Motion Picture Film Maximum Capture - Soundtrack Audio Data WAV [MPD-P6]

Record Type: Digital Output from Motion Picture Film Source

Expected Use: Preservation Master

Product Name: Motion Picture Film Maximum Capture - Soundtrack Audio Data WAV [MPD-P6]

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 (Original Negative Track), DNT (Duplicate Negative Track), MPT (Master Positive Track), and MAG (Magnetic Track) soundtrack elements, as well as composite elements:

  • in an advanced stage of deterioration as demonstrated by a determination of “High” or above on the At Risk Assessment Guide and
  • where it is not practical to create a preservation film element by photochemical means and
  • all possible significant auditory information is carried forward.

Possible File Derivatives: Preservation master WAV files can make reproduction master files and distribution copies. The audio data in this product may be synced with associated DPX (Digital Moving-Picture Exchange) image data to create derivatives.

File Properties

Container Format
File Specifications
  • Encoded to Linear Pulse Code Modulation (LPCM)
  • Sampling frequency: 96 kHz
  • Bit depth: 24 bit
  • Sound field: mono (for multi-channel source, each channel is captured as a separate mono file)


Typical file size: ~17.28 MB/minute or ~1 GB/hour

Quality Control

Quality Control for Digital Audio Files

The National Archives and Records Administration (NARA) uses a commercially available, automated batch processing software tool to evaluate specific quality metrics. Below is a description of our current processes for WAV products.

Equipment/System Evaluation

NARA implements scheduled service and calibration protocols according to manufacturer recommendations as well as on an "as needed" basis.


The filename contains metadata that associates the file with external sources of descriptive and technical metadata. Each filename is a unique identifier composed of the item’s record group, series, item number, and reel number, with the source element type appended as a suffix for WAV files (ex. 255-hq-199-r2_p.wav).

Embedded metadata compliance: NARA follows the Federal Agencies Digital Guidelines Initiative  (FADGI) Embedded Metadata in Broadcast WAVE File Guidelines

Technical metadata: NARA uses BWF MetaEdit to embed basic technical metadata, including Coding History.

Item Level Evaluation: Automated Quality Analysis

Test plans are developed on a format/workflow basis in our automated quality control (QC) tool. 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. The following represents the quality test plan technical characteristics for preservation WAV products captured from motion picture film.

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


The NARA Motion Picture Preservation Lab uses checksum verification for file transfers and for files in long-term storage.


This digital preservation master product is in line with published guidelines and best practices including the International Association of Sound and Audiovisual Archives (IASA) TC-04: Guidelines for the Production and Preservation of Digital Audio Objects and the Association for Recorded Sound Collections (ARSC) Guide to Audio Preservation.

For digital products created from film-based source material, the specifications are dictated by the source material’s original characteristics including format and condition. A separate WAV file is created for all at risk stand alone sound elements as identified on the At Risk Assessment Guide.