词条 | FLAC | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
释义 |
| name = Free Lossless Audio Codec | logo = Flac logo vector.svg | screenshot = | caption = | developer = Xiph.Org Foundation, Josh Coalson, Erik de Castro Lopo | released = {{Start date and age|2001|07|20|df=yes}} | latest_release_version = [https://xiph.org/flac/changelog.html 1.3.2] | latest_release_date = {{Start date and age|2017|01|01|df=yes}} | operating_system = Cross-platform | genre = Codec | license = Command-line tools: GNU GPL Libraries: BSD | website = {{url|https://xiph.org/flac}} }}{{Infobox file format | name = Free Lossless Audio Codec | icon = | logo = | extension = .flac | mime = audio/flac | type code = | uniform type = | magic = fLaC[1] | owner = | genre = Audio | container for = | contained by = | extended from = | extended to = | standard = {{URL|https://xiph.org/flac/format.html}} | free = Yes[2] }} FLAC ({{IPAc-en|f|l|æ|k}}; Free Lossless Audio Codec) is an audio coding format for lossless compression of digital audio, and is also the name of the free software project producing the FLAC tools, the reference software package that includes a codec implementation. Digital audio compressed by FLAC's algorithm can typically be reduced to between 50 and 70 percent of its original size[3] and decompress to an identical copy of the original audio data. FLAC is an open format with royalty-free licensing and a reference implementation which is free software. FLAC has support for metadata tagging, album cover art, and fast seeking. HistoryDevelopment was started in 2000 by Josh Coalson.[4] The bit-stream format was frozen when FLAC entered beta stage with the release of version 0.5 of the reference implementation on 15 January 2001. Version 1.0 was released on 20 July 2001.[4] On 29 January 2003, the Xiph.Org Foundation and the FLAC project announced the incorporation of FLAC under the Xiph.org banner. Xiph.org is behind other free compression formats such as Vorbis, Theora, Speex and Opus.[4][5][6] Version 1.3.0 was released on 26 May 2013, at which point development was moved to the Xiph.org git repository.[7] CompositionThe FLAC project consists of:
The specification of the stream format can be implemented by anyone without prior permission (Xiph.org reserves the right to set the FLAC specification and certify compliance), and neither the FLAC format nor any of the implemented encoding or decoding methods are covered by any patent. The reference implementation is free software. The source code for libFLAC and libFLAC++ is available under the BSD license, and the sources for In its stated goals, the FLAC project encourages its developers not to implement copy prevention features (DRM) of any kind.[8] DesignAudio sources encoded to FLAC are typically reduced to 50–70% of their original size, similar to other lossless formats, though the final size depends on the density and volume of the music being compressed, and, with some music, file size can be reduced by as much as 80%.[3] Source encoder
Metadata
Compression levelslibFLAC uses a compression level parameter that varies from 0 (fastest) to 8 (slowest). The compressed files are always perfect, lossless representations of the original data. Although the compression process involves a tradeoff between speed and size, the decoding process is always quite fast and not dependent on the level of compression.[11][12] According to a .WAV benchmark,[13] using higher rates above default level -5, takes considerably more time to encode without real gains in space savings.
Comparison to other formatsFLAC is specifically designed for efficient packing of audio data, unlike general-purpose lossless algorithms such as DEFLATE, which is used in ZIP and gzip. While ZIP may reduce the size of a CD-quality audio file by 10–20%, FLAC is able to reduce the size of audio data by 40–50% by taking advantage of the characteristics of audio. The technical strengths of FLAC compared to other lossless formats lie in its ability to be streamed and decoded quickly, independent of compression level. Since FLAC is a lossless scheme, it is suitable as an archive format for owners of CDs and other media who wish to preserve their audio collections. If the original media are lost, damaged, or worn out, a FLAC copy of the audio tracks ensures that an exact duplicate of the original data can be recovered at any time. An exact restoration from a lossy copy (e.g., MP3) of the same data is impossible. FLAC being lossless means it is highly suitable for transcoding e.g. to MP3, without the normally associated transcoding quality loss between one lossy format and another. A CUE file can optionally be created when ripping a CD. If a CD is read and ripped perfectly to FLAC files, the CUE file allows later burning of an audio CD that is identical in audio data to the original CD, including track order and pregap, but excluding CD-Text and other additional data such as lyrics and CD+G graphics.[10] Adoption and implementations{{see also|List of hardware and software that supports FLAC}}The reference implementation of FLAC is implemented as the libFLAC core encoder & decoder library, with the main distributable program FLAC playback support in portable audio devices and dedicated audio systems is limited compared to formats such as MP3[14] or uncompressed PCM. FLAC support is included by default in Windows 10, Android, Blackberry 10 and Jolla devices. In 2014, several aftermarket mobile electronics companies introduced multimedia solutions that include support for FLAC. These include the NEX series from Pioneer Electronics and the VX404 and NX404 from Clarion. The European Broadcasting Union (EBU) has adopted the FLAC format for the distribution of high quality audio over its Euroradio network.[15] The Windows operating system has supported native FLAC integration since the introduction of Windows 10.[16] The Android operating system has supported native FLAC playback since version 3.1.[17][18] macOS High Sierra and iOS 11 add native FLAC playback support.[19] Among others the Pono music player and streaming service used the FLAC format.[20][21] Bandcamp insists on a lossless format for uploading, and has FLAC as a download option.[22] The Wikimedia Foundation sponsored a free and open-source online ECMAScript FLAC tool for browsers supporting the required HTML5 features.[23]
See also{{Portal|Free and open-source software}}
References1. ^{{cite web |url=https://xiph.org/flac/format.html#stream |accessdate={{date|2013-04-04}}|title=FLAC - format |first=Josh |last=Coalson |quote="fLaC", the FLAC stream marker in ASCII, meaning byte 0 of the stream is 0x66, followed by 0x4C 0x61 0x43}} 2. ^{{cite web |url=http://www.fsf.org/campaigns/playogg/en/ |title=PlayOgg! |website=Free Software Foundation |accessdate={{date|2013-10-01}} |date={{date|2010-03-17}}}} 3. ^1 {{cite web |url=https://hbfs.wordpress.com/2012/02/07/looking-at-flac-compression-ratios/ |title=Looking At Flac Compression Ratios |accessdate=10 May 2018 |publisher=Steven Pigeon}} 4. ^1 2 {{cite web |url=https://xiph.org/flac/news.html |title=News |accessdate=31 August 2009|publisher=FLAC}} 5. ^{{cite web |website=Xiph.org Foundation |url=https://www.xiph.org/press/2003/flac/ |title=FLAC Joins Xiph.org |date=29 January 2003 |accessdate=31 August 2009}} 6. ^{{cite web |first=Emmett |last=Plant |website=Xiph.org Foundation |url=http://xiph.org/ogg/flac.html |title=FLAC Joins Xiph! |accessdate=31 August 2009 |archiveurl=https://web.archive.org/web/20080529055542/http://xiph.org/ogg/flac.html |archivedate=29 May 2008 |deadurl=yes |df=dmy-all }} 7. ^{{cite web |website=Xiph.org Foundation |url=https://xiph.org/flac/changelog.html |title=FLAC – changelog |accessdate=15 October 2013}} 8. ^{{cite web |url=https://xiph.org/flac/developers.html |title=Developers |website=FLAC |accessdate=15 October 2013}} 9. ^{{cite web |url=https://xiph.org/flac/format.html#frame_header |title=Format |website=FLAC |accessdate=20 May 2017}} 10. ^1 {{cite web |url=https://xiph.org/flac/faq.html |title=FAQ |website=FLAC |accessdate=23 September 2014}} 11. ^{{Cite web |url=http://www.cuetools.net/wiki/CUETools_FLAC_encoders_comparison |title=CUETools FLAC encoders comparison |website=CUETools Wiki |accessdate=27 May 2013}} 12. ^{{cite web |url=http://wiki.jriver.com/index.php/Encoding_Settings |title=Encoding Settings |website=JRiver Media Centre |accessdate=27 May 2013}} 13. ^{{cite web |title=Lossless Codec Comparison |url=http://synthetic-soul.co.uk/comparison/lossless/index.asp |website=Synthetic-soul.co.uk |accessdate=26 November 2016 |archiveurl=https://web.archive.org/web/20090202063734/http://synthetic-soul.co.uk:80/comparison/lossless/index.asp |archivedate=2 February 2009 |deadurl=yes |df=dmy-all}} 14. ^{{cite web |url=https://xiph.org/flac/links.html#hardware |title=Links |website=FLAC |accessdate=24 March 2009}} 15. ^{{cite web |url=https://www.ebu.ch/en/radio/ops_rdo/faq/index.php |title=What is the EBU Musipop system? |website=EBU}} 16. ^{{Cite web |title=Audio snobs rejoice: Windows 10 will have system-wide FLAC support |url=http://www.pcworld.com/article/2852595/audio-snobs-rejoice-windows-10-will-have-system-wide-flac-support.html |website=PC World |accessdate={{date|2015-07-10}}}} 17. ^{{cite web |url=https://developer.android.com/guide/appendix/media-formats.html |title=Android Supported Media Formats |date=4 August 2011 |website=Android.com |accessdate=27 February 2012}} 18. ^{{cite web |url=https://code.google.com/p/android/issues/detail?id=1461 |title=Issue 1461 – android – FLAC file support enhancement request |website=Google Code |accessdate=5 August 2011}} 19. ^{{cite web |url=http://www.idownloadblog.com/2017/06/09/ios-11-brings-lossless-flac-audio-to-iphone-and-ipad/ |title=iOS 11 brings lossless FLAC audio playback to iPhone and iPad |date=9 June 2017 |website=idownloadblog.com |accessdate=26 September 2017}} 20. ^{{cite web |url=http://www.ponomusic.com/#faq |title=FAQ |date=14 March 2014 |website=ponomusic.com |accessdate=14 March 2014}} 21. ^{{cite web |url=http://www.qobuz.com |title=Home |website=Qobuz.com |accessdate=10 April 2014}} 22. ^{{cite web |title=Why won’t my tracks upload? |url=https://bandcamp.com/help/uploading |website=Bandcamp |accessdate=21 June 2015}} 23. ^{{cite web |url=https://blog.rillke.com/flac.js/ |title=JavaScript FLAC de- and encoder |author=Rillke |date=2015 |accessdate={{date|2015-02-09}}}} External links{{Commons category|Free Lossless Audio Codec}}
6 : 2001 software|Cross-platform software|Free audio codecs|Lossless audio codecs|Xiph.Org projects|Open formats |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识,基本涵盖了大多数领域的百科知识,是一部内容自由、开放的电子版国际百科全书。