Motion Picture Film Median - Soundtrack Audio Data [MPD-R6]

Record Type Digital Moving Images from Film-based Source Material
Expected Use Reproduction Master
Product Name Motion Picture Film Median - Soundtrack Audio Data [MPD-R6]
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 ONT, DNT, MPT and MAG soundtrack elements

  • in stable condition as demonstrated by a determination of “Medium” or below on the At Risk Assessment Guide and
  • of high content value and/or of high cultural/historical significance and
  • all possible significant visual picture quality and auditory information is carried forward.
File Properties Data Format
  • Broadcast WAV (.wav) as defined by The European Broadcasting Union in document Tech 3285
  • Uncompressed
  • Version: 1
Capture Information
  • Encoded to Linear Pulse Code Modulation (LPCM)
  • Sampling frequency: 48 or 96 kHz
  • Bit depth: 24
  • Sound field: mono

Typical file size: Mono: at least 16 MB/minute or 1 GB/hour

Possible File Derivatives

This product can be use to make distribution files.

Quality Control Quality Control for Digital Audio Files

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 the quality test plan technical characteristics for WAV and MP3 products.

Embedded metadata compliance: NARA follows the FADGI Embedded Metadata in Broadcast WAVE File Guidelines. NARA does not embed metadata into MP3 files.
Technical metadata: NARA is finalizing a technical metadata schema for audio files based on the same structure as its reVTMD schema for video technical metadata.

Item Level Evaluation: Automated Quality Analysis

Fixity: NARA is evaluating workflows to create and validate checksums for each digital file.

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

Technical Characteristic Warning/Pass/Fail or Logged Data
  • Sampling Frequency (Hz)
  • Audio Channels (Number)
  • Bits per sample (Number)
  • Duration
  • Average audio level
  • Peak levels
Logged data

This product creates a separate WAV file to capture audio data. This will be synched to the image data in the HD DPX reproduction master.

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The U.S. National Archives and Records Administration
1-86-NARA-NARA or 1-866-272-6272