Editing JPEG (section)

===JPEG standard===
"JPEG" stands for [[Joint Photographic Experts Group]], the name of the committee that created the JPEG standard and other still picture coding standards. The "Joint" stood for [[ISO]] TC97 WG8 and [[CCITT]] SGVIII. Founded in 1986, the group developed the JPEG standard during the late 1980s. The group published the JPEG standard in 1992.<ref name="Hudson">{{cite journal |last1=Hudson |first1=Graham |last2=Léger |first2=Alain |last3=Niss |first3=Birger |last4=Sebestyén |first4=István |last5=Vaaben |first5=Jørgen |title=JPEG-1 standard 25 years: past, present, and future reasons for a success |journal=[[Journal of Electronic Imaging]] |date=31 August 2018 |volume=27 |issue=4 |page=1 |doi=10.1117/1.JEI.27.4.040901|s2cid=52164892 |doi-access=free }}</ref>

In 1987, ISO TC 97 became ISO/IEC JTC 1 and, in 1992, CCITT became ITU-T. Currently on the JTC1 side, JPEG is one of two sub-groups of [[International Organization for Standardization|ISO]]/[[International Electrotechnical Commission|IEC]] [[ISO/IEC JTC 1|Joint Technical Committee 1]], Subcommittee 29, Working Group 1 ([[ISO/IEC JTC 1/SC 29]]/WG 1)&nbsp;– titled as ''Coding of still pictures''.<ref name="sc29-wg1">{{cite web |url=http://kikaku.itscj.ipsj.or.jp/sc29/29w12901.htm |title=ISO/IEC JTC 1/SC 29/WG 1&nbsp;– Coding of Still Pictures (SC 29/WG 1 Structure) |author=ISO/IEC JTC 1/SC 29 |date=2009-05-07 |access-date=2009-11-11  |archive-url=https://web.archive.org/web/20131231055215/http://kikaku.itscj.ipsj.or.jp/sc29/29w12901.htm |archive-date=2013-12-31 }}</ref><ref name="jpeg-sc29">{{cite web |url=http://kikaku.itscj.ipsj.or.jp/sc29/29w42901.htm |title=Programme of Work, (Allocated to SC 29/WG 1) |author=ISO/IEC JTC 1/SC 29 |access-date=2009-11-07  |archive-url=https://web.archive.org/web/20131231012300/http://kikaku.itscj.ipsj.or.jp/sc29/29w42901.htm |archive-date=2013-12-31 }}</ref><ref>{{cite web |url=http://www.iso.org/iso/standards_development/technical_committees/list_of_iso_technical_committees/iso_technical_committee.htm?commid=45316 |title=JTC 1/SC 29&nbsp;– Coding of audio, picture, multimedia and hypermedia information |author=ISO |access-date=2009-11-11 |archive-date=2010-07-03 |archive-url=https://web.archive.org/web/20100703085542/http://www.iso.org/iso/standards_development/technical_committees/list_of_iso_technical_committees/iso_technical_committee.htm?commid=45316 |url-status=live }}</ref> On the ITU-T side, ITU-T SG16 is the respective body. The original JPEG Group was organized in 1986,<ref name="jpeg-jpeg">{{cite web | url=http://www.jpeg.org/jpeg/index.html | title=Joint Photographic Experts Group, JPEG Homepage | author=JPEG | access-date=2009-11-08 | archive-date=2009-09-27 | archive-url=https://web.archive.org/web/20090927035043/http://www.jpeg.org/jpeg/index.html | url-status=live }}</ref> issuing the first JPEG standard in 1992, which was approved in September 1992 as '''[[ITU-T]] Recommendation T.81'''<ref>{{cite web|url=http://www.itu.int/rec/T-REC-T.81|title=T.81: Information technology&nbsp;– Digital compression and coding of continuous-tone still images&nbsp;– Requirements and guidelines|website=Itu.int|access-date=2009-11-07|archive-date=2012-11-06|archive-url=https://web.archive.org/web/20121106222712/http://www.itu.int/rec/T-REC-T.81|url-status=live}}</ref> and, in 1994, as '''[[International Organization for Standardization|ISO]]/[[International Electrotechnical Commission|IEC]] 10918-1'''.

The JPEG standard specifies the [[codec]], which defines how an image is compressed into a stream of [[byte]]s and decompressed back into an image, but not the file format used to contain that stream.<ref>
{{cite book
 | title = JPEG still image data compression standard
 | edition = 3rd
 |author1=William B. Pennebaker |author2=Joan L. Mitchell|author2-link=Joan L. Mitchell | publisher = Springer
 | year = 1993
 | isbn = 978-0-442-01272-4
 | page = 291
 | url = https://books.google.com/books?id=AepB_PZ_WMkC&dq=JPEG+%22did+not+specify+a+file+format%22&pg=PA291
 }}</ref>
The [[Exif]] and [[JFIF]] standards define the commonly used file formats for interchange of JPEG-compressed images.

JPEG standards are formally named as ''Information technology&nbsp;– Digital compression and coding of continuous-tone still images''. ISO/IEC 10918 consists of the following parts:

{| class="wikitable sortable" style="width:100%;"
|+Digital compression and coding of continuous-tone still images&nbsp;–&nbsp;Parts<ref name="jpeg-sc29" /><ref name="jpeg-jpeg" /><ref>{{cite web |url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_tc_browse.htm?commid=45316 |title=JTC 1/SC 29&nbsp;– Coding of audio, picture, multimedia and hypermedia information |author=ISO |access-date=2009-11-07 |archive-date=2010-07-03 |archive-url=https://web.archive.org/web/20100703224947/http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_tc_browse.htm?commid=45316 |url-status=live }}</ref>
|-
! style="width:6%;"| Part
! style="width:15%;"| ISO/IEC standard
! style="width:10%;"| ITU-T Rec.
! style="width:8%;"| First public release date
! style="width:8%;"| Latest amendment
! style="width:30%;"| Title
! Description
|-
| Part 1
| [https://www.iso.org/standard/18902.html ISO/IEC 10918-1:1994]
| [http://www.itu.int/rec/T-REC-T.81 T.81 (09/92)]
| {{dts|abbr=on|1992-09-18}}
|
| Requirements and guidelines
|
|-
| Part 2
| [https://www.iso.org/standard/20689.html ISO/IEC 10918-2:1995]
| [http://www.itu.int/rec/T-REC-T.83 T.83 (11/94)]
| {{dts|abbr=on|1994-11-11}}
|
| Compliance testing
| Rules and checks for software conformance (to Part 1).
|-
| Part 3
| [https://www.iso.org/standard/25037.html ISO/IEC 10918-3:1997]
| [http://www.itu.int/rec/T-REC-T.84 T.84 (07/96)]
| {{dts|abbr=on|1996-07-03}}
| {{dts|abbr=on|1999-04-01}}
| Extensions
| Set of extensions to improve the Part 1, including the '''Still Picture Interchange File Format''' (SPIFF).<ref name="spiffloc" >{{cite web|url=https://www.loc.gov/preservation/digital/formats/fdd/fdd000019.shtml|title=SPIFF, Still Picture Interchange File Format |date=30 January 2012 |publisher= [[Library of Congress]] |access-date=2018-07-31 |archive-url=https://web.archive.org/web/20180731093543/https://www.loc.gov/preservation/digital/formats/fdd/fdd000019.shtml |archive-date=2018-07-31 |url-status=live}}</ref>
|-
| Part 4
| [https://www.iso.org/standard/85634.html ISO/IEC 10918-4:2024]
| [http://www.itu.int/rec/T-REC-T.86 T.86 (06/98)]
| {{dts|abbr=on|1998-06-18}}
|
| Appn Markers
| methods for registering some of the parameters used to extend JPEG
|-
| Part 5
| [https://www.iso.org/standard/54989.html ISO/IEC 10918-5:2013]
| [http://www.itu.int/rec/T-REC-T.871 T.871 (05/11)]
| {{dts|abbr=on|2011-05-14}}
|
| JPEG File Interchange Format (JFIF)
| A popular format which has been the de facto file format for images encoded by the JPEG standard. In 2009, the JPEG Committee formally established an Ad Hoc Group to standardize JFIF as JPEG Part 5.<ref name="jfif-development">{{cite press release|url=http://www.jpeg.org/newsrel25.html |title=JPEG XR enters FDIS status JPEG File Interchange Format (JFIF) to be standardized as JPEG Part 5 |author=Louis Sharpe|date=2009-04-24 |access-date=2009-11-09  |archive-url=https://web.archive.org/web/20091008041637/http://www.jpeg.org/newsrel25.html |archive-date=2009-10-08 }}</ref>
|-
| Part 6
| [https://www.iso.org/standard/59634.html ISO/IEC 10918-6:2013]
| [http://www.itu.int/rec/T-REC-T.872 T.872 (06/12)]
| {{dts|abbr=on|2012-06}}
|
| Application to printing systems
| Specifies a subset of features and application tools for the interchange of images encoded according to the ISO/IEC 10918-1 for printing.
|-
|Part 7
|[https://www.iso.org/standard/85635.html ISO/IEC 10918-7:2023]
|[http://www.itu.int/rec/T-REC-T.873 T.873 (06/21)]
|May 2019
|November 2023
|Reference Software
|Provides reference implementations of the JPEG core coding system
|}

[[Ecma International]] <abbr title="Technical Report">TR</abbr>/98 specifies the JPEG File Interchange Format (JFIF); the first edition was published in June 2009.<ref>{{cite web
|url=http://www.ecma-international.org/publications/techreports/E-TR-098.htm
|year=2009
|title=JPEG File Interchange Format (JFIF)
|access-date=2011-08-01
|work=ECMA TR/98 1st ed.
|publisher=[[Ecma International]]
|archive-date=2021-01-14
|archive-url=https://web.archive.org/web/20210114101520/http://www.ecma-international.org/publications/techreports/E-TR-098.htm
|url-status=live
}}</ref>