DCP-Ingestion

What is a DCP?

A DCP — short for Digital Cinema Package — is the industry-standard format for distributing and projecting movies in modern theaters. Think of it as the “film reel” of the digital era, except instead of a physical strip of celluloid, it’s a carefully packaged set of digital files with strict formatting requirements. Read on to learn more about DCPs and the process OIF staff follows to ensure proper playback at a commercial theater.

1. What a DCP Is

  • Purpose: To ensure your film plays correctly on professional cinema projectors anywhere in the world.
  • Standard: Follows the Digital Cinema Initiatives (DCI) specification — a set of rules developed by the major studios to guarantee consistent image, sound, and security.
  • Content:
    • Video encoded in JPEG 2000 format (extremely high quality, high bit rate).
    • Audio in uncompressed 24-bit PCM WAV (usually 48 kHz or 96 kHz).
    • Optional subtitles or closed captions in XML format.
  • Structure: Stored as a set of separate folders and files (for OIF, usually 6 or 7 separate files), not one big movie file.

2. The File Structure

A DCP is usually delivered on an EXT2/EXT3 formatted drive (Linux file system) with:

  1. MXF files – contain the actual image and audio tracks.
    • picture.mxf → JPEG 2000 compressed video.
    • sound.mxf → multichannel audio.
  2. XML metadata files – describe how to play the content.
    • CPL (Composition Playlist) – tells the projector the sequence of audio, video, subtitles.
    • PKL (Packing List) – lists every file in the package with checksums.
    • ASSETMAP & VOLINDEX – help the playback server locate and verify files.
  3. Subtitle XML – if your DCP includes subs.

3. Current OIF Export Structure

  • Resolution:
    • 2K: 1998×1080 (Flat 1.85:1)
  • Frame Rates: 24 fps is the standard
  • Aspect Ratio: Square Pixel (1.0)
  • Bit Depth: 12-bit for video.
  • Codec: Jpeg 2000
  • Audio: Stereo (5.1 is preferred, but since we need the lowest common denominator for all films to play well, we export in Stereo).
  • Time required to export: This depends greatly on the total running times and film formats provided. After assembly, it usually takes many hours, and sometimes days to export the DCPs in a ready state for an OIF screening.

4. Ingesting in a Theater

Theater projection systems have two main components:

  • DCP Server (Media Block) — stores and decodes the files.
  • Digital Projector — displays the image.

Ingest process:

  1. For OIF, we prepare all DCPs according to the above specs for the theater and deliver it on a portable drive, about a week prior to the screening (so we have a chance to fix anything that may not work properly).
  2. The projectionist connects the external drive.
  3. The server ingests (copies) the files into its internal storage.
  4. If the DCP is encrypted, a KDM (Key Delivery Message) is needed — this is a small file from the distributor that unlocks the DCP for playback on that exact server for a specific date range. OIF does not normally encrypt the DCPs.
  5. The server verifies file integrity and metadata.
  6. Once ingested and unlocked, the DCP appears in the playlist for scheduling and playback.
  7. The films and other video assets are checked by OIF staff and/or theater staff for issues in sound or video.
  8. Should there be any issues during the playback sessions, OIF will aks the filmmaker whose film has an issue for a fix and rebuild the DCPs with the corrected films. Time is of the essence at this junction.

DCP-Ingestion