What Is a DCP?
If your film is going to play in a cinema — any cinema, anywhere in the world — it needs to be in a very specific format. That format is the DCP: Digital Cinema Package.
It replaced 35mm film as the universal standard for cinema exhibition. Since around 2012 it has been the only format that professional digital cinema projectors are designed to play. Whether your film is a major studio release or a short film at a local festival, the cinema server expects a DCP.
What Is Inside a DCP?
A DCP is not a single file. It is a folder of files — typically containing:
- MXF files — these carry the picture and audio data, encoded in JPEG2000 (for picture) and PCM (for audio). A feature film DCP might be 100–300 gigabytes.
- XML files — the CPL (Composition Playlist) tells the cinema server what to play and at what specification. The PKL (Packing List) lists every file and its checksum. The ASSETMAP tells the server where to find each file.
- Additional tracks — subtitle files, access material tracks, and encrypted key files if present.
The whole package is governed by specifications set by the DCI (Digital Cinema Initiatives) and standardised by SMPTE, the Society of Motion Picture and Television Engineers.
How Is a DCP Different From a Normal Video File?
Normal video files use codecs like H.264 or ProRes. DCPs use JPEG2000 — a wavelet-based compression format chosen specifically for cinema. The maximum picture bitrate in a DCP is 250 megabits per second — far higher than any consumer or broadcast video format.
Video files typically use Rec.709 colour space. DCPs use XYZ colour space — a larger colour container designed for cinema projectors. Converting your video into XYZ colour space correctly is one of the key technical steps in making a DCP.
The Two DCP Container Sizes
DCPs come in two container sizes: Flat (1.85:1) at 1998×1080 pixels at 2K, and Scope (2.39:1) at 2048×858 pixels at 2K. These are fixed. Whatever aspect ratio your film is, it goes into one of these two containers.
What Frame Rates Does a DCP Support?
The DCP specification supports only whole-number frame rates: 24, 25, 30, 48, 50, and 60 frames per second. The fractional frame rates common in video workflows — 23.976 and 29.97 — do not exist in cinema. If your film was edited at 23.976, it needs to be conformed to 24fps before a DCP can be made.
Checksums
Every file in a DCP has a mathematical fingerprint called a checksum. When a cinema server ingests a DCP, it verifies every file against these checksums. One corrupted byte will cause the server to refuse ingest entirely. This is why verification matters — and why we verify every DCP before it leaves us.
Worth knowing: A DCP that plays on your computer is not the same as a DCP that has been verified against a cinema server. We test every DCP we make on actual server hardware before delivery.
2K or 4K?
2K is the dominant format and plays correctly on the vast majority of cinema screens worldwide. 4K plays beautifully on venues with native 4K projectors — but because both formats share the same maximum bitrate of 250mbps, a well-encoded 2K DCP often outperforms the 2K substream extracted from a 4K DCP on a 2K projector. For clients with UHD source material who want to cover all bases, we offer a combined 4K + 2K package from a single mastering session.