Digital Cinema Package

A Digital Cinema Package (DCP) is a collection of digital files used to store and convey Digital cinema (DC) audio, image, and data streams.

The term has been defined by Digital Cinema Initiatives, LLC in their recommendations for packaging of DC contents. General practice adopts a file structure that is organized into a number of usually multi-gigabyte size Material eXchange Format (MXF) files, which are separately used to store audio and video streams, and auxiliary index files in XML format.

The MXF files contain streams that are compressed, encoded, and encrypted, in order to reduce the huge amount of required storage and to protect from unauthorized use. The image part is JPEG 2000 compressed, whereas the audio part is linear PCM. The adopted (optional) encryption standard is AES 128 bit in CBC mode.

The newer SMPTE standards are used to conform the recommendations among different tool vendors and producers. Interop, the legacy DCP standard, is still required to be supported by DCP players.

Technical specifications

The DCP root folder (in the storage medium) contains a number of files, some used to store the image and audio contents, and some other used to organize and manage the whole playlist.

Picture MXF files

Picture contents may be stored in one or more reels corresponding to one or more MXF files. Each reel contains pictures as MPEG-2 or JPEG 2000 essence, depending on the adopted codec. MPEG-2 is no longer compliant with the DCI specification. JPEG 2000 is the only accepted compression format.

• Supported frame rates are:
  • SMPTE (JPEG 2000)
    • 24, 25, 30, 48, 50, and 60 fps @ 2K
    • 24, 25, and 30 fps @ 4K
    • 24 and 48 fps @ 2K stereoscopic
  • MXF Interop (JPEG 2000) – Deprecated
    • 24 and 48 fps @ 2K (MXF Interop can be encoded at 25 frame/s but support is not guaranteed)
    • 24 fps @ 4K
    • 24 fps @ 2K stereoscopic
  • MXF Interop (MPEG-2) – Deprecated
    • 23.976 and 24 fps @ 1920×1080
• Maximum frame sizes are 2048×1080 for 2K DC, and 4096×2160 for 4K DC. Common formats are:
  • SMPTE (JPEG 2000)
    • Flat (1998×1080 or 3996×2160), ~1.85:1 aspect ratio
    • Scope (2048×858 or 4096×1716), ~2.39:1 aspect ratio
    • HDTV (1920×1080 or 3840×2160), 16:9 aspect ratio (although not specifically defined in the DCI specification, this resolution is DCI compliant per section 3.2.1.2).
    • Full (2048×1080 or 4096×2160) (Official name by DCI is Full Container)
  • MXF Interop (MPEG-2) – Deprecated
    • Full Frame (1920×1080)
• 12 bits per pixel precision (36 bits total)
• XYZ colorspace
• Maximum bit rate is 250 Mbit/s (1.3 MBytes per frame at 24 frame/s)

Sound MXF files

Sound contents are stored in reels, too, corresponding to picture reels in number and duration. In case of multilingual features, separate reels are required to convey different languages. Each file contains linear PCM essence.

• Sampling rate is 48,000 or 96,000 samples per second
• Sample precision of 24 bits
• Linear mapping (no companding)
• Up to 12 independent channels.
• WAV container

Asset map file

List of all files included in the DCP, in XML format.

Composition playlist file

Defines the playback order during presentation. The order is saved in XML format in this file; each picture and sound reel is identified by its UUID. In the following example, a reel is composed by picture and sound:

<Reel>
 <Id>urn:uuid:632437bc-73f9-49ca-b687-fdb3f98f430c</Id>
 <AssetList>
  <MainPicture>
   <Id>urn:uuid:46afe8a3-50be-4986-b9c8-34f4ba69572f</Id>
   <EditRate>24 1</EditRate>
   <IntrinsicDuration>340</IntrinsicDuration>
   <EntryPoint>0</EntryPoint>
   <Duration>340</Duration>
   <FrameRate>24 1</FrameRate>
   <ScreenAspectRatio>2048 858</ScreenAspectRatio>
  </MainPicture>
  <MainSound>
   <Id>urn:uuid:1fce0915-f8c7-48a7-b023-36e204a66ed1</Id>
   <EditRate>24 1</EditRate>
   <IntrinsicDuration>340</IntrinsicDuration>
   <EntryPoint>0</EntryPoint>
   <Duration>340</Duration>
  </MainSound>
 </AssetList>
</Reel>

Packing list file

All files in the composition are hashed and their hash is stored here, in XML format. This file is generally used during ingestion in a digital cinema server to verify if data have been corrupted or tampered with in some way. For example, an MXF picture reel is identified by the following <asset> element:

<Asset>
 <Id>urn:uuid:46afe8a3-50be-4986-b9c8-34f4ba69572f</Id>
 <Hash>iqZ3X7TdAjAqniOxT2/hj66VCUU=</Hash>
 <Size>210598692</Size>
 <Type>application/x-smpte-mxf;asdcpKind=Picture</Type>
</Asset>

The hash value is the Base64 encoding of the SHA-1 checksum. It can be calculated with the command

openssl sha1 -binary "FILE_NAME" | openssl base64

Volume index file

A single DCP may be stored in more than one medium (e.g., multiple hard disks). The xml file VOLINDEX is used to identify the volume order in the series.

3D DCP

The DCP format is also used to store stereoscopic (3D) contents. In this case, 48 frames per second are used, with frames alternating for left eye and right eye pictures. Since the maximum bit rate is always 250 Mbit/s, this results in a net 125 Mbit/s for single frame, but the visual quality decrease is generally unnoticeable.

DCP creation

Most film producers and distributors rely on digital cinema encoding facilities to produce and quality control check a digital cinema package before release. Facilities follow strict guidelines set out in the DCI recommendations to ensure compatibility with all digital cinema equipment. For bigger studio release films, the facility will usually create a DCDM (Digital Cinema Distribution Master).

A DCDM is the post-production step prior to a DCP. The frames are in XYZ TIFF format and both sound and picture are not yet wrapped into MXF files. A DCP can be encoded directly from a DCDM. A DCDM is useful for archiving purposes and also facilities can share them for international re-versioning purposes. They can easily be turned into alternative version DCPs for foreign territories. For smaller release films, the facility will usually skip the creation of a DCDM and instead encode directly from the DSM (Digital Source Master) the original film supplied to the encoding facility. A DSM can be supplied in a multitude of formats and colour spaces. For this reason, the encoding facility needs to have extensive knowledge in colour space handling including, on occasion, the use of 3D LUTs to carefully match the look of the finished DCP to a celluloid film print. This can be a highly involved process in which the DCP and the film print are "butterflied" (shown side by side) in a highly calibrated cinema.

Less demanding DCPs are encoded from tape formats such as HDCAM SR. Quality control checks are always performed in calibrated cinemas and carefully checked for errors. QC checks are often attended by colourists, directors, sound mixers and other personnel to check for correct picture and sound reproduction in the finished DCP.

DCP encryption

The AES encryption is applied to all MXF files. The encryption keys are generated and transmitted via a KDM (Key Delivery Message) to the projection site. KDMs are XML files that can be opened only by the destination device. A KDM is associated to each playlist and defines the start and stop times of validity for the projection of that particular feature.

DCP delivery methods

The most common method uses a specialist hard disk (most commonly the CRU DX115) designed specifically for digital cinema servers to ingest from. These hard drives were originally designed for military use but have since been adopted by digital cinema for their hard wearing and reliable characteristics. The hard drives are usually formatted in the Linux EXT2 or EXT3 format. Usually the iNode is set to 128 bits to avoid compatibility issues with some servers. Also, NTFS and FAT32 are occasionally used but they are generally not considered flexible enough since some Linux based digital cinema servers (such as those made by Dolby and Sony) are unable to read these formats. Hard drive units are normally hired from a digital cinema encoding company, sometimes in quantities of thousands. Drives are commonly shipped in protective hard cases. The drives are delivered via express courier to the exhibition site. Other, less common methods adopt a full digital delivery, using either dedicated satellite links or high speed Internet connections.

DCP creation tools

DCP creation tools

Name	GUI	CLI	JPEG 2000	XYZ	MXF	XML	Frame size	3D	Frame rate (frame/s)	Sampling rate (kHz)	Multi-threaded	Input formats	Notes	OS	License
2DCP_GUI	Yes	Yes	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 48	48, 96	Yes	Multiple	Picture scaling	Windows	Freeware
CineCert AS-DCP File Access Library	No	Yes	No	No	Yes	No	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48, 96	Yes	J2K, WAV, XML	Needs separate codec	Windows, Mac OS X, Linux	BSD-like
Doremi CineAsset	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 48	48		Multiple video formats, TIFF, DPX, and others		Windows, Mac OS X	Commercial license
Cinemaslides	No	Yes	Yes	Yes	Yes	Yes	2K, 4K	No	24, 48	48, 96	No	All known image and audio formats	Encryption, KDM generation. Needs separate codec	Linux	GPLv3
DVS Clipster	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 48	48		Multiple formats		Windows	Commercial license
DCP Builder	Yes	Yes	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 48	48, 96	Yes	BMP, TIFF, DPX, PNG, SGI, TGA	No encryption, needs registration	Windows, Mac OS X, Linux	Freeware
DCPC – Digital Cinema Package Creator	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48	Yes	Multiple formats	Needs separate codec	Windows
Prism DCP Encoder	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 48	48	Yes	DPX, CIN, TIFF, PNG, BMP, TGA, JPG	Picture scaling presets	Windows	Commercial license
Inition DCP Pro	Yes	No	Yes	Yes	Yes	Yes	2K	Yes	24	48		Multiple formats	Network encoding of JPEG 2000 files	Windows	Commercial license
DCP Tool	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 48	48	Yes	TIFF, DPX, WAV, AIFF	Two separate tools	Windows	Commercial license
Dietrich	No	Yes	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48, 96		DCDM, DCP, MXF, XML	Encryption, key management, KDM generation, package validation, subtitles	Linux
YADE - DCP encoder	Yes	Yes	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48, 96	Yes	TIFF, PNG, BMP, DPX, J2K, XML, DCP, DCDM, MXF	Encryption; KDM and key management; Interop/SMPTE subtiltes; uses ultra fast, proprietary jpeg2000 codec (jade2k); highly scalable	Windows, Linux	Commercial license
Fraunhofer IIS easyDCP Creator	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	No	24, 25, 30, 48, 50, 60	48	Yes	DPX, TIFF, J2K, JPEG, GIF, PNG, BMP		Windows, Mac OS X	Commercial license
Fraunhofer IIS easyDCP Creator+	Yes	Yes	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48	Yes	DPX, TIFF, J2K, JPEG, GIF, PNG, BMP	Supports KDM and encryption with included easyDCP KDM Generator	Windows, Mac OS X	Commercial license
Magna Mana FinalDCP	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 48	48	Yes	AVI, QuickTime, RED R3D, CineForm, DPC (DPX-C), JPEG2000, MXF	Network rendering engine	Windows, Mac OS X	Commercial license
Extron J2KENC	Yes	No	Yes	Yes	Yes	No	2K	Yes	24	48	No	BMP, DPX, PNG, TGA, TIFF		Windows	Commercial license
opencinematools	Yes	Yes	Yes	No	Yes	Yes	2K, 4K	Yes	24, 48	48	No	TIFF		Windows, Mac OS X, Linux	BSD
OpenCubeDCP	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 48	48		DPX, CIN, TIFF, TGA, BMP, SGI, RAW, RGB, YUV, WAV	Rack mounted unit	Linux	Commercial license
OpenDCP	Yes	Yes	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48 , 96	Yes	TIFF, DPX, CIN	XML file generation with digital signatures	Windows, Mac OSX, Linux	GPL
intoPIX PRISTINE J2K Accelerator	No	Yes	Yes	No	No	No	2K, 4K	Yes	24, 25, 30, 48, 50, 60			Multiple formats	Up to 100 fps in 2K, up to 24 fps in 4K, PCIe board	Windows, Linux	Commercial license
QubeMaster Pro	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48, 96	Yes	Multiple formats DPX, CIN, TIFF, TGA, BMP, AVI, QT, ASF, AUD, WAV, TXT		Windows	Commercial license
Dolby SCC2000	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48, 96		All common D-Cinema master file formats	Standalone unit, render farm	Linux	Commercial license
CineCert Wailua DCP Mastering System	No	Yes	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48, 96	Yes	TIF, DPX, J2K, MXF, WAV, XML	DCP testing (individual assets and entire packages), Support for creating partial ("supplemental") DCPs, Encryption, KDM creation, Extensive Python API; Kii add-on module required for JP2K compression, colorspace conversion, and pixel array resizing	Mac OS X, Linux	Commercial License
QuVIS Wraptor	Yes	No	Yes	Yes	Yes	Yes	2K	No	24	48		Multiple formats	Plugin for Compressor in Final Cut Studio. Works well with all versions of FCP and Compressor.	Mac OS X	Commercial license
QubeMaster Xpress	Yes	No	Yes	Yes	Yes	Yes	2K	No	24	48	Yes	Multiple formats		Windows	Commercial license
QubeMaster Xport	Yes	No	Yes	Yes	Yes	Yes	2K, 4K	Yes	24, 25, 30, 48, 50, 60	48	Yes	Multiple formats	Plugin for Compressor in Final Cut Studio.	Mac OS X	Commercial license

External links

• Digital Cinema Initiatives
• Digital Cinema Naming Convention