February 23, 2018

DCP 101: A Digital Cinema Package Primer

by: Matt Small
Post Production Lead

Congratulations – your film has been accepted to a festival! As part of the announcement, the festival’s technical team is asking for your DCP to be delivered prior to the event.  If this is new territory, you might have googled it and quickly realized that it’s a lot more complicated than an average delivery format. If it’s something you’ve done before, you know that in order to showcase your film in its best possible form, the DCP needs to be tailored for the unique needs of the venue. Let’s dig a little deeper into DCPs and what they entail.

 

What is a Digital Cinema Package (DCP)?

The short answer is that a DCP is the standard format for digital projectors used in theaters. It’s a container for everything your venue’s projector needs in order to read, interpret, and play back your film. The festival should provide you with format specifications, as there are lots of options. You’ll need this information in order to build your package properly.

  • Dropping your file into Adobe Media Encoder is a risky shortcut that can result in a file that is stretched or squished, among other things.
  • In addition, traditional playback programs like Quicktime, VLC and Windows Media Player will not play this niche format. Some third-party apps are available online, but unless you happen to have a theater with the right projector handy, you’re not going to get an accurate test. Testing your end result is the only way to guarantee that you’re supplying a high-grade product suitable for a festival crowd. 

 

 

Files in a DCP

The point to belabor: your DCP needs to meet the unique requirements of the festival and venue in order to ensure a top-quality viewing experience. The “package” in Digital Cinema Package is a collection of files that include your video and audio (as MXF files) and several other metadata files (as XML files) that tell the projector where things are and how and when to play them. You won’t have to make any of these by hand—but it’s good to be familiar with each so you can recognize them when you see them.

  • Video File (.MXF)
  • Audio File (.MXF)
  • Asset Map (.XML)
    • The asset map is a list of files provided in your package
  • Composition Playlist (.XML)
    • The composition playlist provides the reel playback order instructions
  • Package Key List (.XML)
    • Used in ingestion to verify data
  • Volume Index File (.XML)
    • Used if files are being provided on multiple drives

 

Creating the Video File

Below are three types of compression, each with its own specifics, that are likely to be called for within the festival requirements. Some considerations that your DCP creation plan should account for:

  • Consider the native format, frame rate, and frame size of your film. Know where you’re starting and where you have to go to fit your content into the specification.
  • Will your screening venue use a 2k or 4k projector? We’ll get into this a bit more in the next section.
  • Video file size is very large—in the hundreds of GB’s, depending on length.
  • The DCP specification compresses your file to a maximum bit rate of 250 Mbit/s. You want to get as close as possible to this limit to maximize quality.

 

COMPRESSION

FRAME SIZE

FRAME RATE

SMPTE JPEG 2000

2K

24*, 25, 30*, 48 (3D), 60

4K

24, 25, 30

MXF JPEG 2000

2K, 4K

24

MXF MPEG-2

HD

23.98 or 24

*In keeping with its “cinema” heritage, the DCP format requires true 24 and 30 frames per second material, not the 23.98 or 29.97 drop-frame rate of digital video.

Frame Size and Aspect Ratio considerations

In the DCP workflow you’ll notice a few holdovers from the era of analog film projection. One of these examples can be seen in DCP frame dimension requirements. Film-based theater projectors had two lenses – flat and scope, which would be rotated in or out based on the aspect ratio of the film. The format is still divided into these two specifications, but the information is now embedded into the file and the projector automatically makes the switch.

  • “Flat” is better for 16:9 material
  • “Scope” is 2.39:1 and better for material closer to 2.35:1
  • Pro Tip: Save yourself a headache and fit your movie into one of the specific dimensions below rather than making the conversion during the DCP creation. This might result in pillarboxes or letterboxes to maintain your original aspect ratio. Then you’ll know before you get to the complex DCP creation that you have the right frame size.

 

FRAME SIZE

FULL

FLAT DIMENSIONS

SCOPE DIMENSIONS

HD

1920 x 1080

1920 x 1080

--

2K

2048 x 1080

1998 x 1080

2048 x 858

4K

4096 x 2160

3996 x 2160

4096 x 1716

 

 

Creating the audio file

Some basic considerations / expectations to ensure that your audio quality is on point:

  • DCP offers 16 audio channels, so it can support up to 11.1 immersive audio surround mixes.

Stick with 24-bit audio at a sample rate of either 48 or 96 kHz.

 

Other considerations:

Is the venue using a 2K projector or 4K projector?

If the festival doesn’t specify the playback equipment they’re using, this is an important question to ask.

  • In our tests here at Westworks Studios, a newer 2K projector was able to accept and auto-down-convert a 4K file; but older projectors might not be as successful.
  • At the same time, a 4K projector will up-convert and play 2K files, but potentially at the cost of quality.
  • Our recommendation: deliver your files in both 2K and 4K. It’s a smart contingency plan that will leave your film prepared for any changes with the venue’s capabilities.

How will you play back your DCP for testing?

The short answer: it’s really hard. Unless you have access to either the venue itself, or a comparable projector, you’ll need a software solution that enables you to emulate a theater-quality playback experience. That can be a costly proposition.

In fact, the ability to test your festival-ready package is one of the biggest advantages to using a cost-effective professional service to compile and package your entire DCP. WestWorks utilizes industry-standard hardware and software to create and test DCP files.

When quality assurance is baked into the entire process, your presentation is well on its way to a best-possible conclusion.

 

What are your security needs?

The DCP format offers encryption capabilities, which is great for big studios, or whenever there’s a need to keep pre-released films secure. Encryption adds a layer of complication, however, and it’s not something we recommend unless it’s being performed as a professional service.

Whether you choose to compile your DCP yourself or engage a professional service, you want your project to look and sounds its best for a discerning festival audience. Westworks Studios has over two decades of experience in video production, and employs the right tools and talent to elevate the quality of your presentation. We’re happy to consult with you about your specific needs, and can tailor your DCP according to the requirements of any festival.