Preservation

Motion Picture Film Maximum Capture - 4K [MPD-P1]

Record Type Digital Moving Images from Film-based Source Material
Expected Use Preservation Master
Product Name Motion Picture Film Maximum Capture - 4K [MPD-P1]
Product Purpose

The purpose of this product is to mitigate risk for loss of information. This file is at an appropriate information capture level to substitute for the original record if the original record copy is no longer viable.

Nature of Source Material

All 35mm film elements (B&W or color) and 16mm Kodachrome elements with or without optical sound

  • in an advanced stage of deterioration as demonstrated by a determination of “High” or above on the At Risk Assessment Guide and
  • where a preservation film element cannot be created by photochemical means and
  • all possible significant visual picture quality and auditory information is carried forward.
File Properties Data Format

The capture process may result in two separate files linked by metadata.

Image Data

  • DPX (Digital Picture Exchange) as defined by SMPTE 268M-1994
  • Uncompressed
  • Version 1

Audio Data (if present)

  • Broadcast WAV (.wav) as defined by The European Broadcasting Union in document Tech 3285
  • Uncompressed
  • Version: 1
Capture Information

Image Data

  • Bit Depth: 10 Bit
  • Resolution: 4K (4096x3112)
  • Color space: 4:4:4
  • Color model: RGB
  • Log
  • Byte order: Big endian

Typical file size: ~ 68 GB/minute or 4 TB/hour

Audio Data (if present):

  • Encoded to Linear Pulse Code Modulation (LPCM)
  • Sampling frequency: 96 kHz
  • Bit depth: 24
  • Sound field: mono or dual mono

Typical file size: Mono: ~ 17.28 MB/minute or 1 GB/hour; Stereo: 134.5 MB/minute or 2 GB/hour

Possible File Derivatives

4K DPX preservation master files can make both HD DPX and SD MPEG-2 50Mbps reproduction master files.

Other Information
  • If the source element contains a composite soundtrack, the soundtrack image will be contained within the DPX file sequence.
  • Due to its very large file size, it is not accessed directly by researchers and only sent to vendors under certain circumstances.
  • The integrity of the source aspect ratio will be retained.
  • This file will not be altered in any capacity except for one-light color timing to be employed at the initial capture stage.
Quality Control Item Level Evaluation: Automated Quality Analysis

Using automated batch-processing software tools, test plans are developed for each format and/or each appropriate project. The test plan allows for some characteristics to be evaluated on an actionable basis (warning, fail or pass depending on the defined parameters). Others are logged for internal use but are not actionable as a warning, pass or fail. Aim points for these benchmarks are evaluated against NARA's product specifications as well as NARA defined aim points which may change depending on specific project goals. The following represents a typlical quality test plan for selected technical characteristics for DPX products. Test plans are limited by software capabilities. NARA is continuing to improve and refine its QC processes.

Terms used in the QC protocols are defined in the Glossary of Terms.

Technical Characteristic Warning/Pass/Fail or Logged Data
  • Frame Rate
  • Resolution
  • Resolution Change
  • RGB Color Gamut
Warning/Pass/Fail
  • Average Bitrate (Mbps)
  • Duration
Logged data
Rationale

For digital products created from film-based source material, the specifications are dictated by the source material’s original characteristics including format and condition. Materials in advanced stages of deterioration as measured on the At Risk Assessment Guide are scanned to include all the available visual information within a DPX sequence including the optical soundtrack if available. When reproduction copies are needed, a second file without the soundtrack image may be generated through reprocessing the over-scanned image to mask the soundtrack. One-light color timing will be employed as appropriate during the initial capture process, but otherwise, the preservation files are unaltered. Reproduction and distribution files may have additional image improvements such as the use of restoration tools including dust and scratch removal as needed and scene-by-scene color correction.

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