Blog post

IMF Requirements

October 18, 2017markok

Interoperable Master Format (IMF)

IMF Image Format

IMF is a single, interchangeable master file format based on JPEG2000 compression to minimize storage requirement, allowing flexible versioning of the content. A single IMF package (IMP) may contain a variety of versions of the same content: different language, aspect ratios or playlists. It is loosly based on the DCP concept.

Supports the following IMP features:
  • HD, QHD and 4K
  • Application 2, Application 2 Extended, Application 2+ (revised) and Application 4
  • YUV and RGB
  • Supporting wide range of framerates for packages: • 23.976, 24, 25, 29.97, 30,48, 50, 59.94, 60• 10, 12 and 16bit
  • Lossy and Lossless profiles • available deliverables meet the requirements for the following IMF specifications: NETFLIX, FOX, SONY, WARNER.
  • HDR masters, such as Dolby Vision mezzanine files, HDR-10 HEVC or PQ Rec2020 IMF packages.IMF Audio Format

IMF Audio Format

The audio files shall have the following attributes:
  • Files must be in reels matching the image file reels
  • The sampling clock rate shall be exactly 48,000.000 Hz or 48 KHz at exactly image Frame Rate
  • Reference level shall be -20dbfs
  • Mix needs to be properly naming
  • Audio files shall be wrapped depending the IMF application
Audio files shall be wrapped for 5.1 sound with the following channel assignments:
  • Channel 1—Left
  • Channel 2—Right
  • Channel 3—Center
  • Channel 4—LFE
  • Channel 5—Left Surround
  • Channel 6—Right Surround
If two (2) channels of sound (Stereo—LtRt) are required, a separate CPL shall be used within the same DCP.


Finalize Version File Packages (Supplementals)

Version File (aka Supplemental) packages are IMPs with such playlists (CPLs) that contain assets from other packages. Original Version IMPs on the other hand are self-contained and have all assets inside the IMP.

Version File (VF) packages are supplementing other IMF IMPs. A VF is defining a composition that uses assets from the package as well as assets from other packages, typically an Original Version. Thus, the VF package can be used to fix or alter another package without the need of media duplication. VF packages are most often used to define localised versions of titles with potentially parts of the video or the complete audio replaced, subtitles added.


In case the source is compatible for transwrapping no J2K encoding will be executed, only the source will be rewrapped into a new MXF container.

More information on IMF can be found at the SMPTE website, SMPTE Standards Development Update: IMF.

Leave a comment

Your email address will not be published. Required fields are marked *

Prev Post Next Post