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The Making-of 2013

Presentation: The DCI Manufacturing Process and Digital Cinema Distribution

With Tommaso Vergallo, Digimage Cinéma Paris

Introduction & DCI Specifications

The Digital Cinema Initiatives (DCI) was created in 2002 and is a joint venture of six Hollywood majors. DCI’s primary purpose is to establish and document voluntary specifications for an open architecture for digital cinema that ensures a uniform and high level of technical performance, reliability and quality control. The latest version is 1.2 and dated March 2008.

The group has set specifications for the digital master and digital distribution formats, but it did not provide standards for production and post-production.

Formats & Ratios

The formats defined are:

All other formats (4:3, 16:9 etc.) have to enter into these frames – the remaining space is left black.

The frame rate standard is 24fps, however, 25fps is possible depending on the player. In the future more frame rates will be available.

The DCI Mastering Steps

The generation of a Digital Cinema Package (DCP) consists of various steps and phases:

  1. Digital Source Master (DSM): any source of digitized images .dpx or .cin in RGB format with any pixel matrix (spatial), frame rate (temporal) and bit depth.
  2. Digital Cinema Distribution Master (DCDM): it’s a complete and standardized format to communicate movies, for example, between studio and post-production. To serve as a master and exchange format, the DCDM should be saved in very high quality with the resolution, frame rate and audio channel distribution of the later DCP. This is the format to be used for archiving with LTO tapes for example.
  3. Lossy Compression Stage (JPEG2000): for saving storage space and bandwith, the size of a DCP must be reduced so that it can be trsanported, saved and displayed without great efforts. In order to do so, the DCP will be converted to 12bit (X’Y’Z’) and then encoded with JPEG2000. The audio data will not be compressed.
  4. Digital Cinema Package (DCP): the last stage of a DCP creation, audio and J2C encoded image files will be wrapped (either encrypted or unencrypted) in the MXF format as the DCP’s content delivery format.
  5. The DCP Structure: The DCP is a set of files where soundtrack and videotrack are separated but encapsulated in MXF files and accompanied with the set of XML descriptor files (containing digital signature of each file of the package) and subtitles. MXF files of a DCP can be encrypted, in this case the package author must provide a key (KDM) to allow a DCP player, such as the exhibitor, to play the feature during a given period and in a given language version.

New mastering systems have considerably accelerated the process. All necessary steps from DSM to DCP can be created in a single system which prevent time consuming transfer processes through the use of many different components.

DCP Distribution

The delivery of the DCPs is either physical via hard drive or virtual/dematerialized (if the theatre is equipped and connected) via specific networks like SmartJog or GlobeCast.

The distributor pays the post-production house for:

Because of the encryption of DCPs and digital signatures contained in the package description files, the laboratory that manufactures the package is the only one who can provide a key to unlock screening for a given server. The number of digital devices constantly increasing, it has soon become necessary to have a database of security certificates installed players, to provide them KDMs.

For a 500 print release, the post house may only produce 80 DCPs, the rest is transferred via download since only 15-20% of cinemas need a hard-drive. Thus the distributor is saving 80 to 90% on a release while the exhibitor has to invest in the acquisition, installation and maintenance of new servers and projectors.

Therefore the Virtual print Fee (VPF) has been invented as a fee that the distributor pays to the exhibitor, or a third party investor, each time the latter screens a film. Through the VPF, the distributor shares a part of his savings with the exhibitor, enabling him to pay back the digital equipment which may have been financed through third parties. Third parties are investors (often funded by Hollywood Majors) who invest in the digitisation of cinemas and who will be paid back through the VPF. There is however a danger seen by many art house movie theatres: the third party investors could put pressure on art house cinemas resulting in a change of programming – their goal being to play more mainstream movies, thus generating as much VPFs as possible, to accelerate pay-back to the third parties.

In this model, the producers are still not getting their share. On the contrary, they might be forced to pay for two or even three types of delivery: the 35mm print, the DCI-DCP, and sometimes also for an E-Cinema delivery in Digibeta.

The Making-of 2013

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