IMF Packages

An IMF Package (IMP) is a directory. Everything in it is described by the ASSETMAP.

my-title.imp/
├── ASSETMAP.xml
├── PKL_<uuid>.xml
├── CPL_<uuid>.xml        # one or more
└── <uuid>.mxf            # track files (video, audio, subs, etc.)

ASSETMAP

The entry point. Lists every file in the package with its UUID and relative path. imferno reads this first to build the file index.

<AssetMap xmlns="http://www.smpte-ra.org/schemas/429-9/2007/AM">
  <Id>urn:uuid:...</Id>
  <AssetList>
    <Asset>
      <Id>urn:uuid:...</Id>
      <ChunkList>
        <Chunk>
          <Path>CPL_abc123.xml</Path>
        </Chunk>
      </ChunkList>
    </Asset>
    ...
  </AssetList>
</AssetMap>

PKL — Packing List

Lists every file with its size and SHA-1 hash. Used for integrity verification. A package can have multiple PKLs (one per volume in a multi-volume delivery).

CPL — Composition Playlist

The timeline. A CPL describes one version of the title — a specific language, territory, or rating cut. It references track files by UUID and defines how they are assembled into segments and sequences.

Segments and sequences

A CPL contains one or more segments (acts or reels). Each segment contains sequences — parallel tracks:

• MainImageSequence — video
• MainAudioSequence — audio channels
• SubtitlesSequence — subtitles
• ForcedNarrativeSequence — forced narrative (burned-in subtitles)
• HearingImpairedCaptionsSequence — captions
• IABSequence — immersive audio (Dolby Atmos)

Each sequence contains resources — references to ranges within MXF track files, with entry point, source duration, and edit rate.

Supplemental packages

A title can have multiple CPLs sharing the same essence. A supplemental CPL adds a new version (say, a Dutch dub) without duplicating the video MXF — it just points to the same file UUID.

imferno tracks supplemental relationships via the isSupplemental flag on CplReport.

Application profiles

CPLs declare which Application profile they conform to:

Profile	Description
App#2	Standard HD/UHD
App#2E	UHD with HDR (Dolby Vision, HDR10)
App#2Extended	Extended color / dynamic range
App#5	IMAX

imferno detects the profile from the ApplicationIdentification element in the CPL.