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Frequently asked questions

How can I deliver files to Cinelab ?

  • For all deliveries up to 20GB, you can use this link.
  • The number of uploads is unlimited.

What type of hard drives are accepted at Cinelab?

  • NTFS, HFS and Linux formats are accepted. Hard drives must have Thunderbolt or USB3 connections.
What is a DCP?

  •  A Digital Cinema Package (DCP) is the equivalent of the digital cinema projection copy that was in the form of 35mm film reels in traditional cinema
  • A DCP consists of a set of computer files (images, sounds, subtitles, metadata …) finalized on hard drive. These are to be stored and played in the projection booth with a DCP server coupled to a digital projector
  • A DCP can be mastered in 2K or 4K, Scope or Flat, and 2D or 3D-stereo
  • Technically speaking, a DCP is a collection of assets, listed in a PackingList document, supported by an AssetMap document

From what material can you make a DCP?

  • CineLab creates DCP from your DCDM (Digital Cinema Distribution Master). This is an hard disk (or LTO) including all files and metadata specially prepared for DCP mastering (DCI color space, gamma 2.6, resolution, framing..)
  • We can also convert any type of file, HD formats and codecs (such as ProRes-HQ) to a master DCDM. DCP mastering from standard resolution sources (PAL, NTSC …) is not recommended because of their low quality and that they require, in addition most of the time, a de-interlacing operation

What are the steps in making a DCP?

  • After transfer to our servers image & sound material is checked and prepared
  • The image is possibly cropped to  SCOPE (2.39:1) or FLAT (1.85:1) formats, depending the framing reference chosen for the project
  • After proper XYZ and 2.6 gamma transforms, image is then encoded to JPG2000 which is a “lossless” high quality codec
  • The image sequence and different sound tracks are then encapsulated in MXF format. Unless specifically requested, acces to these files is protected by the creation of KDM security keys (Key Delivery Message)
  • Metadata, such as different versions of subtitles, are prepared and verified to be integrated into the “composition play list(s)” containing the various image and sound sequences
  • Finally takes place the DCP mastering itself, and files naming according to the ISDCF standards
  • Each DCP is checked on our digital cinema Doremi server, with Barco 2K digital cinema projection . A QC sheet accompanies each DCP copy

What is DCP versioning?

  • DCP versioning is the process of adapting an existing DCP to other language versions
  • Our mastering software allows us to “un-wrapp” any DCP and add, remove or modify audio, sub-titles, or image data. For example we can add an distributor’s logo before the main movie, or replace a VO mixing by a dubbed version
Can a DCP contain multiple versions of a movie?
  • Yes, a DCP can contain multiple CPL (composition playlist) eg corresponding to different language versions of a film. This is called a “Multi CPL” DCP.
  • In the case of variations in the subtitles, each CPL will read the same image/sound media (copied once to disk), but adding specific metadata for the desired language.
  • If the DCP is encrypted, the projectionist will have access only to language versions for which he has a KDM.
  • It is also possible to copy multiple DCP (complete) of different versions or even different movies on the same disk.
What is a CompositionPlaylist (CPL)?
  • In Digital Cinema a composition (or CompositionPlaylist) is a timeline consisting of at least one Reel which in turn references the required assets for content playback. Usually a Reel will reference MainPicture and MainSound elements, at least.
  • There can be elements for subtitles, closed captions and markers as well.
  • Another way to think of it: A composition defines precisely what will be seen and heard in the theatre. Much like the timeline of an editing application would define what’s to be seen and heard on the monitor in master playout.
What is a “Supplemental” or “Version File” DCP?
  • A Supplemental (VF) DCP is a complementary DCP sent to complete an existing DCP (OV) already ingested on a cinema server.
  • It contains one or more new composition lists (CPL) referencing to existing DCP medias, but bringing variants, such as the addition of reading a distributor logo before the movie, or the use of another subtitles version, for example.
  • In the simple case of an additional subtitling version, it has the advantage of being very light and can be easily sent to the venue.
What is a KDM?
  • KDM is an acronym for Key Delivery Message and it does pretty much exactly that: Deliver 1 or more content keys to a target device.
  • The content keys delivered will be referenced by a specific composition. In addition it tells target devices about the validity range for the delivered content keys. Meaning from when to when devices are allowed to use those content keys.
  • KDMs are required to be digitally signed.

“Interop” ou “SMPTE” DCP format ?

  • Two kind of DCP format currently coexist: Interop and SMPTE
  • Unless special request Cinelab creates SMPTE DCP as it’s the only official DCP “standard”. Interop format (doomed to disappear) itself being based solely on DCI “recommendations”    ISDCF TimelineForAccessibility.pdf
What are the differences between “Interop” and “SMPTE” formats?

Whatever picture and sound quality are identical for both formats, SMPTE DCP brought several changes:

  • more frame rates:  in addition to 24 and 48 frames per second, there are now ways for 25, 30, 50 and 60 frames per second
  • audio channels and their assignment on the speakers in the room are modified
  • subtitles are handled differently
  • XML namespace used is different
  • the requirements for the validation of content, KDM and certificates are different

How are formatted DCP’s hard drives?

  • SMPTE standard states that DCP’s hard drives must be formatted in EXT3 Linux (or EXT2)
  • Although some servers are sometimes able to recognize drives formatted to other formats (NTFS, HFS…), it is strongly NOT RECOMMENDED to send no- “DCI compliant” formated drives, as they may not be recognized by all types of servers (Dolby, Barco, Doremi, etc …)

Can I copy a DCP myself?

  • It is not advisable to try to connect, mount, list or edit a DCP disc on a system not dedicated to DCP reading or mastering
  • The slightest change in the name or file size will make any DCP unreadable, because safety tests conducted during ingests by cinema servers will be negative
  • Copying a DCP disk to another disk may also cause slight variations in the size or file names, making them unreadable
  • We recommend to ALWAYS check your DCP on a DCI Compliant server AND projector before shipping to theaters or festivals

 

Usefull links

CineLab – Digital cinema equipments
Assimilate’s SCRATCH Showreel 2012
Doremi Digital Cinema Servers
Barco Digital Cinema
Avid DS Nitris

Digital cinema tools & community
Assimilate’s SCRATCH 7 video tutorials 2012
Arri LUT Generator
Red cameras users forum

DCP Mastering
Inter-Society Digital Cinema Forum (ISDCF)
Digital Cinema Naming Convention
Digital Cinema Initiatives (DCI)