wkflw_metadata_teaser

Metadata

Data from set to post

What is metadata?

Metadata is a set of descriptive data that gives information about other data. Time code, for example, is a typical type of metadata. ARRI cameras deliver a wide range of automatic and human-readable metadata that is intended to make production and postproduction tasks easier.

Information about the exposure index, gamma, and white balance in a shot may be important during camera testing, when dailies are created, or in a color grading session. Reel number, project fps, date, and time are crucial when combining image and sound. Dynamic information from our ARRI Lens Data System and the roll and tilt sensors can be useful for visual effects work.

Dynamic and static metadata
Dynamic metdata changes within the shot, it is updated instantly but usually saved "per frame". Static metadata on the other hand does not change within the shot, it is delivered "per shot".

ARRI Metadata

An ARRI camera automatically collects metadata when shooting. The metadata is stored in the header of a recorded MXF/ARRIRAW file, ARRIRAW single frames, Apple MXF/ProRes clip, Apple QuickTime file, and in the Serial Digital Interface (SDI) stream.

The data is also stored in a separate Avid Log Exchange ALE file, which keeps track of all clips that were recorded on one capture device. Metadata (static and dynamic) can be extracted from the file header by using the ARRI Reference Tool or  ARRI Meta Extract (legacy).

Ressources
For reading & writing our metadata we offer the ARRI MXF Library and ARRI Image SDK. Information is available through our ARRI Partner Program, free of charge.

wkflw_ALEXA_35_metadata_json

"Officially Spec'ed" Metadata File Header

For all clips recorded by ALEXA 35 and ALEXA 265 or later, we are writing the file header metadata according to SMPTE specifications:

Our RDDs (Registered Disclosure Documents) can be downloaded from SMPTE free of charge:

  • RDD 54:2022 - SMPTE RDD - Material Exchange Format — Mapping ARRIRAW Bitstreams into the MXF Generic Container
  • RDD 55:2022 - SMPTE RDD - Material Exchange Format — Carriage of ARRI Camera System Metadata

Enhancements to the metadata described in RDD55:2022

Metadata in SDI

We embed different types of metadata into the SDI. Metadata refers to all data besides image content. This data is located in the HANC and VANC space of the SDI signal.


More information in our white papers below:

Metadata via the Camera Access Protocol (CAP)

CAP is used to control and monitor ARRI cameras via a network connection. The protocol incorporates functions to perform color grading, query, set values like exposure index, start/stop recording, and many more. It is currently available for ALEXA 35, ALEXA Mini LF, ALEXA LF, ALEXA 65, ALEXA SXT, ALEXA Mini, and AMIRA cameras.

Functional Overview of CAP
Metadata

  • Read clip list (also partial; including file name, UUID, project rate, start TC, clip duration)
  • New variables for last recording medium & clip index allows for staying up-to-date with clip metadata changes
  • Read ALE file (also partial)
  • Read static & dynamic lens metadata
  • Lens model, serial number, focus, iris, zoom
  • Read & set production metadata: scene, take, production, director, etc.
  • Camera control & miscellaneous

Playback control

  • Enter (with clip index), exit, start, stop, prev/next clip, playback speed, shuttle
  • Set & read TC and TC options: offset, run mode, init mode, count mode
  • Set & read project rate
  • Install look file from look library
  • Access to camera alerts & events
  • SDI frame grabs in JPG format
  • Read & set system date/time


Ressources
Information on the Camera Access Protocol is available through our ARRI Partner Program, free of charge.

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