What's a D.C.P. ?
Digital Cinema Package:
A collection of files that meet the standards of Digital Cinema and can be projected by a DCP server.
What does a DCP look like and how is it organised?
It is a directory of files containing audio and video content in MXF format, and metadata XML files containing instructions on how to read the audio and video content. Subtitle files are in XML or MXF format.
How large is a DCP?
For a trailer, less than 8 GB; for a short film, less than 64 GB; for a medium-length film, less than 128 GB; for a feature film, less than 300 GB... in general
Is DCP a Hollywood invention?
Basically, yes, it's 7 Hollywood studios joining forces to create the DCI... and impose their standard on the rest of the world, successfully.
The studios created a completely controlled ecosystem. They distribute their films only in locked form, accompanied by decryption keys only for the networks and devices that they trust. To date this system has not been successfully hacked.
What makes DCP unique is that it is based entirely on open technology, such as JPEG 2000, MXF packaging and SMPTE standards.
This open system benefits everyone, and a DCP that is well-mastered at 24 fps will be playable everywhere.
Will the DCP format endure?
Now that DCP has swept away film, and while all its foundations are open source (jpeg-2000, mxf encapsulation, xml, etc.), the standard is set to last. Even in the distant future, it won't be very complicated to read today's DCPs, even on machines and programming languages that don't yet exist. The sources are free, the standards are available, and a programmer will soon be able to make the foundations compatible. It's a guarantee of longevity.
Encryption poses a threat for film storage; without the decryption key, the DCP is nothing but an indecipherable series of zeros and ones.
Regarding storage media, a DCP is as vulnerable as the media on which it is stored, as the digital storage media of today is not designed to last for decades. To counter this vulnerability, Charbon offers electronic DCP archiving.
DCI stands for...
Digital Cinema Initiative:
The consortium of seven American studios that created the Digital Cinema standard: Disney, Warner Bros, Universal, MGM, Paramount, Sony and Fox.
CPL stands for...
Composition Play List:
A set of sound, image and subtitle files put together to form a version of the DCP.
You will need a different CPL for each version (for example: 1 CPL sound VO, 1 CPL sound VO with French subtitles, 1 CPL sound VF, etc.).
Unlike on Blu-ray or DVD, the projectionist does not have access to a menu from which to choose sound, image and subtitles separately. The projectionist simply has to choose the correct CPL.
KDM stands for...
Key Delivery Message:
The decryption key that unlocks an encrypted DCP for a given theater for a certain period of time.
DKDM stands for...
Distribution Key Delivery Message:
A KDM issued not for a projection system but for a post-production system, which can then decode the DCP, modify it, or in turn issue other decryption keys.
DCDM stands for...
Digital Cinema Distribution Master:
it's the master, already up to digital cinema standards (colour space XYZ' colour space, gamma '2.6'), but not yet compressed in jpeg-2000.
The DCDM is requested by certain institutional players (including the Fédération Wallonie-Bruxelles in Belgium) as a legal copy.
In theory, a DCDM is an intermediate product from which the DCP the DCP is generated.
In practice, in some laboratories, including Charbon, the DCP is generated directly from the calibration, without any intermediary, to make the most of its quality.
DCDM is not an ideal medium for digital preservation of films, as it is films, because it is 10 times heavier than a DCP and not nearly as standardised/normed.
It takes the form of a series of images (tif, dpx, etc.) and associated sounds (wave) in one or more folders. associated sounds (wave) in one or more folders, which may or may not be on a hard disk.
LUT stands for...
Look Up Table:
A colour conversion table that shows, on a given medium (such as an HD projector), what the displayed image would look like on another medium (such as a DCI projector), or that keeps the colours constant when changing the medium.
3D LUTs have three dimensions.
Smpte stands for...
Society Of Motion Picture & Television Engineers :
An organisation that recommends standards for the film and television industry. The SMPTE revised and developed the strict standards of the DCI consortium in order to create much more universal - and therefore lasting - standards. The standards did not become stable until 2011 and have taken some time to replace old Interop practices.
SMPTE standards are used for DCPs, KDMs and subtitles.
In the Digital Cinema world, Interop is the opposite of SMPTE.
What is Interop?
Interop is short for "interoperability" and is a set of practices followed by people who work in Digital Cinema to fill the gap left by the temporary lack of worldwide standards.
Although it has now been overridden and replaced by SMPTE standards, Interop has endured. It has all but disappeared for KDMs, but remains very widely used for subtitles (referred to as Interop/CineCanvas) and is still used for DCPs.
It is not uncommon to do a SMPTE DCP with a SMPTE KDM and Interop subtitles.
What is JPEG 2000?
The highly effective compression algorithm at the heart of DCP. Compression is achieved without a quality loss that is visible to the naked eye.
What is a DCP ingest (or import)?
  • This is the action of copying a DCP from its medium (hard disk, USB key, Internet, etc.) to the DCP server.
  • The ingest is mandatory, as the DCP cannot be played directly from its storage media.
  • During the ingest process, the integrity of the media is verified and the slightest anomaly cancels the import.
Supplemental DCP?
This is a DCP that adds one or several versions to an original, already mastered DCP
The additional versions change the sound (e.g.: dubbed French version) and/or subtitles (e.g.: OV subtitled in French…).
Supplemental DCPs do not contain the media they have in common with the original DCP. This has two consequences:
  • It is possible to send a supplemental DCP of a subtitled version by email, for the supplemental DCP contains neither audio nor video and is therefore very light (the projectionist therefore has to put the supplemental DCP on a USB flash drive to ingest it into his server).
  • The l'ingest of the original DCP must be done before that of the supplemental DCP.
Can a DCP be made from a DVD, Blu-ray, Beta, DV...?
Yes, with even better results than the original media, since everything that is in standard definition will undergo a hardware upscale to HD.
Can a DCP be made from an interlaced image?
Yes, with very good results, through advanced techniques:
  • If the image is in SD it will undergo a hardware upscale to HD
  • The HD image will then be specially deinterlaced to maintain the full resolution of non-moving areas
Can a DVD, Blu-ray, HDCAM... be made from a DCP?
Yes, with very good results, since a DCP is a very high-quality master.
What resolutions does DCP offer?
The image resolution of a DCP projected in 2K is 1998x1080 (1.85 aspect ratio, "flat mode" projector), or 2048x858 (2.39 aspect ratio, "scope mode" projector). In 4K the resolution is 3976x2160 (flat) and 4096x1716 (scope).
Ratios are maintained by padding the image with digital black. 2K resolutions are:
  • 1440x1080 for 4/3 (black borders on the sides)
  • 1792x1080 for 1.66 (black borders on the sides)
  • 1920x1080 for HD 1.78 (black borders on the sides)
  • 1998x1080 for 1.85 (no black borders)
  • 2016x858 for 2.35 (black borders on the sides)
  • 2048x858 for 2.39 (no black borders)
How to avoid a black border?
  • The width of the image must correspond to the width of the chosen standard: 1998 for 2K flat, 2048 for 2K scope, 3996 for 4K flat, 4096 for 4K scope
  • Or the height of the image must correspond to the height of the chosen standard (1080 for 2K flat, 2160 for 4K flat, 858 for 2K scope, 1716 for 4K scope)
  • Otherwise the DCP projector adds digital black to produce the supported resolutions
  • Many screens are scope (2.39): when they are used in flat mode (1.85), the image does not fill the whole screen, there are black borders on the sides. This black results from an absence of projection and is deeper than the digital black added by the projector.
For letterbox films?
  • Some films are delivered for DCP mastering with black borders in the master. This is the case, for example, for 1.85 films mastered in HD (1.78 ratio): they have black borders at the top and bottom.
  • If such a film was mastered in DCP in this state, one would obtain an image that had black borders at the top and bottom (those present on the master) and at the sides (those added by the FLAT digital projection for a horizontal resolution of less than 1998px).
  • One must therefore zoom in on the image so that one of the true dimensions of the image corresponds to one of the dimensions of the DCP. For 1.85 mastered in HD, the true resolution is 1920x1038, and it must be zoomed to obtain 1998x1080: this is a zoom in of 4%, done during the DCP mastering.
2K or 4K?
4K projection is still very rare in Europe, even though the industry, which would like to continue selling projection systems at the same rate, is touting it very aggressively.
On a 10-metre wide screen, each pixel measures 5mm in 2K and 2.55mm in 4K. At a viewing distance of 6 metres, the human eye will discern details of 2mm (with perfect vision, the eye has resolving power of 30 cycles per degree)
If 4K projection becomes widespread, films currently being shot in 4K would be well-advised to make 4K DCP masters.
Does 4K technology make DCPs and 2K DCP servers obsolete?
No, because a 2K DCP can be played on a 4K server, and a 2K server can play a 4K DCP... in 2K resolution.
24 or 25 images per second?
Originally, the DCI catered only for 24 images/second. It was not until later that the SMPTE set many other rates, including 25. The SMPTE standard is becoming more widespread.
It is estimated that over 85% of DCP servers are able to playback 25p content.
Should films shot at 25 images per second be slowed down?
It would be unfortunate for a film shot at 25 fps to be systematically slowed down for only a few incompatible projectors.
The best solution is to make a backup version at 24 fps in addition to the normal version at 25 fps, which Charbon systematically offers to all clients.
How is a film slowed from 25 to 24 frames per second?
The images do not require any particular processing, but the sound must be slowed by 4%.
  • Either a mixing studio harmonises it, offering the advantage of not changing the pitch of the sound, but with the disadvantage of possibly adding artifacts;
  • Or the sound is slowed, which offers the advantage of being more economical, without artifacts, but the disadvantage of dropping the tone by nearly a half pitch.
    Listen to an original sound trackand its slowed version
Is it better to embed the subtitles in the image of a DCP?
It is not obligatory, as DCP servers generally support either Interop/CineCanvas subtitles or SMPTE subtitles, and Charbon always puts both standards on the DCP.
Embedding the subtitles in the image ensures that the subtitling will never pose a problem whichever server is used and allows for complete control of text formatting.
Keeping the subtitles separate makes any subsequent modifications and versioning easier, in addition to making the subtitles stand out better against the projected image.
To summarise, embedded subtitles are the safest solution, but separate subtitles are the solution with the best price/reliability ratio.
What is Interop/CineCanvas subtitling?
It is the old subtitling standard, still used by the majority but doomed to obsolescence.
Subtitles are added by the projector from an subtitle XML file sent by the network.
It is a proprietary technology developed by Texas Instruments.
What is SMPTE subtitling?
It is the new subtitling standard, destined to replace Interop.
The subtitles are added by the DCP server from an subtitle MXF file.
How can I have total control over the formatting of DCP subtitles?
Either by engraving them in the image, or by inlaying subtitles in the form of images rather than text.
Charbon is one of the only laboratories in the world to render its SMPTE subtitles as images, giving it total control over their appearance and all the flexibility of DCP versioning.
I had a DCP made with a subtitled version. Why did I receive 5 versions?
Charbon always recommends making a backup version at 24 fps for films shot at 25 fps. Therefore there are two base versions: 1 version that meets the recent SMPTE standards at 25 fps and 1 backup version using the old Interop standards at 24 fps.
Likewise, in subtitling there are two standards that coexist: the recent SMPTE standard, which is sure to endure, and the old Interop standard, which is becoming obsolete. Charbon always puts both standards on the same DCP.
So in all there is:
  • The SMPTE version at 25 fps without subtitles
  • The SMPTE version at 25 fps with SMPTE subtitles
  • The SMPTE version at 25 fps with Interop subtitles
  • The Interop version at 24 fps without subtitles
  • The Interop version at 24 fps with Interop subtitles
This optimises the chances that the DCP is projected properly everywhere.
What is an encrypted DCP?
It is a DCP that was encrypted at the time it was created.
DCP projections must be authorised on a case-by-case basis, for a specific CPL and theatre, using a KDM
Without a KDM, the DCP is indecipherable.
Who can issue a KDM?
  • The lab that created the encrypted DCP.
  • The customer if in possession of a dkdm (unless otherwise requested, Charbon always gives its customer a dkdm)
  • An external kdm service provider, to which a dkdm was issued.
My DCP is encrypted. How can I ensure that it will not become indecipherable?
Charbon always delivers the decryption key, which enables the generation of other keys (the DKDM).
If need be, the SSL certificates targeted by the DKDM are created for the client.
Thus clients can carefully archive the DKDM and certificates, in the knowledge that if necessary they will always be able to decrypt the DCP.
My DCP is encrypted. How can I authorise projection?
By issuing a specific KDM for the CPL/DCP server combination.
Charbon offers its clients unlimited generation of KDMs online, free of charge.
My DCP is encrypted. How can I modify it?
In order for Charbon to be able to modify your encrypted DCP that was made elsewhere, a KDM must be issued for the Charbon certificate.
My DCP is encrypted, but I am unable to issue a KDM. What can I do?
The DCP is then indecipherable and cannot be modified.
KDM Tool
What is the short address for the KDM tool?
What does the KDM tool do?
It authorises the projection of your encrypted DCP made at Charbon, at a certain theatre, for a certain period of time
Is the KDM tool reliable?
  • a 256 bit SSL connection (the same used for online payments)
  • password protected access
  • no agent external to Charbon Studio intervenes in the administration of the system
  • the certificates proposed come only from trustworthy databases
What is a certificate?
It is a digital file (.crt or .pem) unique to each DCP server. A KDM issued for a certain certificate can only be used by the DCP server corresponding to this certificate.
Where do the certificates in the KDM tool database come from?
From CNC, Ymagis, Doremi, Qube, XDC/Dcinex, GDC, Dolby, Sony, and research carried out by Charbon Studio with exhibitors.
The KDM tool in figures
  • countries
  • theatres
  • auditoriums
  • certificates
Are all the digital theatres in the world in the KDM tool?
All those for which we have obtained details. If you need to add auditoriums or a whole data base, contact us.
Moreover, the certificates not linked to a theatre can be used via the serial number of the DCP server to which they correspond.
Finally, you can load the certificates you need into the KDM tool yourself.
The process
How long does it take to create a DCP?
One week following delivery of all components (image, sound, subtitles).
If need be, you can purchase the "rush" option and have the DCP delivered within 48 working hours.
What process does the HD image undergo to be transformed into a DCP?
  • In a DCP, colours are expressed in XYZ. The colours of an HD master are generally expressed in RGB. They must therefore be converted from RGB-HD to XYZ.
  • A gamma correction must also be carried out, because the HD gamma is 2.2, whereas the DCP gamma has been standardised at 2.6.
  • The nominal luminosity is 48 candela per square metre and does not need to be changed.
  • The source image will be resized as necessary to match at least one of its dimensions (width or height) to one of the two resolutions of the DCP.
Can a DCP be made for free? How does it turn out?
There are free tools for creating DCPs, such as OpenDCP.
By default, a "free" DCP will have reduced functionality (versioning, encryption) and possibly colours that are not as deep. It all depends on the quality of the solution used for the colour conversions.
Whether free or purchased, all of the tools on the market share much of the same open source code. It is not so much the tool itself that is important but the care and expertise with which it is handled, and the workflow.
What system does Charbon use for DCP mastering?
Charbon uses its own combination of purchased tools (CineSpace, DaVinci Resolve, LightSpace), tools that were developed entirely in house (subtitling, versioning, KDM creation), tools that were adapted using open source code (digital cinema tools) and open source tools (asdcp-test).
What determines the quality of a DCP?
The quality of its DCDM.
Charbon always masters its DCDM in 16 bits to take full advantage of the 4096 shades of red, green, blue and grey available in the DCP. In order to have accurate, deep colours, the RGB-HD to XYZ colour conversion is carried out with a specially designed 3D LUT.
How is DCP colour fidelity ensured?
  • Charbon uses a specially designed 3D LUT, which ensures perfect colour fidelity when converting from HD to DCP.
  • We also have an inverse LUT, which is used to go from DCP to HD.
  • Because the DCP colour space is larger than that of HD, the process is completely transparent. One can pass from HD to DCP and then from DCP to HD with no significant difference.
How many versions are necessary to obtain a DCP with perfect colour fidelity?
Only one, regardless of where the film was colour graded, provided that it was done with a properly calibrated HD projection.
Because the DCP colour space is larger than the HD colour space, we can obtain results in DCP that are completely true to the HD master.
What can be done if the colour graded image provided to make the DCP is questionable?
It is possible to do a quick pre-mastering at the studio. The image projected at the studio is faithful to the image seen in the cinema.
How heavy will my DCP be?
DCP standards specify a limit of 250 Mbits per second for the image, or 31 MB / second, or 1.8 GB per minute, or 111 GB per hour.
This is less than the Prores 4444 (330 Mbits / second), and slightly more than the Prores HQ (220 Mbits / second).
But DCP uses JPEG-2000 compression, which is much more effective than Prores at compressing the image faithfully and lightly. Not only will there be no loss from a Prores HQ or Prores 444 master, but the DCP may even be much lighter than a Quicktime master, especially when large extracts of the film are taken from small cameras.
At Charbon, colour-graded films are released directly in DCP, without going through a quicktime intermediary. The result is heavy DCPs... and faithful ones!
What determines the reliability of a DCP?
  • the care taken in its manufacture: at Charbon, integrity checks are automated and full human vision is systematically applied
  • The quality of its media: Charbon recommends high-quality server disks ("server-grade" or "enterprise-grade").
Why are server-grade disks preferable?
  • It only takes one error when reading one of the 2400 billion bits comprising a feature-length DCP (300 GB) for the ingest to fail. It is not a bug; it is a characteristic of DCP servers. The integrity of the media is systematically verified during the import process, and the DCP is rejected when the slightest anomaly is discovered.
  • A consumer disk has one chance in 100,000 billion of having a reading error in each bit. A server-grade disk is 10 times more reliable.
  • The probability of an ingest failure is therefore 2.5% for a consumer disk (formula), as compared to 0.25% for a server-grade disk (formula).
What type of media is the most reliable?
A DCI disk. See the DCP Media Guide.
What is a disk image of a DCP?
This is a clone of DCP media, saved as an ".img" file. .img" file.
With the right tool, this disc image can be reproduced on a new new DCP media, simply and reliably.
How do I reproduce a DCP on a Mac?
Charbon Studio a développé pour ses clients "CharbonDCPImage", pour reproduire les DCPs avec simplicité et fiabilité.
There are only 2 settings to make:
- sélection de l'image disque du DCP (fournie par Charbon)
- media selection (USB key, hard disk, etc.)
How do I reproduce a DCP under Windows?
Avec Win32DiskImager.
It's easy to use, with just 2 settings to make:
- sélection de l'image disque du DCP (fournie par Charbon)
- media selection (USB key, hard disk, etc.)
How reliable is a DCP reproduced from a disc image?
Excellent, because all the work done to ensure that the DCP complies perfectly with standards is preserved.
The reliability of the reproduction therefore depends entirely on the the reliability of the medium chosen (which is a good reason for to use high-quality media, and in particular not cheap cheap USB sticks).
On the other hand, reproduction from a disk image does not include integrity control, unlike reproduction in the studio. studio reproduction.
But I thought that neither Mac nor Windows recognise DCP?
It's true, by default they can't read a DCP disc, but they can still reproduce it reliably, from from a disc image.
This is the advantage of the technique of 'cloning' from a disk image: the entire DCP disk is cloned, the computer does not need to recognise what it contains.
Difference between cloning and reproduction at the studio?
At the studio, we systematically carry out a full data integrity check data integrity (and once out of every 30 times on average, correct a disk error detected in this way), whereas with cloning does not.
Apart from that, on the Mac, with CharbonDCPImage: there's no difference.
On Windows, with Win32DiskImager :
  • for DCP disk images made before 02/01/2016 : cloned DCPs do not have a partition table, and will "only" work with 95% of the world's servers.
  • for DCP disk images made between 02/01/2016 and 05/18/2016: you will need to use media of 256GB or more. otherwise no difference.
  • from 05/18/2016, no difference,
I'd love a disk image of my DCP!
  • For a DCP master made at Charbon from 01/01/2015 : it's included!
  • For a DCP master made at Charbon before 01/01/2015 : it is the same price as a reproduction.
  • For a DCP master made by our colleagues, the cost is the price of a reproduction + the price of an "import DCP made import".
I'd love to test my DCP reproduced from a disk image!
Aucun problème, envoyez nous votre première reproduction, nous en testerons un ingest complet, sans frais (hors frais de ports).
I'd love to try out disk image cloning with a lightweight DCP! !
CHARBON-SON-51_TST_F-178_XX-XX.img est une image disque légère, à utiliser avec CharbonDCPImage.
It is a surround sound test DCP.
My Mac won't open CharbonDCPImage?
Apple thinks it's a good idea to prevent the launch, by default applications downloaded from anywhere other than their App Store".
You will then see a message like this: Impossible to open "CharbonDCPImage.app", because this app has not been downloaded from the Mac App Store.
What needs to be done:
Are you breaking the market by making it easier to reproduce DCP?
No, our job is not to sell discs with data on them. data on them, it's about finishing films and giving them the means the means to reach their audience.
The more reliable and accessible the reproductions, the more independent film holders are autonomous in their reproductions, the more everyone, including us, can relax. included.
I am unable to read the DCP mastered by Charbon on my computer. What is the problem?
Charbon follows DCI specifications and delivers DCPs on Linux formatted disks (Etx3).
Mac OS and Windows cannot read the disk, which is fortunate as it prevents them from being corrupted.
Can I have a copy of the DCP on my original hard drive?
Yes, as a matter of fact Charbon always copies the DCP onto the original disk (provided by the client to deliver the digital materials).
The disk must have been formatted in HFS+ or Exfat (or else be able to be formatted by Charbon).
Can I deliver my original hard drive to the cinema?
No. The copy of the DCP is made on the original disk to facilitate backup and the future duplication of the DCP.
To do an ingest, the DCP servers need a specially prepared disk.
How should a disk be prepared for DCP delivery to a cinema?
The DCI specifications, scrupulously followed by Charbon, require the delivery of a disk formatted in Ext3 (Linux), with a single 'MBR' partition.
In practice, the NTFS format for Windows disks is widespread enough.
The DCP file is located at the root of the hard drive.
What operations are involved in DCP duplication?
In order to reproduce a DCP, Charbon partitions the media, formats it in Ext3, copies the data, and conducts a complete integrity verification of the copied data in order to be certain that the DCP is identical.
I don't know which version to project on a DCP Charbon?
Charbon systematically delivers subtitled versions in both the old Interop standard and the new Smpte standard.
If your installation allows the projection of SMPTE subtitles, this is the version to choose.
For @25 films, Charbon supplies a backup @24 version on request: this should only be used if your installation does not support 25 frames per second.
Why choose SMPTE image subtitles?
Subtitles in the form of images rather than text allow total control over their positioning, size, thickness and softness of the border, etc., and avoid encoding problems.
I've uploaded a DCP via FTP and my server doesn't recognise it
FTP clients can corrupt xml files when set to "ascii" mode.
Solution: use SFTP instead or set your client to transfer in binary mode (for Filezilla: Transfer -> Type -> Binary menu). Or download the DCP using FTP directly from your DCP server.
I can't manage to ingest a DCP made by Charbon
Charbon complies 100% with DCP standards, systematically checking all its masters and the integrity of all its copies.
In this case, ask the production company or distributor for a new copy, or if the DCP was downloaded online, start a new download.
If you have any doubts, to help us identify the problem, please contact info@charbon-studio.com :
  • - DCP server model
  • - Ingest method (CRU, Esata, USB, Internet...)?
  • - What type of media (disc, USB stick, intangible, etc.) and from what source?
  • - Have other ingestion methods been tried?
  • - Does the DCP server react when a disk is plugged in?
  • - does ingest start?
  • - does the CPL read, and if so, when does the problem arise?
  • - name (AnnotationText) of the CPL that does not read as expected
  • - uuid of the CPL which does not slit as expected
  • - what error message is displayed? (please take a photo of the screen)
I've ingested a DCP but I don't see it in my list of content.
  • Once the ingest is complete, you need to refresh the list of content (which is done on a Doremi DCP-2000 by clicking on the green arrow in CineLister).
  • Then look for the DCP in the right category:
    • TST" DCPs go into "tests
    • SHR" DCPs go into "Short Movies".
    • FTR" DCPs go to "Feature Films".
    • TLR" DCPs go to "Trailers".
  • On the Doremi DCP-2000, you can perform a manual search by clicking on the magnifying glass, then "custom", and entering a few letters of the DCP title.
  • If, after refreshing the list, the content does not appear in any of the categories and the "custom" search does not show it, it is probably because, despite appearances, the ingest has not been carried out correctly.
How do I export logs from a DCP-2000?
  • Menu" / "Doremi Apps" / "SM Log Viewer" button
  • Select the lines of logs you want to export (don't hesitate to take more than just the time you are trying to analyse, as the logs contain no confidential information), then click on "Export".
  • A simple method for recovering logs is to save them on a USB key formatted in FAT32.