Editing Digital Picture Exchange

{{Short description|Image file format family}}
{{redirect|DPX|text=DPX is also the name given to a mounting medium, see [[Dibutyl phthalate|Di-n-butyl phthalate]] in [[Xylene]]}}
{{ Infobox file format
| name          = Digital Picture Exchange
| extension     = <code>.dpx</code>
| mime          = 
| developer     = [[SMPTE]]
| released      = 1.0 / {{Start date and age|1994|02|18|df=yes}}
| latest release version = 2.0HDR
| latest release date    = {{Start date and age|2018}}
| creatorcode   = 
| genre         = [[Image file formats]]
| standard      = ST 268-1:2014,<ref>{{cite book|doi=10.5594/SMPTE.ST268-1.2014|isbn=978-1-68303-083-6|publisher=[[SMPTE]]|title=ST 268-1:2014 - SMPTE Standard - File Format for Digital Moving-Picture Exchange (DPX)}}</ref> ST 268-2:2018<ref>{{cite book|doi=10.5594/SMPTE.ST268-2.2018|isbn=978-1-68303-161-1|publisher=[[SMPTE]]|title=ST 268-2:2018 - SMPTE Standard - Digital Moving-Picture Exchange (DPX) – Format Extensions for High Dynamic Range and Wide Color Gamut|s2cid=252588275 }}</ref>
| open          = non-free [[SMPTE]] standard, USD 175 
| container for = 
| extended from = [[Cineon]]
| url           = {{URL|http://www.smpte.org/}}
}}

'''Digital Picture Exchange''' ('''DPX''') is a common [[file format]] for [[digital intermediate]] and [[visual effects]] work and is a [[SMPTE]] standard (ST 268-1:2014). The file format is most commonly used to represent the [[Optical density|density]] of each colour channel of a scanned negative film in an uncompressed "[[logarithmic scale|logarithmic]]" image where the [[Gamma correction|gamma]] of the [[original camera negative]] is preserved as taken by a [[film scanner]]. For this reason, DPX is the worldwide-chosen format for still frames storage in most digital intermediate post-production facilities and film labs. Other common video formats are supported as well (see below), from video to purely digital ones, making DPX a file format suitable for almost any raster digital imaging applications. DPX provides, in fact, a great deal of flexibility in storing colour information, colour spaces and colour planes for exchange between production facilities. Multiple forms of packing and alignment are possible. The DPX specification allows for a wide variety of metadata to further clarify information stored (and storable) within each file.

The DPX file format was originally derived from the [[Kodak]] [[Cineon]] open file format (<code>.cin</code> file extension) used for digital images generated by Kodak's original [[film scanner]]. The original DPX (version 1.0) specifications are part of SMPTE 268M-1994.<ref>{{cite web|url=http://www.cineon.com/ff_draft.php|title=Cineon Image File Format Draft|publisher=[[Cineon]]|access-date=2014-03-01|archive-url=https://web.archive.org/web/20130529225913/http://www.cineon.com/ff_draft.php|archive-date=2013-05-29|url-status=dead}}</ref> The specification was later improved and published by [[SMPTE]] as [[American National Standards Institute|ANSI]]/SMPTE 268M-2003. Academy Density Exchange (ADX) support for the [[Academy Color Encoding System]] are added in the current version of the standard SMPTE ST 268-1:2014. Extensions for [[high-dynamic-range video]] and [[wide color gamut]] are standardized in SMPTE ST 268-2:2018.

== Metadata and standard flexibility ==
[[SMPTE]] specifications dictate a mild number of compulsory metadata, like image resolution, [[color space]] details (channel depth, colorimetric metric, etc.), number of planes/subimages, as well as original filename and creation date/time, creator's name, project name, [[copyright]] information, and so on.

Furthermore, a couple of industry-specific metadata areas are present: Motion-Picture and Television ones. They are either used only if the picture has enough embedded information relevant to that specific industry, otherwise are left "empty". For example, Motion-Picture-specific metadata includes perforation-exact [[35mm format|film]] [[KeyKode]] (if the image comes from a film scan), camera shutter angle, slate information and frame positioning within a frame sequence. On the other side, Television metadata includes full [[SMPTE time code]], video overscan and field information, and signal/colour level information.

A third, variable-size metadata area, which is user-definable, exists. Third-party applications/software occasionally use this area to store additional information; for example, when the DPX stores images with technical specifications far away from the original standard (like pictures coded in the [[International Commission on Illumination|CIE]] ''[[CIE 1931 color space|XYZ]]'' color space, or [[Bayer filter|Bayer]]-patterned raw frames from specific digital cameras like the [[Arriflex D-21]]).

SMPTE ST 268-2:2018 defines a standards-based metadata section that supports [[Extensible Metadata Platform]], [[XML]], and [[KLV]] metadata representations.

== Support ==
[[XnView]] can read [[FFmpeg]] <code>pix_fmt=abgr</code> DPX images. [[ImageMagick]] supports DPX.<ref>{{cite web|title=ImageMagick Motion Picture Formats|url=https://www.imagemagick.org/script/motion-picture.php|url-status=live|access-date=2014-03-01|publisher=[[ImageMagick]]|archive-url=https://web.archive.org/web/20070626184202/http://www.imagemagick.org:80/script/motion-picture.php |archive-date=2007-06-26 }}</ref> The C++ source of a DPX library is available.<ref>{{Citation|last=Palmer|first=Patrick|title=PatrickPalmer/dpx|date=2021-04-22|url=https://github.com/PatrickPalmer/dpx|access-date=2021-05-19}}</ref> DjV,<ref>{{Cite web|title=DJV|url=https://darbyjohnston.github.io/DJV/|access-date=2021-05-19|website=darbyjohnston.github.io}}</ref> and vooya<ref>{{Cite web|title=vooya YUV/RGB player|url=http://www.offminor.de/vooya_yuv_player.html|access-date=2021-05-19|website=Off Minor|language=en}}</ref> support DPX sequences. [[IrfanView]] also has support for DPX images through a plugin. <ref>{{cite web |last1=Skiljan |first1=Irfan |title=IrfanView PlugIns |url=https://www.irfanview.com/plugins.htm |website=www.irfanview.com |access-date=27 February 2023}}</ref>
[https://lasergraphics.com Lasergraphics motion picture film scanning systems] include support for output to DPX color/B&W 10/16-bit (conforms to SMPTE 268M for compatibility with graphics, compositing, and other post production systems).

== See also ==
*[[Comparison of graphics file formats]]
* [[Digital film]]
* [[Digital intermediate]]
* [[Display resolution]]
* [[Film-out]]
* [[Film recorder]]
* [[Material Exchange Format]] (MXF), media container format
* [[Post-production]]
* [[Telecine]]

== References ==
{{reflist}}

{{Graphics file formats}}
{{SMPTE standards}}

[[Category:Graphics file formats]]
[[Category:SMPTE standards]]