===WV PROS===
* [[Open source]]
* Very fast decoding
* Good efficiency
* Error robustness
* Streaming support
* Hardware support ([http://www.rockbox.org/ RockBox])
* Supports [[multichannel]] audio and [[high resolution]]s
* Hybrid/lossy mode
* Tagging support ([[ID3v1]], [[APE tags]])
* Supports [[RIFF]] chunks
* Ability to create self extracting files for Win32 platform
* Pipe support
* Good software support
* [[ReplayGain]] compatible

===WV CONS===
* No cons

===WV Other features===
* Supports 32bit float streams
* Supports embedded CUE sheets
* Includes MD5 hashes for quick integrity checking
* Can encode in both symmetrical and assymmetrical modes.
* Fits the [[Matroska]] container

==Windows Media Audio Lossless== http://www.microsoft.com/windows/windowsmedia/9series/codecs/audio.aspx

WMA Lossless is the lossless codec developed by Microsoft to be featured in their Windows Media codec portfolio.

===WMAL PROS===
* Streaming support
* Very good software support
* Supports [[multichannel]] audio and [[high resolution]]s.
* Tagging support (proprietary)
* Pipe support

===WMAL CONS===
* Closed source
* No hybrid/lossy mode
* No hardware support (but it's likely to appear sooner or later)
* Doesn't support [[RIFF]] chunks
* Doesn't support [[ReplayGain]]

===WMAL Other features===
* Fits the [[ASF]] container

==Oddball Formats==

There are several old lossless formats that aren't being featured in the article above. Reasons are: lack of widespread support, lack of features, bad efficiency and, most importantly, it seems noone is really interested in them.

Most of those would have disappeared by now, but they are being preserved for posterity at [[User:Rjamorim|rjamorim]]'s [http://www.rjamorim.com/rrw/ ReallyRareWares]

===Advanced Digital Audio (ADA)===

* http://www.rjamorim.com/rrw/ada.html

===Bonk===

* http://www.logarithmic.net/pfh/bonk

===Marian's a-Pac===

* http://www.marian.de/en/downloads#APAC
* http://www.rjamorim.com/rrw/apac.html

===AudioZip===

* http://www.rjamorim.com/rrw/audiozip.html

===Dakx WAV===

* http://www.dakx.com/
* http://www.rjamorim.com/rrw/daxwav.html

===Entis Lab MIO===

* http://www.entis.gr.jp/eri/frame.html
* http://www.rjamorim.com/rrw/mio.html

===LiteWave===

* http://www.clearjump.com/products/LiteWave.html
* http://www.rjamorim.com/rrw/litewave.html

===Pegasus SPS===

* http://www.krishnasoft.com/sps.htm
* http://www.rjamorim.com/rrw/pegasussps.html

===RKaudio===

* http://www.msoftware.co.nz/downloads_page.php
* http://rksoft.virtualave.net/rkau.html

===Split2000===

* http://www.rjamorim.com/rrw/split2000.html

===Sonarc===

* http://www.rjamorim.com/rrw/sonarc.html

===VocPack===

* http://www.rjamorim.com/rrw/vocpack.html

===WavArc===

* http://www.rjamorim.com/rrw/wavarc.html

===WaveZip/MUSICompress===

* http://members.aol.com/_ht_a/sndspace/
* http://www.rjamorim.com/rrw/wavezip.html

==Links==

Some links to lossless format compression comparisons:

* [http://web.inter.nl.net/users/hvdh/lossless/lossless.htm Hans Heijden's] (used as reference to build the table);
* [http://members.home.nl/w.speek/comparison.htm Speek's];
* [http://foobar2000.net/lossless/ Guruboolez'] - comparing only classical music;
* [http://studwww.ugent.be/~jdebock/lossless_audio_compression_test.htm Johan De Bock's] - aimed only at the maximum compression setting for each codec (based on a somewhat limited set of samples, however).

* Go to the [http://www.hydrogenaudio.org/forums/index.php?showtopic=33226 Hydrogenaudio thread] to discuss this article.

Vorbis

2005-09-21T19:41:23Z

Nowhere man: /* External links */

[[image:fish.png|right|]]

=Introduction=
'''Vorbis''' ([http://www.vorbis.com www.vorbis.com]) is a fully open, non-proprietary, patent-free (subject to [http://www.hydrogenaudio.org/forums/index.php?showtopic=13531 speculation]), and royalty-free, general-purpose compressed audio format for mid to high quality (8khz-48.0kHz, 16+ bit, [[multichannel]]) audio and music at fixed and variable bitrates from 16 to >256 kbps/channel. This places vorbis in the same competitive class as audio representations such as MPEG-4 ([[AAC]]), and similar to, but higher performance [[MP3]], TwinVQ ([[VQF]]), [[WMA]] and [[PAC]].

Vorbis is the first of a planned family of Ogg multimedia coding formats being developed as part of Xiph.org's ogg multimedia project.

Informal listening test suggests Vorbis to be comparable to MPEG-4 [[AAC]] at most bitrates and [[MPC]] at 128 kbps. Transparency is generally reached at about 150-170 kbps (-q 5) (with some exceptions). The encoder is reasonably young and unoptimized, so further improvements can always be expected.

Unfortunately, Xiph.org has failed to improve Vorbis at a steady rate since its initial 1.0 release in July 2002 (due to other developement projects and time constraints). Since then development has been led by other coders such as [http://sjeng.org/vorbisgt3.html Garf] and [http://www.geocities.jp/aoyoume/aotuv/ Aoyumi]. Aoyumi's AoTuV series of encoders was incorporated into the September 2004 release of 1.1, which brought about the first quality improvements across the board for 2 years. Currently Aoyumi is working on AoTuv Beta 4 and future releases.

Vorbis has had success with many recent video game titles employing Vorbis as opposed to MP3 (with Epic Games' Unreal Tournament 2003 and Unreal Tournament 2004, the PC port of Microsoft's Halo and Uru being notable examples). It's also an official part of the [http://www.openal.org/extensions.html OpenAL] extension library.

==Pros==
* Free (as in speech), Open Source and claimed to be patent free
* Good all-round performance (>48 kbps - a leading codec at [http://www.rjamorim.com/test/multiformat128/results.html 128 kbps])
* Well written [http://www.xiph.org/ogg/vorbis/docs.html specs]
* Several portable [http://wiki.hydrogenaudio.org/index.php?title=Ogg_Vorbis#Hardware hardware players]
* Suitable for internet-streaming (via [http://www.icecast.org/ Icecast] and other methods)
* Fully [[gapless]] playback
* High potential for further tuning
* Structured to allow the design for a hybrid filterbank.

==Cons==
* Limited official development (third-party developement is always encouraged)
* Current implementations are more computationally intensive to encode and decode than MP3 (Vorbis 2.0 seeks to overcome this limitation by slimlining the encoder)
* Multichannel input mappings for 5.1, Ambisonic-B, and other config have no channel coupling and aren't tuned (expect sub-optimal results until code is improved).

=Technical details used in compression=
* Multiple block sizes for window switching including overlap (varies for different modes, powers of two only)
* Customly designed [[window function]] is applied similiar to the sine window '''<small>wk = sin(PI/2*sin^2[PI/2n*(k+0.5)])</small>''' (good sidelobe rejection)
* Psychoacoustics masking exploited via an ([[ATH]] model)
* Masking curves derived from ''emperically'' adjusted set of [http://www.zainea.com/masking2.htm Ehmer Curves]
* Modified Discrete Cosine Transform ([[MDCT]]) is used for noise analysis.
* Fast Fourier Transform ([[FFT]]) is used for tonal analysis.
* Global masking curve is a mixture between calculated FFT+MDCT curves and ATH curves.
* The noise-floor (envelope) is calculate using global masking curve & piecewise linear approximation divded by spectrum to generate the residue (fine detail).
* [[Noise normalization]] is applied to compensate for energy lost in certain frequency bands due to quantization ''(main cause metallic warbling in MP3)''
* The channels are coupled ''strictly'' by residue using ([http://us.xiph.org/ogg/vorbis/doc/stereo.html point/phase stereo] and lossless).
* Multistage [[Vector quantization]] is used for coding the noise-floor and residue backend using ''trained'' codebooks.
* [[Huffman coding]] is used to minimize vector codeword redundancy.

=Software=
'''Encoders'''
* [[Oggenc]] official command-line encoder (Win32/Posix).
* [http://www.rarewares.org/ogg.html OggdropXPd] advanced drag-and-drop encoder by John33 (Win32)
* [http://www.saunalahti.fi/cse/foobar2000/ foo_vorbisenc] vorbis encoder library for Foobar2000 (Win32)

'''Decoders'''
* [[Ogg123]] for Unix systems (GPL), a very simple to use command-line player. (Win32/Posix)
* [http://www.rarewares.org/ogg.html OggDec] for Windows, by John33, a very featureful command line decoder. (Win32)
* [http://qtcomponents.sourceforge.net/ QuickTime Component] (Allows playback in [[QuickTime]]/[[iTunes]]) (Win32)
* [http://corevorbis.corecodec.org/ CoreVorbis] (DirectShow) (Win32)
* [http://www.illiminable.com/ogg/ illiminable Ogg Directshow Filters] (Also plays Speex, Theora and FLAC) (Win32)

=Supported Digital Audio Players=
The following list contains some players that support Vorbis playback.
A [http://wiki.xiph.org/index.php/PortablePlayers longer list] can be found at xiph's wiki.
* [[iRiver H-Series]]
* [[MPIO H-Series]]
* [[Rio Karma]]
* [http://www.ifreemax.com/ FreeMax] FW-960
* [http://www.iaudiophile.net/ iAudio] [[IAudio M3|M3]], U2, G3, 5
* [[Neuros]]
* [http://www.samsung.com/Products Samsung]
* [http://www.yepp.co.kr/ Yepp] YP-T6, YP-T7, YP-C1, YP-F1

=External links=
The following links contain information surrounding the Ogg Vorbis codec that can be found on Hydrogenaudio and elsewhere throughout the web.

* [[Ogg]] (Container)
* [http://www.vorbis.com Vorbis official website] (requires updating)
* [http://en.wikipedia.org/wiki/Vorbis Vorbis at Wikipedia.]
* [http://www.audiocoding.com/modules/wiki/?page=Ogg+Vorbis Ogg Vorbis at AudioCoding]
* [http://www.rarewares.org/ogg.html Ogg Vorbis binaries at Rarewares. ]
* [http://www.rjamorim.com/test/ Listening tests comparing Vorbis against MP3, AAC, WMA, etc.]
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=15049 Recommended settings thread for encoding with Vorbis.]
* [http://wiki.hydrogenaudio.org/index.php?title=EAC_and_Ogg_Vorbis Configuring EAC and Vorbis as an external command-line encoder]
* [http://www.geocities.jp/aoyoume/aotuv/ Aoyumi homepage tuned versions of Vorbis 1.1 encoder and current beta binaries.]
* [http://homepage3.nifty.com/blacksword/index_e.htm Archer/Lancer homepage optimized versions of AoTuV Beta 3 Vorbis encoder and other SSE optmizations. ]
* [http://www.free-comp-shop.com/vorbis.pdf Keith Wright rendition of understanding the MDCT in Vorbis by defineing it's basic trig properties (good read)]
* [http://www.xiph.org Xiph.org Foundation]
* [http://wiki.xiph.org/index.php/Bounties Xiph.org Vorbis bounties]

Vorbis

2005-09-21T19:39:54Z

Nowhere man: /* Introduction */

[[image:fish.png|right|]]

=Introduction=
'''Vorbis''' ([http://www.vorbis.com www.vorbis.com]) is a fully open, non-proprietary, patent-free (subject to [http://www.hydrogenaudio.org/forums/index.php?showtopic=13531 speculation]), and royalty-free, general-purpose compressed audio format for mid to high quality (8khz-48.0kHz, 16+ bit, [[multichannel]]) audio and music at fixed and variable bitrates from 16 to >256 kbps/channel. This places vorbis in the same competitive class as audio representations such as MPEG-4 ([[AAC]]), and similar to, but higher performance [[MP3]], TwinVQ ([[VQF]]), [[WMA]] and [[PAC]].

Vorbis is the first of a planned family of Ogg multimedia coding formats being developed as part of Xiph.org's ogg multimedia project.

Informal listening test suggests Vorbis to be comparable to MPEG-4 [[AAC]] at most bitrates and [[MPC]] at 128 kbps. Transparency is generally reached at about 150-170 kbps (-q 5) (with some exceptions). The encoder is reasonably young and unoptimized, so further improvements can always be expected.

Unfortunately, Xiph.org has failed to improve Vorbis at a steady rate since its initial 1.0 release in July 2002 (due to other developement projects and time constraints). Since then development has been led by other coders such as [http://sjeng.org/vorbisgt3.html Garf] and [http://www.geocities.jp/aoyoume/aotuv/ Aoyumi]. Aoyumi's AoTuV series of encoders was incorporated into the September 2004 release of 1.1, which brought about the first quality improvements across the board for 2 years. Currently Aoyumi is working on AoTuv Beta 4 and future releases.

Vorbis has had success with many recent video game titles employing Vorbis as opposed to MP3 (with Epic Games' Unreal Tournament 2003 and Unreal Tournament 2004, the PC port of Microsoft's Halo and Uru being notable examples). It's also an official part of the [http://www.openal.org/extensions.html OpenAL] extension library.

==Pros==
* Free (as in speech), Open Source and claimed to be patent free
* Good all-round performance (>48 kbps - a leading codec at [http://www.rjamorim.com/test/multiformat128/results.html 128 kbps])
* Well written [http://www.xiph.org/ogg/vorbis/docs.html specs]
* Several portable [http://wiki.hydrogenaudio.org/index.php?title=Ogg_Vorbis#Hardware hardware players]
* Suitable for internet-streaming (via [http://www.icecast.org/ Icecast] and other methods)
* Fully [[gapless]] playback
* High potential for further tuning
* Structured to allow the design for a hybrid filterbank.

==Cons==
* Limited official development (third-party developement is always encouraged)
* Current implementations are more computationally intensive to encode and decode than MP3 (Vorbis 2.0 seeks to overcome this limitation by slimlining the encoder)
* Multichannel input mappings for 5.1, Ambisonic-B, and other config have no channel coupling and aren't tuned (expect sub-optimal results until code is improved).

=Technical details used in compression=
* Multiple block sizes for window switching including overlap (varies for different modes, powers of two only)
* Customly designed [[window function]] is applied similiar to the sine window '''<small>wk = sin(PI/2*sin^2[PI/2n*(k+0.5)])</small>''' (good sidelobe rejection)
* Psychoacoustics masking exploited via an ([[ATH]] model)
* Masking curves derived from ''emperically'' adjusted set of [http://www.zainea.com/masking2.htm Ehmer Curves]
* Modified Discrete Cosine Transform ([[MDCT]]) is used for noise analysis.
* Fast Fourier Transform ([[FFT]]) is used for tonal analysis.
* Global masking curve is a mixture between calculated FFT+MDCT curves and ATH curves.
* The noise-floor (envelope) is calculate using global masking curve & piecewise linear approximation divded by spectrum to generate the residue (fine detail).
* [[Noise normalization]] is applied to compensate for energy lost in certain frequency bands due to quantization ''(main cause metallic warbling in MP3)''
* The channels are coupled ''strictly'' by residue using ([http://us.xiph.org/ogg/vorbis/doc/stereo.html point/phase stereo] and lossless).
* Multistage [[Vector quantization]] is used for coding the noise-floor and residue backend using ''trained'' codebooks.
* [[Huffman coding]] is used to minimize vector codeword redundancy.

=Software=
'''Encoders'''
* [[Oggenc]] official command-line encoder (Win32/Posix).
* [http://www.rarewares.org/ogg.html OggdropXPd] advanced drag-and-drop encoder by John33 (Win32)
* [http://www.saunalahti.fi/cse/foobar2000/ foo_vorbisenc] vorbis encoder library for Foobar2000 (Win32)

'''Decoders'''
* [[Ogg123]] for Unix systems (GPL), a very simple to use command-line player. (Win32/Posix)
* [http://www.rarewares.org/ogg.html OggDec] for Windows, by John33, a very featureful command line decoder. (Win32)
* [http://qtcomponents.sourceforge.net/ QuickTime Component] (Allows playback in [[QuickTime]]/[[iTunes]]) (Win32)
* [http://corevorbis.corecodec.org/ CoreVorbis] (DirectShow) (Win32)
* [http://www.illiminable.com/ogg/ illiminable Ogg Directshow Filters] (Also plays Speex, Theora and FLAC) (Win32)

=Supported Digital Audio Players=
The following list contains some players that support Vorbis playback.
A [http://wiki.xiph.org/index.php/PortablePlayers longer list] can be found at xiph's wiki.
* [[iRiver H-Series]]
* [[MPIO H-Series]]
* [[Rio Karma]]
* [http://www.ifreemax.com/ FreeMax] FW-960
* [http://www.iaudiophile.net/ iAudio] [[IAudio M3|M3]], U2, G3, 5
* [[Neuros]]
* [http://www.samsung.com/Products Samsung]
* [http://www.yepp.co.kr/ Yepp] YP-T6, YP-T7, YP-C1, YP-F1

=External links=
The following links contain information surrounding the Ogg Vorbis codec that can be found on Hydrogenaudio and elsewhere throughout the web.

* [[Ogg]] (Container)
* [http://www.vorbis.com Ogg Vorbis official website] (requires updating)
* [http://en.wikipedia.org/wiki/Vorbis Ogg Vorbis at Wikipedia.]
* [http://www.audiocoding.com/modules/wiki/?page=Ogg+Vorbis Ogg Vorbis at AudioCoding]
* [http://www.rarewares.org/ogg.html Ogg Vorbis binaries at Rarewares. ]
* [http://www.rjamorim.com/test/ Listening tests comparing Vorbis against MP3, AAC, WMA, etc.]
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=15049 Recommended settings thread for encoding with Vorbis.]
* [http://wiki.hydrogenaudio.org/index.php?title=EAC_and_Ogg_Vorbis Configuring EAC and Vorbis as an external command-line encoder]
* [http://www.geocities.jp/aoyoume/aotuv/ Aoyumi homepage tuned versions of Vorbis 1.1 encoder and current beta binaries.]
* [http://homepage3.nifty.com/blacksword/index_e.htm Archer/Lancer homepage optimized versions of AoTuV Beta 3 Vorbis encoder and other SSE optmizations. ]
* [http://www.free-comp-shop.com/vorbis.pdf Keith Wright rendition of understanding the MDCT in Vorbis by defineing it's basic trig properties (good read)]
* [http://www.xiph.org Xiph.org Foundation]
* [http://wiki.xiph.org/index.php/Bounties Xiph.org Vorbis bounties]

Talk:Vorbis

2005-09-21T18:34:43Z

Nowhere man:

I don't see any purpose rehashing this whole legal thing again. If peoeple are interested in the discussion they should just read the thread. HotshotGG 17 June 2005 (EST)

: Well, I lifted that text directly from Wikipedia, and I thought it to be very interesting, as it clarifies the situation while doing caveats that everything could be just FUD from the competitors. rjamorim 00:55, 19 Jun 2005 (CDT)

:: Yeah that's true, I understand were you are coming from. Wikipedia just has it their reguarding the liscense and the whole issues is up in the air. 00:12, HotshotGG 20 Jun 2005 (EST)

::: Also, I believe just a small paragraph summarizing the whole bruhaha is much better that telling the article readers "read and understand these 15 pages of messily organized and barely chronological forum posts". But that's just me. :B rjamorim 10:58, 20 Jun 2005 (CDT)

::: I am overdueing it a little with this page. I just want to be as specific as possible though for anyone who visits it ;-d. Maybe we should add the xiph logo to as well? hmm, also technical Vorbis doesn't use a straight MDCT it uses a FFT to do some tone masking ;-O (that's really irrlevant though). The specs won't tell the user too much about encoding, therefore I'm trying to fill in some technical gaps here. HotshotGG 2:30, 23 June 2005 (EST)

----

As Ogg is the container format and Vorbis the codec, wouldn't it be more accurate to have a [[Vorbis]] and an [[Ogg]] page, along with this one being a redirection or a placeholder page that contains links to the two formers? [[User:Nowhere man|Nowhere man]] 13:34, 21 Sep 2005 (CDT)