CinemaDNG

CinemaDNG is the result of an Adobe-led initiative to define an industry-wide open file format for digital cinema files.^[1] CinemaDNG caters for sets of movie clips, each of which is a sequence of raw video images, accompanied by audio and metadata. CinemaDNG supports stereoscopic cameras and multiple audio channels. CinemaDNG specifies directory structures containing one or more video clips, and specifies requirements and constraints for the open format files, (DNG, TIFF, XMP, and/or MXF), within those directories, that contain the content of those clips.^[2]

CinemaDNG is different from the Adobe DNG (Digital Negative) format that is primarily used as a raw image format for still cameras. However, each CinemaDNG image is encoded using that DNG image format. The image stream can then be stored in one of two formats: either as video essence using frame-based wrapping in an MXF file, or as a sequence of DNG image files in a specified file directory. Each clip uses just one of these formats, but the set of clips in a movie may use both.

Rationale

The purpose of CinemaDNG is to streamline workflows and help ensure easy archiving and exchange. There are several advantages from using raw image data for cinema, just as there are for still photography, but like the latter the presence of proprietary raw formats can inhibit the required integration. Movie development typically involves complicated workflows involving many stages and multiple suppliers of software and hardware components.^[3] All of these indicate the desirability of using open formats.

The ability to store images either within an MXF wrapper or as a DNG-sequence, with the ability to transfer from one to the other, provides extra flexibility. An additional benefit of using DNG is that there can be interchange between a CinemaDNG workflow and a still camera workflow.^[2] One use is to extract stills from a movie for publicity or other purposes.

The DNG images that Adobe provided in the short example of how to store a video clip as a sequence of DNG files,^[4] (see "Tangible deliverables"), were taken with a Canon EOS 30D dSLR camera, (and converted to DNG), rather than with a more conventional movie camera. This shows how any boundaries between different types of photography are weak, and illustrates why such open formats are important for the workflows of the future.

Timeline

• 7 March 2008: The domain name cinemadng.org was registered by Adobe.

• 14 April 2008: Adobe issued the press release that announced CinemaDNG.^[1][5][6][7]

• April 2009 onwards: various companies began to announce plans or even products to support CinemaDNG (see "Signs of progress").

• 10 September 2009: Adobe Labs made available pre-release versions of specifications and products for handling CinemaDNG (see "Tangible deliverables").^[8][9]

• 20 November 2009: Adobe Labs provided a "CinemaDNG Refresh" - primarily extra (longer) samples.

Signs of progress

These are evidence that CinemaDNG is more than vaporware:

• IRIDAS (April 2009): (IRIDAS Supports CinemaDNG RAW Standard): "IRIDAS ... today announced universal support for the emerging CinemaDNG standard in all of the 2009 versions of its products."^[10]
• Silicon Imaging (April 2009): (Silicon Imaging Oscar Filmmaking Digital Cinema Cameras go 3D): "The files can also be exported as a CinemaDNG sequences ... at a later time."^[11]
• Vision Research (May 2009): (in a forum): "Is a cinemaDNG support planned for the next Software release?" - "Phantom software already has support for save/convert a cine to DNG format. This is a good start to get a cinemaDNG."^[12]
• RadiantGrid (September 2009): (RadiantGrid Technologies Launches v5.0 of the RadiantGrid Platform at IBC 2009): "Important new features .... Native decoding of CinemaDNG ... from MXF Op-Atom and Op1a sources .... TrueGrid transcoding from ... CinemaDNG ... image sequences".^[13]
• Gamma & Density (September 2009): (3cP - Cinematographer's Color Correction Program): "Technical Highlights of 3cP: Support for the ... CinemaDNG image data format".^[14]

• Adobe (September 2009 and November 2009): Specification and prerelease products and other resources from Adobe Labs (see "Tangible deliverables").
• ViewPLUS (December 2009): "ViewPLUS introduced the Lumiere 4K x 2K digital camera system at the International Technical Exhibition on Imaging Technology and Equipment in Yokohama, Japan. The Lumiere camera system also includes Lumiere-REC, a software development kit (SDK) that allows users to record image data and output to movie industry-standard CinemaDNG RAW file format."^[15][16]
• INDIECAM (March 2010): (Indiecam announce to show their latest prototype indieSHUTTLE at the NAB Show 2010.) All Indiecam products offer CinemaDNG capabilities.
• Blackmagic Design (April 2011): Blackmagic Design announces support for CinemaDNG in DaVinci Resolve 8 and DaVinci Resolve Lite. Released in July 2011, DaVinci Resolve Lite is available for download at the BMD web site at no charge and offers the industry a standardized playback application for CinemaDNG files from all camera sources that can be used for camera development, on set or in the post production process.

Tangible deliverables

All of these are free and freely available;^[4] however, at November 2009 the products are prerelease versions:

• Adobe CinemaDNG Importer prerelease1 adds support to Adobe After Effects CS4, Adobe Premiere Pro CS4, and Adobe Soundbooth CS4 for reading CinemaDNG video streams in the form of MXF files and DNG file sequences. (Mac OS and Windows).^[4]

• "CinemaDNG - Image Data Format Specification (Version 1.0.0.0)" (PDF)^[2]

• "CinemaDNG Workflow - Using the CinemaDNG File Format in Cinema Workflows" (PDF)^[3]

• "CinemaDNG sample files" (directory structures in ZIP containing clips, icons, and images in both MXF and DNG-sequence forms). These are available as short samples (8 frames) and long samples (100 frames)^[4]

• A new Adobe Labs forum specifically for CinemaDNG.^[17]

Standardization

There does not appear to be any commitment from Adobe (or any other company) to submit CinemaDNG to a standards body such as ISO. However, they have repeatedly emphasized that it will be an open format, and Adobe has stated "CinemaDNG uses fully-documented, vendor-neutral, standard formats for video and imaging – DNG, TIFF/EP, and MXF. The format is unencrypted and free from intellectual property encumbrances or license requirements".^[18] It is reasonable to speculate that eventually CinemaDNG will become a formal standard, based on the history of DNG itself which has been submitted to ISO for use in the revision of ISO 12234-2 (TIFF/EP).

Rather than creating entirely new file formats, the strategy for CinemaDNG is primarily to specify how to package files and other data-sets, of existing open and/or standard formats, in consistent ways, so that not only can individual components of a movie be interchanged and archived, but so can sets of clips with all their associated video, audio, and metadata files.^[2] The emphasis is on having a systematic structure that supports the very complicated workflows, involving many stages and suppliers and software and hardware components, of movie development.^[3] The CinemaDNG specification is largely about this systematic directory structure and the requirements and constraints that ensure that individual files fit within it.

If CinemaDNG follows the same sort of path to standardization as DNG, (or indeed, PDF), there will first be a period while the specification is tested "in the marketplace" to ensure that it works in practise as well as theory. It will then be revised accordingly, so that whatever is standardized will be credible, well supported by products, and ready for immediate use. This takes years.

See also

OpenEXR

References

1. ^ ^{a b} Adobe Press Release: Adobe Starts Initiative to Develop Open Format for Digital Cinema Files
2. ^ ^{a b c d} Adobe Labs: CinemaDNG - Image Data Format Specification (Version 1.0.0.0) (PDF)
3. ^ ^{a b c} Adobe Labs: CinemaDNG Workflow - Using the CinemaDNG File Format in Cinema Workflows (PDF)
4. ^ ^{a b c d} Adobe Labs Downloads: CinemaDNG
5. ^ Macworld: Adobe plans CinemaDNG format for cinema files
6. ^ electronista: Adobe plans CinemaDNG standard for cinema files
7. ^ IT Broadcast and Digital Camera: Raw Quality Key
8. ^ Adobe Labs: CinemaDNG
9. ^ ZDNet: Adobe offers CinemaDNG format for raw video
10. ^ IRIDAS press release: IRIDAS Supports CinemaDNG RAW Standard
11. ^ Silicon Imaging press release: Silicon Imaging Oscar Filmmaking Digital Cinema Cameras go 3D
12. ^ Vision Research forum: Query about support for CinemaDNG
13. ^ RadiantGrid press release: RadiantGrid Technologies Launches v5.0 of the RadiantGrid Platform at IBC 2009
14. ^ Gamma & Density press release: 3cP - Cinematographer's Color Correction Program
15. ^ Press release in Forbes: ViewPLUS Introduces Lumiere 4K x 2K 60 FPS Digital Camera System
16. ^ ViewPLUS: Lumiere
17. ^ Adobe Labs forum: CinemaDNG
18. ^ Adobe Labs: CinemaDNG File Format