Hydrogenaudio Knowledgebase - User contributions [en]

Free Lossless Audio Codec

2007-01-06T10:33:07Z

Guruboolez:

{{Codec Infobox
| name = FLAC
| logo = [[Image:FLAC logo.gif]]
| type = lossless
| purpose = Popular open source patent free lossless compression scheme.
| maintainer = Josh Coalson, Xiph Community
| recommended_encoder = FLAC encoder
| recommended_text = FLAC v1.1.3
| website = http://flac.sourceforge.net/
}}
'''FLAC''' stands for Free Lossless Audio Codec. Grossly oversimplified, FLAC is similar to [[MP3]], but [[lossless]], meaning that audio is compressed in FLAC without any loss in quality. This is similar to how Zip works, except with FLAC you will get much better compression because it is designed specifically for audio, and you can play back compressed FLAC files in your favorite player (or your car or home stereo, if supported) just like you would an MP3 file.

==General aspects of the format==
FLAC is freely available and supported on most operating systems, including Windows, UNIX (Linux, *BSD, Solaris, OS X, IRIX), BeOS, OS/2, and Amiga. There are build systems for autotools, MSVC, Watcom C, and Project Builder.

The FLAC project consists of:
* the stream format
* reference encoders and decoders in library form
* flac, a command-line program to encode and decode FLAC files
* metaflac, a command-line metadata editor for FLAC files
* input plugins for various music players

When we say that FLAC is ''free'' it means more than just that it is available at no cost. It means that the specification of the format is fully open to the public to be used for any purpose (the FLAC project reserves the right to set the FLAC specification and certify compliance), and that neither the FLAC format nor any of the implemented encoding/decoding methods are covered by any known patent. It also means that all the source code is available under open-source licenses. It is the first truly open and free lossless audio format.

Some claim FLAC is the most widely used lossless compression format on UNIX systems (though it seems more likely that shn retains that honor on all OS platforms).
FLAC files also can be placed inside an Ogg container using libOggFLAC and libOggFLAC++.

==Features==
* '''Lossless:''' The encoding of audio (PCM) data incurs no loss of information, and the decoded audio is bit-for-bit identical to what went into the encoder. Each frame contains a 16-bit CRC of the frame data for detecting transmission errors. The integrity of the audio data is further insured by storing an MD5 signature of the original unencoded audio data in the file header, which can be compared against later during decoding or testing.
* '''Fast:''' FLAC is asymmetric in favor of decode speed. Decoding requires only integer arithmetic, and is much less compute-intensive than for most perceptual codecs. Real-time decode performance is easily achievable on even modest hardware.
* '''Hardware support:''' Because of FLAC's free reference implementation and low decoding complexity, FLAC is currently the only lossless codec that has any kind of hardware support.
* '''Streamable:''' Each FLAC frame contains enough data to decode that frame. FLAC does not even rely on previous or following frames. FLAC uses sync codes and CRCs (similar to MPEG and other formats), which, along with framing, allow decoders to pick up in the middle of a stream with a minimum of delay.
* '''Seekable:''' FLAC supports fast sample-accurate seeking. Not only is this useful for playback, it makes FLAC files suitable for use in editing applications.
* '''Flexible metadata:''' New metadata blocks can be defined and implemented in future versions of FLAC without breaking older streams or decoders. Currently there are metadata types for tags, cue sheets, and seek tables. Applications can write their own APPLICATION metadata once they register an ID.
* '''Suitable for archiving:''' FLAC is an open format, and there is no generation loss if you need to convert your data to another format in the future. In addition to the frame CRCs and MD5 signature, flac has a verify option that decodes the encoded stream in parallel with the encoding process and compares the result to the original, aborting with an error if there is a mismatch.
* '''Convenient CD archiving:''' FLAC has a ''cue sheet'' metadata block for storing a CD table of contents and all track and index points. For instance, you can rip a CD to a single file, then import the CD's extracted cue sheet while encoding to yield a single file representation of the entire CD. If your original CD is damaged, the cue sheet can be exported later in order to burn an exact copy.
* '''Error resistant:''' Because of FLAC's framing, stream errors limit the damage to the frame in which the error occurred, typically a small fraction of a second worth of data. Contrast this with some other lossless codecs, in which a single error destroys the remainder of the stream.

==Pros==
* Portable to many systems
* Source open and freely licenced
* Hardware support (PhatBox, Kenwood MusicKeg, Rio Karma, etc. See below)
* Streaming support
* Extremely fast decoding
* Supports multichannel and high resolution streams
* Supports [[ReplayGain]]
* Supports cue-sheet (with some limitations)
* Gaining wide use as successor to [[Shorten]]

==Cons==
* Compresses less efficiently than other popular modern compressors ([[Monkey's Audio]], [[OptimFROG]])
* Higher compression modes slow, for little gain over the default setting.

==Hardware and software that support FLAC==
For a more comprehensive list see the [http://flac.sourceforge.net/links.html FLAC links page].

===Hardware===
====Home stereo====
* [http://www.request.com/us/ AudioReQuest] music servers
* [http://www.avegasystems.com/ Avega Systems]' wireless [http://www.avegasystems.com/_documents/Oyster_Specifications.pdf Oyster] loudspeakers
* Digital Techniques' "iStereo" [http://www.digitaltechniques.com/M300A_Overview.html M300A Digital Music Player]
* Escient's [http://www.escient.com/ FireBall servers (E2-40/160/300, DVDM-300)]
* [http://www.hermstedt.com/english/hifidelio/hifidelio.html Hifidelio]
* [http://www.imuse.us/ iMuse] audio/video media servers
* Meda Systems' [http://www.medainc.com/ Bravo servers]
* The [http://www.cesweb.org/attendees/show_floor/product_locator/product_details.asp?prodid=5181 MS300 Music Server] by McIntosh Laboratory
* Olive's [http://www.olive.us/ Symphony] wireless digital music center
* [http://www.phatnoise.com/products/homeplayer/index.php PhatNoise Home Digital Media Player]
* [http://www.numark.com/ Numark]'s DJ equipment (HDX and CDX turntables, HDMIX mixer)
* [http://www.mock.com/receiver/ Rio Reciever] and Dell Digital Audio Receiver
* [http://www.rokulabs.com/products/photobridge/features.php Roku PhotoBridge HD] (with [http://homepage.ntlworld.ie/p.mc.quillan/FLAC_V0.7.zip plugin])
* [http://www.skipjam.com/ SkipJam]'s networked audio/video devices
* [http://www.sonos.com/ Sonos Digital Music System]
* Slim Devices' [http://www.slimdevices.com/pi_transporter.html Transporter] and [http://www.slimdevices.com/pi_squeezebox.html Squeezebox] networked audi players
* [http://www.z500series.com/ Zensonic Z500 Networked DVD Media Player]
* Ziova's [http://www.ziova.com/cs510.php CS510] and [http://www.ziova.com/cs505.php CS505] network media players

====Car stereo====
* [http://www.phatnoise.com/products/digitalmediaplayers/kenwood_music_keg.php Kenwood Music Keg]
* [http://www.phatnoise.com/products/digitalmediaplayers/index.php PhatBox]

====Portable====
* [[Apple iPod]] with [[Rockbox]] firmware
* Bluedot's [http://www.digitalworldtokyo.com/2006/07/bluedot_pmp_runs_linux_loves.php BMP-1430]
* Green Apple's portable media player: [http://www.apod.com.cn/show_products.asp?photoID=437 AP3000]
* [[iAudio M3]] and X5
* [[iRiver]] iHP-120/iHP-140 with [[Rockbox]] firmware
* [[Iwod G10]]
* [[Rio Karma]]
* TrekStor's [http://www.trekstor.de/en/products/detail_mp3.php?pid=66 Vibez]

===Software===
====Players====
* [http://koti.welho.com/hylinen/apollo/ Apollo]
* [http://cogosx.sourceforge.net Cog] — for Mac OS X
* [[foobar2000]]
* [[JRiver Media Center]]
* [http://fondriest.frederic.free.fr/realisations/lamip/ LAMIP]
* [[MediaMonkey]]
* [http://www.mplayerhq.hu/ MPlayer]
* [http://www.mythtv.org/ MythTV]
* [http://www.quinnware.com/ QCD] ([http://www.quinnware.com/list_plugins.php?type=input plugin])
* [http://www.videolan.org/ VLC]
* [http://www.vuplayer.com/vuplayer.htm VUPlayer]
* [[Winamp]]
* [[Windows Media Player]] and other directshow-based players (MPC, TCMP, RadLight) (with [http://www.illiminable.com/ogg/ Illiminable's directshow filters] or [http://corecodec.org/projects/coreflac CoreFLAC])
* [http://xine.sourceforge.net/ Xine]
* [[XMMS]]
* [http://www.un4seen.com/ XMplay]

====Frontends (Windows)====
* [http://www.uninformative.com/flacattack/ Flacattack]
* Custom [http://members.home.nl/w.speek/flac.htm Windows Frontend] (by Speek)
* [http://www.unifront.boereck.de/ UniversalFront] by Böreck
* [http://home.vxu.se/mdati00/frontah/ Frontah] by Madah
* [http://www.webearce.com.ar/ MAREO] by Kwambis

====Frontends (Mac)====
* [http://www.danrules.com/macflac/ MacFLAC]
* [http://www.sbooth.org/Max/ Max]
* [http://members.rogers.com/beamsplitter/ RipBeak]
* [http://www.versiontracker.com/dyn/moreinfo/macosx/21952 xACT]

====Converters====
* [http://www.dbpoweramp.com/ dBpowerAMP] Music Converter / Audio Player / CD Writer
* [http://www.mediamonkey.com/ MediaMonkey] Music Manager / Audio Player / CD Writer
* [http://www.germanixsoft.de/ GX:Transcoder] Music converter

====Editors====
* [[Adobe Audition]]

====CD writers/rippers====
* [http://www.ahead.de Ahead Nero Burning Rom]
* [http://arson.sourceforge.net/ Arson]
* [http://www.burnatonce.com/ burnatonce]
* [http://www.burrrn.net Burrrn] Audio CD burner
* [[Exact Audio Copy]] CD Ripper
* [http://cdexos.sourceforge.net CDex] CD ripper
* [http://www.cdwave.com/ CD Wave]

====Taggers====
* [http://www.saunalahti.fi/cse/files/Tag.zip Case's Tag] command line tagger
* [http://users.otenet.gr/~jtcliper/tgf/ The GodFather] Tagger / Music manager
* [http://www.mp3tag.de/en/index.html Mp3tag] Universal Tag Editor
* [http://sbooth.org/Tag/ Tag] — for Mac OS X 10.4 (Tiger)
* [http://flac.sourceforge.net/documentation.html#metaflac metaflac] - for general metadata (including Vorbis comments) maintenance

====Other tools====
* [http://www.burrrn.net/mrq/ Mr. QuestionMan]
* [http://www.bitattack.ro/ai/ Audio Identifier]
* [http://www.bunkus.org/videotools/mkvtoolnix/ mkvtoolnix] - tool to multiplex FLAC streams inside the Matroska container
* [http://flac.sourceforge.net/documentation.html#metaflac metaflac] - for general metadata (including Vorbis comments) maintenance, also to calculate [[replaygain]] values for FLAC files lacking such

...and many more; see the [http://flac.sourceforge.net/links.html#software FLAC software section] and [http://flac.sourceforge.net/download.html#extras download section] for a more comprehensive list.

==Frequently asked questions==
''Question:'' Does the compression level affect decompression speed?

''Short Answer'': No.

''Long Answer'': In truth, the compression level does affect the decompression speed, but the difference between the various compress levels can barely be measured and is too small to be noticed, even on low-end machines.

''Question:'' What is the best compression level for encoding my music?

''Short Answer'': The default setting, 5.

''Long Answer'': Encoding at the default setting will give the best balance between compression and encoding speed. Encoding at 8 can more than quadruple the encoding time, while having an insignificant effect on compression.

==See also==
* [[Lossless]]
* [[Lossless Comparison]]

==Externals links==
* [http://flac.sourceforge.net FLAC website]
* [http://flac.sourceforge.net/download.html FLAC download]
* [http://flac.sourceforge.net/format.html Detailed description of the FLAC format]
* [http://flac.sourceforge.net/documentation.html FLAC documentation]
* [http://flac.sourceforge.net/faq.html FLAC FAQ]
* [http://people.ucsc.edu/~rswilson/flactest Omion's FLAC "File Size vs. Decoding Speed" test] - a very thorough test on [[FLAC#Frequently_Asked_Questions|the influence of the chosen encoding level on the decoding speed of FLAC]]; the only one so far to have covered FLAC's --super-secret-totally-impractical-compression-level to this extent as well.
* [http://www.losslessaudioblog.com/ The Lossless Audio Blog] Lossless Audio News & Information Site.

[[Category:Lossless]]

Artifact

2006-06-10T21:42:01Z

Guruboolez: /* Different kind of artifacts */

An '''artifact''' is a noticeable difference between an uncompressed signal and a [[lossy|lossily]]-compressed copy.
[[Lossy]] encoding can result in very different kind of artifacts/distortions. Sometimes it's not easy to define why the encoding is non-transparent. There are however many typical encoding artifacts.

===Different kind of artifacts===

* '''[[pre echo]]''': pre-echo consists in a small amount of noise used to appear just before a contrasted sound events (like percussive instruments). The original transients are therefore smeared: "___shhhTak" instead of "____Tak".
''Illustrative samples'': [[http://www-ccrma.stanford.edu/~bosse/ castanets.wav]], [[http://anonymousriver.hp.infoseek.co.jp/castanets2/index.html castanets2.wav]]

The phenomenon could sometimes be visualised on a frequency editor:
[[Image:Preecho.png]]

To listen to the corresponding artifact, click [[http://audiotests.free.fr/tests/wiki/castanets2.mp3 here]]

* '''ringing''':

* '''warbling''':

* '''coarseness''':

* '''stereo collapse''':

===External links===
*[http://ff123.net/training/training.html ff123's Audio Artifact Training Page]

{{stub}}

File:Preecho.png

2006-06-10T21:32:30Z

Guruboolez: illustration of pre-echo phenomenon

illustration of pre-echo phenomenon

Artifact

2006-06-10T21:02:21Z

Guruboolez: /* Different kind of artifacts */

An '''artifact''' is a noticeable difference between an uncompressed signal and a [[lossy|lossily]]-compressed copy.
[[Lossy]] encoding can result in very different kind of artifacts/distortions. Sometimes it's not easy to define why the encoding is non-transparent. There are however many typical encoding artifacts.

===Different kind of artifacts===

* '''[[pre echo]]''': pre-echo consists in a small amount of noise used to appear just before a contrasted sound events (like percussive instruments). The original transients are therefore smeared: "___shhhTak" instead of "____Tak".
''Illustrative samples'': [[http://www-ccrma.stanford.edu/~bosse/ castanets.wav]], [[http://anonymousriver.hp.infoseek.co.jp/castanets2/index.html castanets2.wav]]

* '''ringing''':

* '''warbling''':

* '''coarseness''':

* '''stereo collapse''':

===External links===
*[http://ff123.net/training/training.html ff123's Audio Artifact Training Page]

{{stub}}

Artifact

2006-06-10T21:01:41Z

Guruboolez: /* Different kind of artifacts */

An '''artifact''' is a noticeable difference between an uncompressed signal and a [[lossy|lossily]]-compressed copy.
[[Lossy]] encoding can result in very different kind of artifacts/distortions. Sometimes it's not easy to define why the encoding is non-transparent. There are however many typical encoding artifacts.

===Different kind of artifacts===

* '''[[pre echo]]''': pre-echo consists in a small amount of noise used to appear just before a contrasted sound events (like percussive instruments). The original transients are therefore smeared: "___shhhTak" instead of "____Tak".
''Illustrative sample'': [[http://www-ccrma.stanford.edu/~bosse/ castanets.wav]]

* '''ringing''':

* '''warbling''':

* '''coarseness''':

* '''stereo collapse''':

===External links===
*[http://ff123.net/training/training.html ff123's Audio Artifact Training Page]

{{stub}}

Artifact

2006-06-10T18:44:54Z

Guruboolez:

An '''artifact''' is a noticeable difference between an uncompressed signal and a [[lossy|lossily]]-compressed copy.
[[Lossy]] encoding can result in very different kind of artifacts/distortions. Sometimes it's not easy to define why the encoding is non-transparent. There are however many typical encoding artifacts.

===Different kind of artifacts===

* '''pre-echo''': pre-echo consists in a small amount of noise used to appear just before a contrasted sound events (like percussive instruments). The original transients are therefore smeared: "___shhhTak" instead of "____Tak".
''Illustrative sample'': castanets.wav

* '''ringing''':

* '''warbling''':

* '''coarseness''':

* '''stereo collapse''':

===External links===
*[http://ff123.net/training/training.html ff123's Audio Artifact Training Page]

{{stub}}

Choosing the best codec

2006-06-10T18:27:17Z

Guruboolez: /* Why no simple answer? */

A common question is "which format is best for me?", or "which should I use, this or that?". While these are important decisions we have all had to make at some point, there is usually no simple answer that can be given to new users.

==Why no simple answer?==

There are several factors that you must first consider, my needs aren't the same as yours, maybe we want to do different things with our music, or we have a different amount of disk space to use.

Common considerations are:
* Do you want the option of using a portable player now?
* Would no playback support other than on your PC be a problem in the future?
* Do you need to use a popular format?
* How much space do you want to use for you music?
* How much music do you want to store?
* Are you simply interested in quality?
* ''How good is your hearing''?

The last question is '''the''' most important. Why? I have poor hearing, so something that sounds good to me could well be annoying to you. Only you have your ears, so only you know what sounds good to you.

We can however make general recommendations based on test results from the entire community - for example:

; [[Lossy]] formats:
* [[MP3]] has the most widespread acceptance among the general population and in hardware players
* [[MPC]] was considered in the past as the best format for high bitrates (> 175kb/s)
* [[Ogg Vorbis]] performs very well from low to high bitrate
* [[AAC]] is the latest industry standard (MPEG) which offers excellent at every bitrate with modern encoders
* There are other lossy formats at the [[lossy|lossy page]].

; [[Lossless]] formats:
Lossless compression is the ''only'' way to retain all the original quality and lose no information.
* [[FLAC]] is considered the most widely supported format
* [[LA]] and [[OptimFrog]] is considered to be the tightest compressors
* [[WavPack]] and OptimFrog support hybrid modes, i.e. combination of lossy (for smaller files, albeit not as small as lossy formats) and lossless.
* For a list of lossless formats and their pro's and con's see the [[lossless|lossless page]].

==How can I choose for myself?==

* Listen and see, use [[ABX]]. Be aware that your tolerance can change if you train your ability to hear [[artifact]]s.
* Read the pages for the different formats and see their pro's and con's.

Winamp

2006-06-10T16:35:35Z

Guruboolez: /* Playback */

'''Winamp''' is a free music player for Windows developed by Nullsoft. A commercial "Pro" version is also available.

The main advantages of Winamp is its ease of use. In addition, it is skinnable, and extensible using plugins. As of version 5.2, it fully supports multi-user (i.e. each user of your computer may have their own skin, playlist, and other settings).

You can download Winamp at http://www.winamp.com/ . While you are there, you might also check their [http://www.winamp.com/skins/ skin library] and [http://www.winamp.com/plugins/ plugin library]. And also check the very useful [http://forums.winamp.com/ community (forums)] where new plugins are announced and publicly tested, and very minor updates (i.e. 0.001 version increment) are posted.

=== Functions ===
----
==== Free ====
* Crippled CD burning (~8x)
* Crippled CD ripping (~8x)
* AAC encoding (no MP3 encoding)
* Media library

==== Pro ====
The Pro version, which can be bought online, comes with some additional features compared to the free version.
* Burn CDs at full speed
* Rip CDs at full speed
* AAC and MP3 encoding

=== Supported formats ===
----
==== Playback ====
Directly supported formats (i.e. provided with installer) include: [[MP1]], [[MP2]], [[MP3]], [[WAV]], [[AAC]], [[WMA]], [[Ogg Vorbis]], [[MIDI]], and [[Module]]

Plugins also exist for many other formats, such as [[TTA]], [[FLAC]], [[WavPack]] and [[Musepack]]. Go to Winamp's [http://www.winamp.com/plugins/ plugin library] to download.

=== Supported languages ===
----
* English

=== Supported platforms ===
----
* Windows

=== Some recommended plugins ===
----
* '''Playlist Separator''' - provides a customizable separator line to delimit albums in a long playlist.
* '''MojoMaster''' - sexy dancer visualization.

=== External links ===
----
* [http://www.winamp.com Winamp: Homepage]

* [http://winamp.com/player/ Winamp: Download]

* [http://winamp.com/about/story.php More information]

{{stub}}

Topic Index

2006-06-10T15:50:22Z

Guruboolez: /* General Guides */

* Please see [http://www.hydrogenaudio.org/forums/index.php?showtopic=12979&st=25&p=247441&#entry247441 this thread] for a discussion of the future structure of this wiki. If you have thoughts, comments, suggestions, etc., please join in this discussion. In the meantime, please feel free to fill in gaps in the information below.
* See also [http://www.hydrogenaudio.org/forums/index.php?showtopic=28658 style related discussion]

=General Information=

==General Guides==
* [[Create a long-term archive]]
* [[Enabling DMA]]
* [[Audio_format_guide]]

==EAC Guides==
* [[Create a lossless back-up with EAC and Flac]]
* [[EAC and Lame | Configuring EAC and Lame]]
* [[EAC_and_Ogg_Vorbis | Configuring EAC and Vorbis]]
* [[EAC_and_WavPack | Configuring EAC and Wavpack]]
* [[EAC_and_Flac | Configuring EAC and FLAC]]
* [[EAC_and_Monkeys_Audio | Configuring EAC and Monkey's Audio]]

==CDex Guides==
==MP3 Guides==

* [http://wiki.hydrogenaudio.org/index.php?title=LAME Recommended settings for encoding with LAME]

==Ogg Vorbis Guides==

* [http://wiki.hydrogenaudio.org/index.php?title=Recommended_Ogg_Vorbis Recommended encoders and settings for encoding with Vorbis].

=Audio Codecs=

==[[Lossy]]==
*[[AAC]]
*[[AC3]]
*[[ATRAC3]]
*[[DTS]]
*[[MP2]]
*[[MP3]]
*[[Musepack]]
*[[Ogg Vorbis]]
*[[QDesign]]
*[[VQF]]
*[[WMA]]

==[[Lossless]]==

*[[ALAC|Apple Lossless]]
*[[FLAC|Free Lossless Audio Compressor]]
*[[LA|Lossless Audio]]
*[[LPAC]]
*[[Monkey's Audio]]
*[[OptimFROG]]
*[[RealAudio Lossless]]
*[[Shorten]]
*[[TTA|True Audio]]
*[[WavPack]]
*[[WMA|WMA Lossless]]

=[[Metadata]] (Tags)=
* [[APEv1]]
* [[APEv2]]
* [[ID3v1]]
* [[ID3v1.1]]
* [[ID3v2]]
* [[Vorbis Comment]]

=Media Extractors=

==CD Extractors==

* [[CDex]] (Win32)
* [[cdparanoia]] (Posix)
* [[dBpowerAMP with AccurateRip]] (Win32)
* [[Exact_Audio_Copy|Exact Audio Copy]] (Win32)
* [[Grip]] (Posix)
* [[iTunes]] (Win32/OSX)
* [[MediaMonkey]] (Win32)
* [[Max]] (OSX)
* [[PlexTools]] (Win32)
* [[Rubyripper]] (Posix/OSX)

==DVD Extractors==
* [http://pessoal.onda.com.br/rjamorim/SetupDVDDecrypter_3.5.4.0.exe DVD Decrypter] (Win32)

=Media Players=

== Windows ==

* [[Apollo]]
* [[dBpowerAMP]]
* [[Foobar2000:Foobar2000|foobar2000]]
* [[iTunes]]
* [[MediaMonkey]]
* [[musikCube]]
* [[Quintessential Player]]
* [[VUplayer]]
* [[Winamp]]
* [[Windows Media Player]]
* [[wxMusik]]
* [[XMPlay]]

==Linux/BSD==

* [[Amarok]]
* [[BMP]]
* [[JuK]]
* [[LAMIP]]
* [[Muine]]
* [[Music Player Daemon (MPD)]]
* [[Quod Libet]]
* [[Rhythmbox]]
* [[wxMusik]]
* [[XMMS]]

==Mac OS X (Non-BSD Specific) ==

* [[iTunes]]
* [[skiTunes]]
* [[Whamb]]

==Other==

* [[CL-Amp]] (BeOS)

=Audio Editors=

==Windows==

* [[Adobe_Audition|Adobe Audition]] (Previously known as Cool Edit)
* [[Audacity]]
* [[Goldwave]]
* [http://www.sonymediasoftware.com/products/soundforgefamily.asp Sony Sound Forge] (Previously released by Sonic Foundry)

==Linux/BSD==

* [[Audacity]]
* [[ReZound]]

==Mac OS X (Non-BSD Specific) ==

* [[Audacity]]

==Other==

* [http://timidity.sourceforge.net/ Timidity++] (MIDI to PCM (WAV) converter) Timidity++ synthesizes MIDI files (sequences) in real-time using Gravis UltraSound Soundfont patches (loosly based upon Wavetable Synthesis) to common digital audio file formats such as, WAV, AU, AIFF, Ogg Vorbis, FLAC, etc. Useful for those who want to bypass FM Synthesizers on their sound card's to hear MIDI sequence as it was intended to be heard.)

=Testing Software=

==Subjective Perceptual==

* [[ABC/HR]]
* [[PCABX]]

==Objective==

''Note: Might be good to put something here about the problems of quality comparisons using graphs, frequency sweeps, etc.''

* [[EAQUAL]]
* [[Rightmark_Audio_Analyzer|Rightmark Audio Analyzer]]

=Audio Hardware=

==PC Audio==

*[[Terratec EWX 24/96]]
*[[M-Audio Audiophile 24/96]]
*[[M-Audio Revolution 5.1]]
*[[M-Audio Revolution 7.1]]
*[[Chaintech AV-710]]
*[[Audiotrak MAYA 5.1]]
*[[Audiotrak Prodigy 7.1]]

==Notebook Audio==
*[[Echo Indigo IO 24/96]]

==HiFi==
* [[M-Audio Fast Track USB]]

==Digital Audio Players==

'''Portable Flash'''

''(These players make use of a internal flash drive.)''

* [[Apple iPod]] Nano
* [[Apple iPod]] Shuffle
* [[Creative MuVo]]
* [[iRiver iFP Series]]
* [[MPIO lFP Series]]
* [[Rio Carbon]]
* [[Neuros]]

'''Portable HD'''

''(These players make use of a internal harddrive.)''

* [[Apple iPod]] with ''([http://www.rockbox.org/twiki/bin/view/Main/TargetStatus#iriver_H110_H115_H120_H140 Rockbox firmware])''
* [[Archos Jukebox with Rockbox Software]]
* [[iAudio M3]]
* [[iRiver H-Series]] with ''([http://www.rockbox.org/twiki/bin/view/Main/TargetStatus#iriver_H110_H115_H120_H140 Rockbox firmware])''
* [[MPIO H-Series]]
* [[Neuros]]
* [[Rio Karma]]

'''Portable CD'''

'''Car Players'''

''(Car stereos that can read MP3, Vorbis, WMA, etc.).''

* [[Aiwa CDC-MP3]]
* [[Yakumo Ultrasound]]

=Audio Theory=

==Analog Audio==
* [[Tube Amplifiers]]
* [[Vinyl_Playback_and_Recording|Vinyl Audio]]

==Digital Audio==
* [[Solid State Amplifiers]]
* [[Replaygain]]

==Testing Methodology==

* [[ABX]]
* [[EAQUAL]]

=Audio Development=

==Getting Started==
''note: Let's start with basic development tools (compilers, engineering tools, dev. libraries) until we think of more tools to add. I am also adding external links to books, tutorials, etc under resources.''

==Tools==

* [http://www.mathworks.com/products/matlab/ MATLAB 7.0] commercial software for algorithmic design, developement, engineering, and scientific computing. (multi-platform support)
* [http://www.octave.org/ GNU Octave] open-source alternative software (GPL) to MATLAB for numerical computations, engineering, and scientific computing. (multi-platform support)
* [http://www.fftw.org/ FFTW] Is a C subroutine library for computing the Discrete Fourier transform (DFT) in one or more dimensions on real and complex inputs.
* [http://gcc.gnu.org/ GCC] THE GNU compiler collection for C, C++, Objective-C, Fortran, Java, and Ada.
* [http://www.gnu.org/software/emacs/emacs.html GNU Emacs] an extensible, customizable, self-documenting real-time display editor. Great for writing all types of source code especially on Unix. (multi-platform support)
* [http://www.bloodshed.net/devcpp.html DevCPP] free front-end IDE and compiler for the C and C++ languages. Delphi and C source code available. (Win 9x, NT, 2000, and XP)

==Resources==

* [http://www.hydrogenaudio.org/forums/index.php?showforum=30 Scientific/R&D Forums] for Psychoacoustic, DSP, Electrical Engineering, theory, and coding related questions. (most questions are generally answered)
* [http://www.aes.org/ AES] The Audio Engineering Society website. Home of year-round world AES conferences.
* [http://www.dspguru.com/info/books/favor.htm DSP Tutorials] this site provides another good introduction in to the area of DSP.
* [http://www.musicdsp.org/archive.php?classid=2 Music-DSP] source-code archive for anaylsis, filters, effects and synthesis. (C, C++, and Java code)
* [http://www.gamedev.net/reference/articles/article2008.asp OpenAL] a beginners tutorial on writing code using OpenAL for audio programming in computer games and other applications. (C, C++).
* [http://www.alsa-project.org/ ALSA Project] (Advanced Linux Sound Architecture) bringing audio and MIDI capabilities to Linux.
* [http://www.engmath.dal.ca/courses/engm6610/notes/notes.html A Really friendly guide to Wavelets] A good introduction to wavelets aimed towards engineer, requires a fair amount of background knowledge.

==Books/Research==
* [http://www.amazon.com/gp/product/3540231595/qid=1135380559/sr=1-3/ref=sr_1_3/102-1730075-7300931?s=books&v=glance&n=283155 Psychoacoustics - Facts and Models] author's Zwicker, Fastl, and Hugo, revised 2005 third edition. The book for comprehensive psychoacoustics models and figures.
* [http://www.eas.asu.edu/~spanias/papers/paper-audio-tedspanias-00.pdf Perceptual Audio Coding] authors A. Painter and T. Spanias. A comprehensive paper on percepual audio coding (PDF)
* [http://www.amazon.com/gp/product/0780334493/103-2094923-9567001?v=glance&n=283155&%5Fencoding=UTF8&me=ATVPDKIKX0DER&no=283155&st=books Speech Communications Human and Machine] this book provides a good introduction to speech coding, inlcuding anaylsis, recognition, and perception. This text is a very good introduction for beginners.
* [http://www.dspguide.com/ Scientist and Engineer's Guide to DSP] author Steve Smith, a great guide for beginners new to the subject of DSP (free online text)
*[http://www.amazon.com/exec/obidos/tg/detail/-/0792391810/ref=ase_theinternetdatac/103-9882844-5344648?v=glance&s=books Vector Quantization] authors Gersho and Gray. Good read for understanding how VQ and arithmetic coding work.

=Audio Resources=

==Websites==

''Note: Let's include a small description to the side for now, so that we have something to work with when this section becomes large enough for its own page''

* http://www.audiocoding.com (Page with a wiki on technical audio topics, homepage of FAAC and FAAD2, also has an AAC forum.)
* http://www.ff123.net (Lots of general information on various MP3 implementations, test samples, testing methodology information, homepage of ABC/HR)
* http://www.head-fi.org (general information/board about head phones and portable audio players)
* http://www.rarewares.org (Downloads for many audio and media tools)
* http://www.rockbox.org/ (Open-source jukebox firmware for numerous DAP and architectures, GNU/GPL Liscense).
* http://psplab.csie.nctu.edu.tw/invboard2_0/index.php (Perceptual Signal Processing Lab, small university forum based in Tawain dealing with perceptual coding on acedemic level).

==Articles/Debates==
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=31759&st=0 DVD-A vs. SACD debate]
* [http://www.ambisonic.net/pdf/ambidvd2001.pdf 5.1 surround vs. Ambisonics debate]
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=38041&st=0 Subjective vs. Objective testing]

==Listening Tests==
* [http://www.rjamorim.com/test/ Roberto's listening tests]
* [[Listening_Tests|Inventory of several listening tests, mainly on HA.org]]

=Other Topics=

==Video==

* [[MPEG-4 Visual]]
* [[Real Video]]
* [[Theora]]
* [[VP6]]
* [[Windows Media Video]]

==[[Container format]]s==
* [[ASF]]
* [[AVI]]
* [[Matroska]]
* [[MOV]]
* [[MP4]]
* [[Ogg]]

=Glossary=

* [[Glossary_Of_Audio_Terms|Glossary of Audio Terms]]

Topic Index

2006-06-10T15:45:24Z

Guruboolez: /* Listening Tests */

* Please see [http://www.hydrogenaudio.org/forums/index.php?showtopic=12979&st=25&p=247441&#entry247441 this thread] for a discussion of the future structure of this wiki. If you have thoughts, comments, suggestions, etc., please join in this discussion. In the meantime, please feel free to fill in gaps in the information below.
* See also [http://www.hydrogenaudio.org/forums/index.php?showtopic=28658 style related discussion]

=General Information=

==General Guides==
* [[Create a long-term archive]]
* [[Enabling DMA]]
==EAC Guides==
* [[Create a lossless back-up with EAC and Flac]]
* [[EAC and Lame | Configuring EAC and Lame]]
* [[EAC_and_Ogg_Vorbis | Configuring EAC and Vorbis]]
* [[EAC_and_WavPack | Configuring EAC and Wavpack]]
* [[EAC_and_Flac | Configuring EAC and FLAC]]
* [[EAC_and_Monkeys_Audio | Configuring EAC and Monkey's Audio]]

==CDex Guides==
==MP3 Guides==

* [http://wiki.hydrogenaudio.org/index.php?title=LAME Recommended settings for encoding with LAME]

==Ogg Vorbis Guides==

* [http://wiki.hydrogenaudio.org/index.php?title=Recommended_Ogg_Vorbis Recommended encoders and settings for encoding with Vorbis].

=Audio Codecs=

==[[Lossy]]==
*[[AAC]]
*[[AC3]]
*[[ATRAC3]]
*[[DTS]]
*[[MP2]]
*[[MP3]]
*[[Musepack]]
*[[Ogg Vorbis]]
*[[QDesign]]
*[[VQF]]
*[[WMA]]

==[[Lossless]]==

*[[ALAC|Apple Lossless]]
*[[FLAC|Free Lossless Audio Compressor]]
*[[LA|Lossless Audio]]
*[[LPAC]]
*[[Monkey's Audio]]
*[[OptimFROG]]
*[[RealAudio Lossless]]
*[[Shorten]]
*[[TTA|True Audio]]
*[[WavPack]]
*[[WMA|WMA Lossless]]

=[[Metadata]] (Tags)=
* [[APEv1]]
* [[APEv2]]
* [[ID3v1]]
* [[ID3v1.1]]
* [[ID3v2]]
* [[Vorbis Comment]]

=Media Extractors=

==CD Extractors==

* [[CDex]] (Win32)
* [[cdparanoia]] (Posix)
* [[dBpowerAMP with AccurateRip]] (Win32)
* [[Exact_Audio_Copy|Exact Audio Copy]] (Win32)
* [[Grip]] (Posix)
* [[iTunes]] (Win32/OSX)
* [[MediaMonkey]] (Win32)
* [[Max]] (OSX)
* [[PlexTools]] (Win32)
* [[Rubyripper]] (Posix/OSX)

==DVD Extractors==
* [http://pessoal.onda.com.br/rjamorim/SetupDVDDecrypter_3.5.4.0.exe DVD Decrypter] (Win32)

=Media Players=

== Windows ==

* [[Apollo]]
* [[dBpowerAMP]]
* [[Foobar2000:Foobar2000|foobar2000]]
* [[iTunes]]
* [[MediaMonkey]]
* [[musikCube]]
* [[Quintessential Player]]
* [[VUplayer]]
* [[Winamp]]
* [[Windows Media Player]]
* [[wxMusik]]
* [[XMPlay]]

==Linux/BSD==

* [[Amarok]]
* [[BMP]]
* [[JuK]]
* [[LAMIP]]
* [[Muine]]
* [[Music Player Daemon (MPD)]]
* [[Quod Libet]]
* [[Rhythmbox]]
* [[wxMusik]]
* [[XMMS]]

==Mac OS X (Non-BSD Specific) ==

* [[iTunes]]
* [[skiTunes]]
* [[Whamb]]

==Other==

* [[CL-Amp]] (BeOS)

=Audio Editors=

==Windows==

* [[Adobe_Audition|Adobe Audition]] (Previously known as Cool Edit)
* [[Audacity]]
* [[Goldwave]]
* [http://www.sonymediasoftware.com/products/soundforgefamily.asp Sony Sound Forge] (Previously released by Sonic Foundry)

==Linux/BSD==

* [[Audacity]]
* [[ReZound]]

==Mac OS X (Non-BSD Specific) ==

* [[Audacity]]

==Other==

* [http://timidity.sourceforge.net/ Timidity++] (MIDI to PCM (WAV) converter) Timidity++ synthesizes MIDI files (sequences) in real-time using Gravis UltraSound Soundfont patches (loosly based upon Wavetable Synthesis) to common digital audio file formats such as, WAV, AU, AIFF, Ogg Vorbis, FLAC, etc. Useful for those who want to bypass FM Synthesizers on their sound card's to hear MIDI sequence as it was intended to be heard.)

=Testing Software=

==Subjective Perceptual==

* [[ABC/HR]]
* [[PCABX]]

==Objective==

''Note: Might be good to put something here about the problems of quality comparisons using graphs, frequency sweeps, etc.''

* [[EAQUAL]]
* [[Rightmark_Audio_Analyzer|Rightmark Audio Analyzer]]

=Audio Hardware=

==PC Audio==

*[[Terratec EWX 24/96]]
*[[M-Audio Audiophile 24/96]]
*[[M-Audio Revolution 5.1]]
*[[M-Audio Revolution 7.1]]
*[[Chaintech AV-710]]
*[[Audiotrak MAYA 5.1]]
*[[Audiotrak Prodigy 7.1]]

==Notebook Audio==
*[[Echo Indigo IO 24/96]]

==HiFi==
* [[M-Audio Fast Track USB]]

==Digital Audio Players==

'''Portable Flash'''

''(These players make use of a internal flash drive.)''

* [[Apple iPod]] Nano
* [[Apple iPod]] Shuffle
* [[Creative MuVo]]
* [[iRiver iFP Series]]
* [[MPIO lFP Series]]
* [[Rio Carbon]]
* [[Neuros]]

'''Portable HD'''

''(These players make use of a internal harddrive.)''

* [[Apple iPod]] with ''([http://www.rockbox.org/twiki/bin/view/Main/TargetStatus#iriver_H110_H115_H120_H140 Rockbox firmware])''
* [[Archos Jukebox with Rockbox Software]]
* [[iAudio M3]]
* [[iRiver H-Series]] with ''([http://www.rockbox.org/twiki/bin/view/Main/TargetStatus#iriver_H110_H115_H120_H140 Rockbox firmware])''
* [[MPIO H-Series]]
* [[Neuros]]
* [[Rio Karma]]

'''Portable CD'''

'''Car Players'''

''(Car stereos that can read MP3, Vorbis, WMA, etc.).''

* [[Aiwa CDC-MP3]]
* [[Yakumo Ultrasound]]

=Audio Theory=

==Analog Audio==
* [[Tube Amplifiers]]
* [[Vinyl_Playback_and_Recording|Vinyl Audio]]

==Digital Audio==
* [[Solid State Amplifiers]]
* [[Replaygain]]

==Testing Methodology==

* [[ABX]]
* [[EAQUAL]]

=Audio Development=

==Getting Started==
''note: Let's start with basic development tools (compilers, engineering tools, dev. libraries) until we think of more tools to add. I am also adding external links to books, tutorials, etc under resources.''

==Tools==

* [http://www.mathworks.com/products/matlab/ MATLAB 7.0] commercial software for algorithmic design, developement, engineering, and scientific computing. (multi-platform support)
* [http://www.octave.org/ GNU Octave] open-source alternative software (GPL) to MATLAB for numerical computations, engineering, and scientific computing. (multi-platform support)
* [http://www.fftw.org/ FFTW] Is a C subroutine library for computing the Discrete Fourier transform (DFT) in one or more dimensions on real and complex inputs.
* [http://gcc.gnu.org/ GCC] THE GNU compiler collection for C, C++, Objective-C, Fortran, Java, and Ada.
* [http://www.gnu.org/software/emacs/emacs.html GNU Emacs] an extensible, customizable, self-documenting real-time display editor. Great for writing all types of source code especially on Unix. (multi-platform support)
* [http://www.bloodshed.net/devcpp.html DevCPP] free front-end IDE and compiler for the C and C++ languages. Delphi and C source code available. (Win 9x, NT, 2000, and XP)

==Resources==

* [http://www.hydrogenaudio.org/forums/index.php?showforum=30 Scientific/R&D Forums] for Psychoacoustic, DSP, Electrical Engineering, theory, and coding related questions. (most questions are generally answered)
* [http://www.aes.org/ AES] The Audio Engineering Society website. Home of year-round world AES conferences.
* [http://www.dspguru.com/info/books/favor.htm DSP Tutorials] this site provides another good introduction in to the area of DSP.
* [http://www.musicdsp.org/archive.php?classid=2 Music-DSP] source-code archive for anaylsis, filters, effects and synthesis. (C, C++, and Java code)
* [http://www.gamedev.net/reference/articles/article2008.asp OpenAL] a beginners tutorial on writing code using OpenAL for audio programming in computer games and other applications. (C, C++).
* [http://www.alsa-project.org/ ALSA Project] (Advanced Linux Sound Architecture) bringing audio and MIDI capabilities to Linux.
* [http://www.engmath.dal.ca/courses/engm6610/notes/notes.html A Really friendly guide to Wavelets] A good introduction to wavelets aimed towards engineer, requires a fair amount of background knowledge.

==Books/Research==
* [http://www.amazon.com/gp/product/3540231595/qid=1135380559/sr=1-3/ref=sr_1_3/102-1730075-7300931?s=books&v=glance&n=283155 Psychoacoustics - Facts and Models] author's Zwicker, Fastl, and Hugo, revised 2005 third edition. The book for comprehensive psychoacoustics models and figures.
* [http://www.eas.asu.edu/~spanias/papers/paper-audio-tedspanias-00.pdf Perceptual Audio Coding] authors A. Painter and T. Spanias. A comprehensive paper on percepual audio coding (PDF)
* [http://www.amazon.com/gp/product/0780334493/103-2094923-9567001?v=glance&n=283155&%5Fencoding=UTF8&me=ATVPDKIKX0DER&no=283155&st=books Speech Communications Human and Machine] this book provides a good introduction to speech coding, inlcuding anaylsis, recognition, and perception. This text is a very good introduction for beginners.
* [http://www.dspguide.com/ Scientist and Engineer's Guide to DSP] author Steve Smith, a great guide for beginners new to the subject of DSP (free online text)
*[http://www.amazon.com/exec/obidos/tg/detail/-/0792391810/ref=ase_theinternetdatac/103-9882844-5344648?v=glance&s=books Vector Quantization] authors Gersho and Gray. Good read for understanding how VQ and arithmetic coding work.

=Audio Resources=

==Websites==

''Note: Let's include a small description to the side for now, so that we have something to work with when this section becomes large enough for its own page''

* http://www.audiocoding.com (Page with a wiki on technical audio topics, homepage of FAAC and FAAD2, also has an AAC forum.)
* http://www.ff123.net (Lots of general information on various MP3 implementations, test samples, testing methodology information, homepage of ABC/HR)
* http://www.head-fi.org (general information/board about head phones and portable audio players)
* http://www.rarewares.org (Downloads for many audio and media tools)
* http://www.rockbox.org/ (Open-source jukebox firmware for numerous DAP and architectures, GNU/GPL Liscense).
* http://psplab.csie.nctu.edu.tw/invboard2_0/index.php (Perceptual Signal Processing Lab, small university forum based in Tawain dealing with perceptual coding on acedemic level).

==Articles/Debates==
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=31759&st=0 DVD-A vs. SACD debate]
* [http://www.ambisonic.net/pdf/ambidvd2001.pdf 5.1 surround vs. Ambisonics debate]
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=38041&st=0 Subjective vs. Objective testing]

==Listening Tests==
* [http://www.rjamorim.com/test/ Roberto's listening tests]
* [[Listening_Tests|Inventory of several listening tests, mainly on HA.org]]

=Other Topics=

==Video==

* [[MPEG-4 Visual]]
* [[Real Video]]
* [[Theora]]
* [[VP6]]
* [[Windows Media Video]]

==[[Container format]]s==
* [[ASF]]
* [[AVI]]
* [[Matroska]]
* [[MOV]]
* [[MP4]]
* [[Ogg]]

=Glossary=

* [[Glossary_Of_Audio_Terms|Glossary of Audio Terms]]

Talk:Musepack

2006-05-28T11:17:28Z

Guruboolez:

Hello... what happened to the long information on MPC?
--[[User:Pepoluan|pepoluan]] 23:37, 4 January 2006 (CST)

----
''"Informal listening tests have demonstrated that MPC is the best [[lossy]] audio encoder at ~140kbps and above [[bitrate]]s,"''
I removed this sentence, according to TOS#8 that requires from any member to provide proofs for quality claims. There are no links for "informal listening tests (...) at ~140 kbps and above" demonstrating any MPC superiority (but only two multiformat 128 kbps listening tests showing that MPC is tied with AAC, Vorbis and WMAPro).

----
"designed to be transparent at defaut setting": according to current MPC developers it isn't true ([http://www.hydrogenaudio.org/forums/index.php?s=&showtopic=34924&view=findpost&p=306949 link No.1] and [http://www.musepack.net/forum/viewtopic.php?p=1008#1008 link No.2])

Talk:Musepack

2006-05-28T11:17:09Z

Guruboolez:

Hello... what happened to the long information on MPC?
--[[User:Pepoluan|pepoluan]] 23:37, 4 January 2006 (CST)

----
''"Informal listening tests have demonstrated that MPC is the best [[lossy]] audio encoder at ~140kbps and above [[bitrate]]s,"''
I removed this sentence, according to TOS#8 that requires from any member to provide proofs for quality claims. There are no links for "informal listening tests (...) at ~140 kbps and above" demonstrating any MPC superiority (but only two multiformat 128 kbps listening tests showing that MPC is tied with AAC, Vorbis and WMAPro).

----
"designed to be transparent at defaut setting": according to current MPC developers it isn't true ([http://www.hydrogenaudio.org/forums/index.php?s=&showtopic=34924&view=findpost&p=306949 link No.1] and [URL=http://www.musepack.net/forum/viewtopic.php?p=1008#1008 link No.2])

Musepack

2006-05-28T11:05:34Z

Guruboolez: /* Pros */

=Introduction=
'''Musepack''' is a lossy audio compression scheme created by [[Andree Buschmann]]. It is strongly based on the [[MPEG-1]] Layer-2 ([[MP2]]) algorithms. The format doesn't compete well at lower, 'streaming' bitrates such as 32/48/64kbps. This is due to MPC being a [[subband]] [[codec]] as well as the fact that very little optimization has gone into such low [[bitrate]]s. As can be seen in various 128kbit/s listening tests (see below), despite the fact that MPC has been optimized little for such bitrates it is in the same class of other modern competitors such as [[AAC]] and [[Ogg Vorbis]].

==Pros==
* Suffers from different "problem cases" than most other formats (less pre-echo)
* Very fast encoding/decoding
* Designed to be very good by default at --standard setting.
* Open source encoder
* Portable playback by Pocket-PCs, Palm OS-based and Windows CE/Windows Mobile-based devices, even Smartphones, see http://tcpmp.corecodec.org
* Portable playback on iRiver h1x0 and Archos Gmini players, see http://www.rockbox.org
* Support & development forum at http://www.Musepack.net

==Cons==
* Marginal support (yet) on portable players
* No [[multichannel]]
* No specification available
* Seeking is imperfect (to be fixed in SV7.5)
* Not streamable
* Can't be cut/edited
* No support for [[sampling rate]]s above 48khz

=Technical details=
==Supported input formats (SV7)==
* channels: 1 or 2
* bit depths: 1 to 32 bit linear [[PCM]]
* sample rates: 32kHz, 37.8kHz, 44.1kHz, 48kHz (44.1 and 48 are highly tuned)
* [[WAV]], raw [[PCM]], a lot of [[lossless]] compressed audio formats like [[FLAC]], [[LPAC]], [[Monkey's_Audio|APE]], [[OptimFROG]], [[SZIP]] and Shorten ([[SHN]])

==Encoder Functions==
[[MPC Encoder Functions]]

=Links=
==User oriented links==
* [http://musepack.net Musepack.net] - a general info, news and software site.
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=1927 Users' HowTo MPC guide at HydrogenAudio]
* [[Case]]'s [http://www.saunalahti.fi/~cse/ page] (Winamp plug-ins and more).
* [[Frank Klemm]]'s [http://www.uni-jena.de/~pfk/mpp/ official page (out of order now)]
* Mirrored at: http://hydrogenaudio.org/musepack/klemm/www.personal.uni-jena.de/~pfk/mpp/
* [http://betaplayer.corecodec.org/ BetaPlayer], the first Musepack-able player on PocketPCs

==Technical links==
* [[Frank Klemm]]'s [http://www.uni-jena.de/~pfk/mpp/ official page]
* [http://www.audiocoding.com/modules/wiki/?page=MPC MPC at AudioCodingWiki]
* [http://www.caddr.com/code/libmusepack libmusepack portable musepack decoding library (in progress)]

==Listening test involving MPC==
* [[Listening Tests]] page
* [http://ff123.net/128tests.html ff123's 128kbit/s group listening test]
* [http://ff123.net/128test/instruct.html ff123's second 128kbit/s group listening test]
* [http://audio.ciara.us/test/128extension/results.html rjamorim's 128kbit/s test]

Please note that some of these tests, while valid, used versions of the encoders in almost all of the formats tested which have now been superseded. You should make your own decision about the comparative quality of MPC, listening to clips of music in the style you prefer.

Also note that these are tests at low bitrates; an area where MPC is not particularly optimized. The encoder was designed by the author to be transparent at the --standard setting, thus little to no low [[bitrate]] tuning has gone into the [[codec]], opposite to that of [[AAC]], [[Ogg Vorbis]], [[WMA]] and others which focus more on this region. However, as can be seen in the various listening test pages, MPC competes surprisingly well with the rest of them.

Talk:Musepack

2006-05-28T11:04:04Z

Guruboolez:

Musepack

2006-05-28T11:00:41Z

Guruboolez: /* Introduction */

=Introduction=
'''Musepack''' is a lossy audio compression scheme created by [[Andree Buschmann]]. It is strongly based on the [[MPEG-1]] Layer-2 ([[MP2]]) algorithms. The format doesn't compete well at lower, 'streaming' bitrates such as 32/48/64kbps. This is due to MPC being a [[subband]] [[codec]] as well as the fact that very little optimization has gone into such low [[bitrate]]s. As can be seen in various 128kbit/s listening tests (see below), despite the fact that MPC has been optimized little for such bitrates it is in the same class of other modern competitors such as [[AAC]] and [[Ogg Vorbis]].

==Pros==
* Best [[lossy]] encoder for mid-high bitrates
* Suffers from far less "problem cases" than other formats.
* Very fast encoding/decoding
* Designed to be [[transparency|transparent]] by default at --standard setting.
* Open source encoder
* Portable playback by Pocket-PCs, Palm OS-based and Windows CE/Windows Mobile-based devices, even Smartphones, see http://tcpmp.corecodec.org
* Portable playback on iRiver h1x0 and Archos Gmini players, see http://www.rockbox.org
* Support & development forum at http://www.Musepack.net

==Cons==
* Marginal support (yet) on portable players
* No [[multichannel]]
* No specification available
* Seeking is imperfect (to be fixed in SV7.5)
* Not streamable
* Can't be cut/edited
* No support for [[sampling rate]]s above 48khz

=Technical details=
==Supported input formats (SV7)==
* channels: 1 or 2
* bit depths: 1 to 32 bit linear [[PCM]]
* sample rates: 32kHz, 37.8kHz, 44.1kHz, 48kHz (44.1 and 48 are highly tuned)
* [[WAV]], raw [[PCM]], a lot of [[lossless]] compressed audio formats like [[FLAC]], [[LPAC]], [[Monkey's_Audio|APE]], [[OptimFROG]], [[SZIP]] and Shorten ([[SHN]])

==Encoder Functions==
[[MPC Encoder Functions]]

=Links=
==User oriented links==
* [http://musepack.net Musepack.net] - a general info, news and software site.
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=1927 Users' HowTo MPC guide at HydrogenAudio]
* [[Case]]'s [http://www.saunalahti.fi/~cse/ page] (Winamp plug-ins and more).
* [[Frank Klemm]]'s [http://www.uni-jena.de/~pfk/mpp/ official page (out of order now)]
* Mirrored at: http://hydrogenaudio.org/musepack/klemm/www.personal.uni-jena.de/~pfk/mpp/
* [http://betaplayer.corecodec.org/ BetaPlayer], the first Musepack-able player on PocketPCs

==Technical links==
* [[Frank Klemm]]'s [http://www.uni-jena.de/~pfk/mpp/ official page]
* [http://www.audiocoding.com/modules/wiki/?page=MPC MPC at AudioCodingWiki]
* [http://www.caddr.com/code/libmusepack libmusepack portable musepack decoding library (in progress)]

==Listening test involving MPC==
* [[Listening Tests]] page
* [http://ff123.net/128tests.html ff123's 128kbit/s group listening test]
* [http://ff123.net/128test/instruct.html ff123's second 128kbit/s group listening test]
* [http://audio.ciara.us/test/128extension/results.html rjamorim's 128kbit/s test]

Please note that some of these tests, while valid, used versions of the encoders in almost all of the formats tested which have now been superseded. You should make your own decision about the comparative quality of MPC, listening to clips of music in the style you prefer.

Also note that these are tests at low bitrates; an area where MPC is not particularly optimized. The encoder was designed by the author to be transparent at the --standard setting, thus little to no low [[bitrate]] tuning has gone into the [[codec]], opposite to that of [[AAC]], [[Ogg Vorbis]], [[WMA]] and others which focus more on this region. However, as can be seen in the various listening test pages, MPC competes surprisingly well with the rest of them.

Talk:Choosing the best codec

2006-05-28T10:57:20Z

Guruboolez:

MPC was never considered superior to other formats at ~128 kbps. To the great surprise of the community it got the best mark on the first [http://www.rjamorim.com/test/128extension/results.html Multiformat listening test] but was still statistically tied to AAC, Vorbis and WMAPro. On the [http://www.rjamorim.com/test/multiformat128/results.html Second multiformat listening test] MPC didn't got the best mark and was still tied to Vorbis and AAC.
Musepack was considered by "audiophiles" as the best lossy format for high bitrates (from --standard or 175 kbps and more). It may be worth mentionning that '''no trace''' of any listening test proving this superiority could be found on the web. With recent developments of AAC (iTunes and Nero Digital) and Vorbis (aoTuV) the superiority of MPC at high bitrate is really unlikely.

Talk:Choosing the best codec

2006-05-28T10:53:26Z

Guruboolez:

MPC was never considered superior to other formats at ~128 kbps. It got the best mark on the first [http://www.rjamorim.com/test/128extension/results.html Multiformat listening test] but was still statistically tied to AAC, Vorbis and WMAPro. On the [http://www.rjamorim.com/test/multiformat128/results.html Second multiformat listening test] MPC didn't got the best mark and was still tied to Vorbis and AAC.
Musepack was considered by "audiophiles" as the best lossy format for high bitrates (from --standard or 175 kbps and more). It may be worth mentionning that '''no trace''' of any listening test proving this superiority could be found on the web. With recent developments of AAC (iTunes and Nero Digital) and Vorbis (aoTuV) the superiority of MPC at high bitrate is really unlikely.

Choosing the best codec

2006-05-28T10:43:41Z

Guruboolez: /* Why no simple answer? */

A common question is "which format is best for me?", or "which should I use, this or that?". While these are important decisions we have all had to make at some point, there is usually no simple answer that can be given to new users.

==Why no simple answer?==

There are several factors that you must first consider, my needs aren't the same as yours, maybe we want to do different things with our music, or we have a different amount of disk space to use.

Common considerations are:
* Do you want the option of using a portable player now?
* Would no playback support other than on your PC be a problem in the future?
* Do you need to use a popular format?
* How much space do you want to use for you music?
* How much music do you want to store?
* Are you simply interested in quality?
* ''How good is your hearing''?

The last question is '''the''' most important. Why? I have poor hearing, so something that sounds good to me could well be annoying to you. Only you have your ears, so only you know what sounds good to you.

We can however make general recommendations based on test results from the entire community - for example:

; [[Lossy]] formats:
* [[MP3]] is has the most widespread acceptance among the general population and in hardware players
* [[MPC]] was considered in the past as the best format for high bitrates (> 175kb/s)
* [[Ogg Vorbis]] and [[AAC]] HE are thought to perform better than others at low bitrates (< 128kb/s)
* There are other lossy formats at the [[lossy|lossy page]].

; [[Lossless]] formats:
Lossless compression is the ''only'' way to retain all the original quality and lose no information.
* [[FLAC]] is considered the most widely supported format
* [[LA]] and [[OptimFrog]] is considered to be the tightest compressors
* [[WavPack]] and OptimFrog support hybrid modes, i.e. combination of lossy (for smaller files, albeit not as small as lossy formats) and lossless.
* For a list of lossless formats and their pro's and con's see the [[lossless|lossless page]].

==How can I choose for myself?==

* Listen and see, use [[ABX]]. Be aware that your tolerance can change if you train your ability to hear [[artifact]]s.
* Read the pages for the different formats and see their pro's and con's.

Advanced Audio Coding

2006-05-28T10:40:11Z

Guruboolez: /* Pros */

==Introduction==
'''AAC''' or 'Advanced Audio Coding' forms part of the latest specifications from the MPEG committee, and is their official successor to the popular [[MP3]] format. As with MP3, the AAC format is an international standard, and is backed by several big-name companies, including Dolby, Sony and Nokia.

With the 13 years that had passed since the creation of the MP3 format, many improvements had been realised leading to a seemingly complex specification with several flavours of AAC available. To potentially add to the confusion, AAC is usually wrapped inside an [[MP4]] container to provide tagging, seeking and possibly other benefits?? For this reason, AAC can also be referred to as MP4 audio..

There are several AAC encoders to choose from, coming from large names such as Apple ([[iTunes]]) , Real Networks and Nero AG (Creators of Nero Burning Rom), or the open source [http://www.audiocoding.com FAAC] which is analogous to the [[LAME]] encoder. AAC is supported on some hardware players, most notably the [[Apple iPod]] and some cell phones, and is available in Apple's online store.

In terms of quality, the AAC format is on par with [[Ogg Vorbis]], [[LAME]] MP3, [[WMA]] Pro and other modern codecs, and with added SBR coding (HE AAC) it can provide quite high quality at low bitrates.

Recent developments have led to [[AACplus]] which is able to give subjectively good results at low bitrates. The website [[tuner2 | http://www.tuner2.com]] has several Internet radio stations which are sending out streams at low rates - such as 40 kbps - and some of these are surprisingly good considering the bit rates used.

===Pros===

* An international standard approved by the [http://www.iso.ch ISO]
* Flexible: supports several [[sampling rate]]s (8000-96000 Hz), bit depths, and [[multichannel]] (up to 48 channels)
* Several implementations, including free and high quality ones ([http://www.itunes.com iTunes] or [http://www.nero.com/nerodigital/eng/Nero_Digital_Audio.html Nero Digital])
* Reaches transparency in most samples and for most users at around 150kbps
* Part of [[MPEG-4]] specs
* Anyone can create its own implementation (specifications and demo sources available)
* Some portable players support it (Philips Expanium, [[Apple iPod]], cell phones from Nokia, Sony Jukebox)

===Cons===

* Problem cases that trip out all transform codecs
* Heavily patented
* Increased complexity
* '''AAC''' comes in different "flavors" (object types: '''AAC LC''', '''AAC HE''', '''AAC PS''' etc.). Many (especially portable) players only support LC (at the moment) so you can have files that are valid but your player won't play them.

==Technical Information==
'''AAC''' stands for 'Advanced Audio Coding' and is part of the [[MPEG-4]] Systems Standard. Originally known as MPEG-2 Non-Backwards Compatible (As apposed to MPEG-2 Backwards Compatible) it is the succesor to MPEG-1/2 Layer III ([[MP3]]). It uses the [[MP4]] [[container]] (which is based on Apple's [[MOV]] container) to store metadata (i.e. tag information).

As part of the MPEG-4 Systems Standard, an '''AAC''' encoded file can include up to 48 full-bandwith audio channels (up to 96 kHz) and 15 Low Frequency Enhancement channels (limited to 120 Hz) plus 15 data streams.

'''AAC''' encoding methods are organised into Profiles (MPEG-2) or Object Types (MPEG-4). These different Object Types are not necessarily compatible with each other and may not be playable with various decoders. Some of the various Object Types are:

* MPEG-2 AAC LC / Low Complexity
* MPEG-2 AAC Main
* MPEG-2 AAC SSR / Scalable Sampling Rate
* MPEG-4 AAC LC / Low Complexity
* MPEG-4 AAC Main
* MPEG-4 AAC SSR / Scalable Sampling Rate
* MPEG-4 AAC LTP / Long Term Prediction
* MPEG-4 AAC HE / High Efficiency
* MPEG-4 AAC LD / Low Delay

Different Object Types vary in complexity. Some take longer to encode/decode as a result of the different complexities. Furthermore, the benefits of the more complex profiles are often not worth the CPU power required to encode/decode them. As a result the Low Complexity/LC Object Type has become the profile used by most encoders and supported by most decoders. However, the High Efficiency (HE) Object Type has become more popular recently with its addition to the Nero '''AAC''' encoder.

Currently all players support the LC Object Type, although some will work on only MPEG2 or MPEG4 streams. Players based on the FAAD2 decoder (eg. [[foobar2000]], [[Winamp]] plugins) support almost all Object Types including HE '''AAC'''. 3ivX also supports all Object Types except SSR.

==Technologies used for compression==

* [[Huffman coding]]
* [[Quantization]] and scaling
* [[Joint stereo|M/S matrixing]]
* [[Intensity stereo]]
* Channel coupling
* Backward adaptive prediction
* Temporal Noise Shaping (TNS)
* Modified Discrete Cosine Transform (I[[MDCT]])
* Gain control and hybrid filter bank (polyphase quadrature filter (IPQF)+IMDCT)
* Long Term Predictor (LTP) - MPEG4 '''AAC''' only
* Perceptual Noise Substitution (PNS) - MPEG4 '''AAC''' only
* Spectral Band Replication ([[SBR]]) - HE '''AAC'''
* Parametric Stereo (PS) - HE '''AAC'''

==Encoders / Decoders (Supported Platforms)==

* [[Nero AAC]] (Win32)
* [[QuickTime AAC]] (Win32/MacOS X)
* [[FAAC]] [[FAAD]] (Multiplatform)
* HHI/zPlane [[Compaact!]] (Win32)
* [[PsyTEL]] (Win32)

==External References==

* [[AAC FAQ]]
* Known [[AAC implementations]].
* Read the [[AAC guide]] to learn how to obtain '''AAC'''/[[MP4]] files out of WAV files and CDs.
* Detailed '''AAC''' comparisons can be found at [http://www.rjamorim.com/test/ Roberto's listening tests page].

Advanced Audio Coding

2006-05-28T10:36:41Z

Guruboolez: /* Introduction */

==Introduction==
'''AAC''' or 'Advanced Audio Coding' forms part of the latest specifications from the MPEG committee, and is their official successor to the popular [[MP3]] format. As with MP3, the AAC format is an international standard, and is backed by several big-name companies, including Dolby, Sony and Nokia.

With the 13 years that had passed since the creation of the MP3 format, many improvements had been realised leading to a seemingly complex specification with several flavours of AAC available. To potentially add to the confusion, AAC is usually wrapped inside an [[MP4]] container to provide tagging, seeking and possibly other benefits?? For this reason, AAC can also be referred to as MP4 audio..

There are several AAC encoders to choose from, coming from large names such as Apple ([[iTunes]]) , Real Networks and Nero AG (Creators of Nero Burning Rom), or the open source [http://www.audiocoding.com FAAC] which is analogous to the [[LAME]] encoder. AAC is supported on some hardware players, most notably the [[Apple iPod]] and some cell phones, and is available in Apple's online store.

In terms of quality, the AAC format is on par with [[Ogg Vorbis]], [[LAME]] MP3, [[WMA]] Pro and other modern codecs, and with added SBR coding (HE AAC) it can provide quite high quality at low bitrates.

Recent developments have led to [[AACplus]] which is able to give subjectively good results at low bitrates. The website [[tuner2 | http://www.tuner2.com]] has several Internet radio stations which are sending out streams at low rates - such as 40 kbps - and some of these are surprisingly good considering the bit rates used.

===Pros===

* An international standard approved by the [http://www.iso.ch ISO]
* Flexible: supports several [[sampling rate]]s (8000-96000 Hz), bit depths, and [[multichannel]] (up to 48 channels)
* Several implementations, including a free and high quality one ([http://www.itunes.com iTunes])
* Reaches transparency in most samples and for most users at around 150kbps
* Part of [[MPEG-4]] specs
* Anyone can create its own implementation (specifications and demo sources available)
* Some portable players support it (Philips Expanium, [[Apple iPod]], cell phones from Nokia)

===Cons===

* Problem cases that trip out all transform codecs
* Heavily patented
* Increased complexity
* '''AAC''' comes in different "flavors" (object types: '''AAC LC''', '''AAC HE''', '''AAC PS''' etc.). Many (especially portable) players only support LC (at the moment) so you can have files that are valid but your player won't play them.

==Technical Information==
'''AAC''' stands for 'Advanced Audio Coding' and is part of the [[MPEG-4]] Systems Standard. Originally known as MPEG-2 Non-Backwards Compatible (As apposed to MPEG-2 Backwards Compatible) it is the succesor to MPEG-1/2 Layer III ([[MP3]]). It uses the [[MP4]] [[container]] (which is based on Apple's [[MOV]] container) to store metadata (i.e. tag information).

As part of the MPEG-4 Systems Standard, an '''AAC''' encoded file can include up to 48 full-bandwith audio channels (up to 96 kHz) and 15 Low Frequency Enhancement channels (limited to 120 Hz) plus 15 data streams.

'''AAC''' encoding methods are organised into Profiles (MPEG-2) or Object Types (MPEG-4). These different Object Types are not necessarily compatible with each other and may not be playable with various decoders. Some of the various Object Types are:

* MPEG-2 AAC LC / Low Complexity
* MPEG-2 AAC Main
* MPEG-2 AAC SSR / Scalable Sampling Rate
* MPEG-4 AAC LC / Low Complexity
* MPEG-4 AAC Main
* MPEG-4 AAC SSR / Scalable Sampling Rate
* MPEG-4 AAC LTP / Long Term Prediction
* MPEG-4 AAC HE / High Efficiency
* MPEG-4 AAC LD / Low Delay

Different Object Types vary in complexity. Some take longer to encode/decode as a result of the different complexities. Furthermore, the benefits of the more complex profiles are often not worth the CPU power required to encode/decode them. As a result the Low Complexity/LC Object Type has become the profile used by most encoders and supported by most decoders. However, the High Efficiency (HE) Object Type has become more popular recently with its addition to the Nero '''AAC''' encoder.

Currently all players support the LC Object Type, although some will work on only MPEG2 or MPEG4 streams. Players based on the FAAD2 decoder (eg. [[foobar2000]], [[Winamp]] plugins) support almost all Object Types including HE '''AAC'''. 3ivX also supports all Object Types except SSR.

==Technologies used for compression==

* [[Huffman coding]]
* [[Quantization]] and scaling
* [[Joint stereo|M/S matrixing]]
* [[Intensity stereo]]
* Channel coupling
* Backward adaptive prediction
* Temporal Noise Shaping (TNS)
* Modified Discrete Cosine Transform (I[[MDCT]])
* Gain control and hybrid filter bank (polyphase quadrature filter (IPQF)+IMDCT)
* Long Term Predictor (LTP) - MPEG4 '''AAC''' only
* Perceptual Noise Substitution (PNS) - MPEG4 '''AAC''' only
* Spectral Band Replication ([[SBR]]) - HE '''AAC'''
* Parametric Stereo (PS) - HE '''AAC'''

==Encoders / Decoders (Supported Platforms)==

* [[Nero AAC]] (Win32)
* [[QuickTime AAC]] (Win32/MacOS X)
* [[FAAC]] [[FAAD]] (Multiplatform)
* HHI/zPlane [[Compaact!]] (Win32)
* [[PsyTEL]] (Win32)

==External References==

* [[AAC FAQ]]
* Known [[AAC implementations]].
* Read the [[AAC guide]] to learn how to obtain '''AAC'''/[[MP4]] files out of WAV files and CDs.
* Detailed '''AAC''' comparisons can be found at [http://www.rjamorim.com/test/ Roberto's listening tests page].

Gapless playback

2006-01-29T15:23:34Z

Guruboolez: /* Test samples */

'''Gapless playback''' is the seamless playback of digital audio formats. It allows live music or consecutive tracks to be heard exactly as they are mastered, without gaps between tracks.

==Why gaps occur==
Most lossy audio compression schemes involve a time/frequency domain transform. Such transforms cannot deal with arbitrary amounts of data, and instead act on blocks of data at a time. In order for the audio signal to be encoded in its entirety, small amounts of silence are prepended and appended to the input before the transform. If the amount of padded silence is not accounted for, the playtime of the audio data may not be equal before and after the compression. In such cases, the silence will be decoded together with the audio data, introducing gaps between tracks.

Most audio playback software will also close the audio output stream when switching tracks, introducing gaps or making existing gaps larger. Unless the beginning of the next track is buffered and introduced immediately when the current track ends, gaps will occur.

Some compression methods such as the popular [[MP3]] can be problematic because the MP3 standard defines no way to record the amount of padding for later removal. Even if two tracks are decompressed and merged into a single track, a gap will remain between them. More recent audio formats have been designed to address this problem, and will produce gapless audio if played back correctly.

==Optimal solution==
It is possible to store metadata in the audio to explicitly declare the playtime, and/or the amount of padding/delays introduced in the encoding process. This information can be used to ensure that playtime will remain constant after decoding with no added silence. The audio playback software must be able to recognize the metadata, and trim the decoded audio as necessary.

The software can then take care to keep the output stream open between tracks. It must also buffer the beginning of the following track in the same way it buffers the current track during normal playback.

If the compression method supports gapless playback, the software properly decodes the audio data and metadata, the next track is buffered and ready to play, and the output stream remains open between tracks, optimal gapless audio is achieved. A collection of consecutive tracks will then play in the same way they were mastered, allowing the listener to hear their album as the author intended.

==Alternative solutions==
Digital signal processor ([[DSP]]) plugins can be used to detect silence between tracks and trim the audio as necessary on playback. This is not an optimal solution because it does not always produce results identical to the source. Sometimes an artist may intentionally leave silence at track boundaries for dramatic effect; removing this silence also removes that effect.

It can also be difficult to properly implement silence removal. If the silence threshold is too low and the track contains decoder artifacts, the software may not recognise some silences. Conversely, if the threshold is too high, the software may remove entire sections of quiet music at the beginning or end of a track.

DSP plugins can also be used to cross-fade between tracks. This eliminates gaps that some listeners find distracting, but also greatly alters the audio data and is not always desirable. In particular, when tracks are meant to be played together and perform the transition at high volume, cross-fading results in a large volume drop.

Both of these alternate solutions are typically used to address compression methods that do not support the metadata for gapless playback. Like the optimal solution, they still require buffering and not closing the output stream; however, they require more computations, making them less efficient. In portable digital audio players, this can mean a reduced playing time on batteries.

Due to the drawbacks of the alternative solutions above, some listeners dislike their negative effects more than the gap they attempt to remove.

Another alternative is to ignore track boundaries, encoding a single collection of tracks as a single compressed file, relying on [[cuesheet]]s (or something similar) for navigation. While this method results in gapless playback within the collection of tracks, it can be unwieldy due to the possibly large size of the resulting compressed file. Furthermore, unless the playback software or hardware can recognize the cue sheets, navigating between tracks may be difficult.

==Format support==
Since [[lossless]] data compression excludes the possibility of the introduction of padding, all lossless audio file formats are inherently gapless. The following [[lossy]] audio file formats have provisions for gapless encoding.

*[[Ogg Vorbis]]
*[[Speex]]

Some other formats do not officially support gapless encoding, but some implementations of encoders or decoders may handle gapless metadata.

*[[LAME]]-encoded MP3 can be gapless with players that support the LAME Mp3 info tag.
*[[AAC]] in [[MP4]] encoded with Nero Digital from [[Nero AG]] can be gapless with [[foobar2000]].

==Gapless solutions==
* [[foobar2000]]: Optimal gapless playback
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=18530 Otachan's in_mpg123]: A gapless [[MP3]] decoder for [[Winamp]]

==Test samples==
* [http://www.hydrogenaudio.org/forums/index.php?showtopic=40998]: Samples for testing gapless playback abilities
* [http://guruboolez.free.fr/samples/gapless/gapless_WAVPACK_free_of_right.zip]: 17 very short gapless samples (2 MB)

Lossless comparison

2005-12-31T18:13:35Z

Guruboolez: /* Links */

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> The Compression ratio is calculated with the division of compressed size by uncompressed size * 100. So, lower is better.

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://www.true-audio.com/

[[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===
* Limited player support

===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://guruboolez.free.fr/lossless/ Guruboolez'] - comparing only classical music;
* [http://uclc.info/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.

WavPack

2005-04-17T15:56:03Z

Guruboolez: /* CD writers/rippers */

'''WavPack''' is a free, open source lossless audio compression format developed by David Bryant.

==Description==

WavPack allows users to compress (and restore) both 16 and 24-bit audio files in the .[[WAV]] format. It also supports multichannel streams and high frequency sampling rates. Like other lossless compression schemes the data reduction varies with the source, but it is generally between 25% and 50% for typical popular music and somewhat better than that for classical music and other sources with greater dynamic range.

WavPack also incorporates a unique "hybrid" mode that provides all the advantages of lossless compression with an additional bonus. Instead of creating a single file, this mode creates both a relatively small, high-quality lossy file that can be used all by itself, and a "correction" file that (when combined with the lossy file) provides full lossless restoration. For some users this means never having to choose between lossless and lossy compression!

==Feature Summary==

* Fast and efficient encoding and decoding
* [[Open source]], released under a BSDish license
* Multiplatform
* Error robustness
* Streaming support
* Supports multichannel audio and high resolutions
* Hybrid/lossy mode
* Tagging support ([[ID3v1]], [[APE]])
* Supports [[RIFF]] chunks
* Supports embedded CUE sheets
* Includes MD5 hashes for quick integrity checking
* Self-extracting mode
* [[ReplayGain]] compatible

==History==

David Bryant started development on WavPack in mid-1998, with the release of version 1.0. This first version compressed and decompressed audio losslessly, nothing else, but by then it already featured one of the best efficiency vs. speed ratio among lossless encoders.

Very soon after the release of version 1.0, Bryant released v. 2.0, which featured lossy encoding (using only quantization for data reduction - no psychoacoustic process was applied to the stream).

In 1999, the developer released version 3.0, which featured novelties such as a fast mode (with reduced compression ratio), compression of RAW files and error detection using CRC checksums.

WavPack development is still going on, and a major feature added in late 3.x versions is the hybrid mode, where the encoder generates a lossy file + a correction file, so that both can be decompressed back to the original PCM stream.

WavPack 4 has been recently released. It included important changes, such as fast seeking, multichannel support, high resolution audio support, etc. turning it into one of the most full featured and modern lossless audio compressors.

==Software support==

===Players===

* NullSoft [[Winamp]] (plugin w/ ReplayGain & Media Library support) and Winamp-compatible players
* [[foobar2000]] Advanced Audio Player (official encoding/decoding addon, w/ ReplayGain & Cuesheets support)
* [http://www.vuplayer.com/vuplayer.htm VUPlayer] (official plugin, supports encoding)
* [[Windows Media Player]] and other directshow-based players (MPC, TCMP, RadLight) (with [http://corewavpack.corecodec.org/ CoreWavPack] directshow filter)
* [http://koti.welho.com/hylinen/apollo/ Apollo] Audio Player (plugin w/ ReplayGain support)
* [http://www.un4seen.com/xmplay.html XMplay] (official plugin)

* [[XMMS]] (with Kuniklo's plugin)
* [http://fondriest.frederic.free.fr/realisations/lamip/ LAMIP] (official plugin)

===Frontends===

* Custom [http://members.home.nl/w.speek/wavpack.htm Windows Frontend] (by Speek)
* [http://www.unifront.boereck.de/ UniversalFront] by Böreck
* [http://home.vxu.se/mdati00/frontah/ Frontah] by Madah
* [http://mareo.monkeydev.org/ Mareo] by Kwambis

===Converters===
(Several players, like foobar2000 and VUplayer, can also convert from other formats to WavPack)

* [http://www.dbpoweramp.com/ dBpowerAMP] Music Converter / Audio Player / CD Writer (official addon)
* [http://www.board-24.de/ GX:Transcoder] Music converter

===Editors===

* [[Adobe Audition]] and CoolEdit (filter w/ 32-bit floats & extra info save support)

===CD writers/rippers===

* [http://www.ahead.de Ahead Nero Burning Rom]
* [http://www.burrrn.net Burrrn] Audio CD burner
* [[Exact Audio Copy]] CD Ripper
* [http://cdexos.sourceforge.net CDex] CD ripper

===Taggers===

* [http://www.mp3tag.de/en/index.html Mp3tag] Universal Tag Editor
* [http://users.otenet.gr/~jtcliper/tgf/ The GodFather] Tagger / Music manager
* [http://www.saunalahti.fi/cse/files/Tag.zip Case's Tag] command line tagger

===Other tools===

* [http://www.burrrn.net/mrq/ Mr. QuestionMan] / [http://www.bitattack.ro/ai/ Audio Identifier]
* [http://www.bunkus.org/videotools/mkvtoolnix/ mkvtoolnix] - tool to multiplex WavPack streams inside the Matroska container
It's worth mentioning the [http://www.matroska.org Matroska] guys decided to concentrate on WavPack as the
lossless compressor of choice for their container. Quite an honor... :-)

==Technology description==

To ensure high-speed operation, WavPack uses a very simple predictor that is implemented entirely in integer math. In its "fast" mode the prediction is simply the arithmetic extrapolation of the previous two samples. For example, if the previous two samples were -10 and 20, then the prediction would be 50. For the default mode a simple adaptive factor is added to weigh the influence of the earlier sample on the prediction. In our example the resulting prediction could then vary between 20 for no influence to 50 for full influence. This weight factor is constantly updated based on the audio data's changing spectral characteristics, which is why it is called "adaptive".

The prediction generated is then subtracted from the actual sample to be encoded to generate the error value. In mono mode this value is sent directly to the coder. However, stereo signals tend to have some correlation between the two channels that can be further exploited. Therefore, two error values are calculated that represent the difference and average of the left and right error values. In the "fast" mode of operation these two new values are simply sent to the coder instead of the left and right values. In the default mode, the difference value is always sent to the coder along with one of the other three values (average, left, or right). An adaptive algorithm continuously determines the most efficient of the three to send based on the changing balance of the channels.

The developer has developed a unique data encoder for WavPack that he believes is better than Rice coding in two different areas. It is impossible to encode more efficiently than Rice coding because it represents the optimal bit coding (sometimes known as the Huffman code) for this type of data. WavPack's encoder is slightly less efficient than this, but only by about 0.15 bits/sample (or less than 1% for 16-bit data). The first advantage of WavPack's coder is that it does not require the data to be buffered ahead of encoding, instead it converts each sample directly to bitcodes. This is more computationally efficient and it is better in some applications where coding delay is critical. The second advantage is that it is easily adaptable to lossy encoding because all significant bits (except the implied "one" MSB) are transmitted directly. In this way it is possible to only transmit, for example, the 3 most significant bits (with sign) of each sample. In fact, it is possible to transmit only the sign and implied MSB for each sample with an average of only 3.65 bits/sample.

This coding scheme is used to implement the "lossy" mode of WavPack. In the "fast" mode the output of the non-adaptive decorrelator is simply rounded to the nearest codable value for the specified number of bits. In the default mode the adaptive decorrelator is used (which reduces the average noise about 1 dB) and also both the current and the next sample are considered in choosing the better of the two available codes (which reduces noise another 1 dB).

The decoder has decided to not use any floating-point arithmetic in WavPack's data path because he believes that integer operations are less susceptible to subtle chip to chip variations that could corrupt the lossless nature of the compression, the Pentium floating point bug being a blatant example of this. It is possible that a lossless compressor that used floating-point math could generate different output when running on that faulty Pentium. Even disregarding actual bugs, floating-point math is complicated enough that there could be subtle differences between "correct" implementations that could cause trouble for this type of application. To further ensure confidence in the integrity of WavPack's compression, the encoder includes a 32-bit error detection code to the generated streams.

==Further reading==

* [http://www.wavpack.com/ Official website]
* [http://www.rjamorim.com/rrw/wavpack.html Historical versions at ReallyRareWares]
* [[Lossless_comparison|Lossless Codec Comparison]] by Rjamorim
* [[EAC_and_WavPack | Configuring EAC and Wavpack]]