What is a Digital Cinema Distribution Master / DCDM?

What is a Digital Cinema Distribution Master / DCDM?

7. June 2016by Julius Waltenberger in DCinema FAQs tagged , , ,

A Digital Cinema Distribution Master / DCDM

is a prestage format in the process of creating a DCP / Digital Cinema Package. The DCDM is mostly archived alongside with the DCP, to act as a source format for future purposes (remastering / ancilliary markets, localised versions…)

A DCDM contains all data needed for the creation of a Digital Cinema Package / DCP (picture, sound, subtitles, metadata) in uncompressed and unencrypted form.

Picture and sound data must be formatted according to  DCI Specs .

Picture:
Flat: 1,85:1 = 1998:1080 Pixel
Cinemascope: 2,35:1 = 2048:858 Pixel

Sound:
Broadcast Wave file format (.wav), see ITU Tech 3285
version 1 (PCM WAVE) 24bit 48 or 96 kHz 5.1.

Meanwhile, many archives and film funding agencies also require the submission of a DCDM / Digital Cinema Distribution Master in addition to the DCP. This includes, for example, the German Federal Film Archive (Bundesarchiv), which even has a special specification for the technical credits of the individual files/reels. We will be happy to create your DCDM in accordance with these specifications, including technical credits and validation report in BagIt format, and send it to the Federal Archive.

If your funding guidelines stipulate the provision of an accessible version (subtitled version for the hearing impaired HoH / audio description for the visually impaired VI), we will be happy to create this in collaboration with you or as a full-service contract with proven partners.

In exact terms:

A set of DCDM files (image, audio, subtitles, etc.) contains all of the content required to provide a Digital Cinema presentation. The DCDM provides two functions, an interchange file format, and a playback format that is directly sent from the Media Block to the projector (this is referred to as DCDM*). For use in interchange, the encoding process can be performed in real time or non
-real time. For use in playback, the DCDM* is logically required to playback in real time.
Metadata within the DCDM provides a method to synchronize image, audio and subtitles. This method is used to synchronize the tracks in order to maintain frame -based lip sync from the beginning to the end of a presentation. This is different from the requirement to synchronize the system clocks of different pieces of equipment to run at consistent frequencies. The first part addresses the packaging of the picture, sound and subtitles in such a way as to establish and maintain a timing relationship between all these tracks of essence.

For more details, see Appendix DCI Specification Chapter 3 “DIGITAL CINEMA DISTRIBUTION MASTER” (EN).

PDF attachment:

DCI Spezifikationen v143 2023.pdf

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