Motion Picture Film Restoration Master DPX [MPD-R8]
Record Type: Digital Output from Motion Picture Film Source
Expected Use: Reproduction Master
Product Name: Motion Picture Film Restoration Master DPX [MPD-R8]
Product Purpose: The purpose of this product is to serve as a master DPX (Digital Picture Exchange) file sequence for digital film restorations performed by the Motion Picture Preservation Lab.
Nature of Source Material: Digital restorations are derivatives from 4K or 2K DPX scans. In cases where the motion picture film source material is at high risk, the restoration master files will be saved in addition to the DPX preservation master files. If the motion picture film source material is in stable condition, only the restoration master files will be retained.
Possible File Derivatives: 4K DPX restoration master files can make 4K ProRes 4444 MOV (QuickTime File Format) and HD (High Definition) AVI (Audio Video Interleaved) reproduction master files, and 4K or 2K DCP (Digital Cinema Package) distribution copies. 2K DPX restoration master files can make HD AVI reproduction master files and 2K DCP distribution copies.
Other Information:
- If the source element contains a composite soundtrack, the soundtrack image will be contained within a preservation master DPX file sequence. The soundtrack will be cropped out in the restoration master so the film may be projected with its intended appearance.
- 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.
- The restoration master undergoes color correction and dust/scratch removal.
- Adjustments to improve the clarity of the associated audio WAV (Waveform Audio File Format) file are also performed, and the restored WAV file is stored with the restored DPX sequence.
File Properties
| Container Format |
|---|
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There may be two separate associated files linked by metadata. Image Data
Audio Data (if present) |
| File Specifications |
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Image Data
Audio Data (if present):
Typical 4K image file sequence size: ~102.7 GB/minute or ~6 TB/hour (16 bit) Typical 2K image file sequence size: ~25.7 GB/minute or ~1.5 TB/hour (16 bit) |
Quality Control
Item Level Evaluation: Manual Quality Analysis
DPX technical metadata may be examined and validated using software like the Federal Agencies Digital Guidelines Initiative (FADGI)-developed embARC tool. Visual quality control (QC) may be performed using DPX editing/playback software and a professional monitor. In order to perform automated aspects of visual QC, the DPX sequence must first be transcoded to an uncompressed or other high-quality video file. Test plans are limited by software capabilities. The National Archives and Records Administration (NARA) is continuing to improve and refine its QC processes.
Metadata
NARA saves DPX sequences in folders named to associate the files with external sources of descriptive and technical metadata. The folder name is a unique identifier composed of the item’s record group, series, item number, and reel number (ex. 255-HQ-199-R2). NARA uses the BagIt file packaging specification to generate manifests of the files in a DPX sequence, as well as checksums for each individual file.
The following technical aspects of the DPX sequence and files are evaluated during metadata QC:
- Resolution (4096x3112, 2048x1556)
- Color Model (RGB)
- Bit Depth (16 bit)
- Endianness (Big endian)
- Total number of files (match against sequential numbers in file names to make sure no frames were lost)
Filename
Restoration masters and all of their derivatives must have the word “RESTORATION” appended to the file and/or folder name to help distinguish them from unrestored files created through standard digital reproduction workflows. Any slates added should also note that the file is a restoration.
Fixity
The NARA Motion Picture Preservation Lab uses checksum verification for file transfers and for files in long-term storage.
Rationale
Restored versions of NARA films may be required for special events or projects. Restorations are intended to approximate the appearance of the film at the time it was first created and exhibited. In addition to scene-by-scene color timing, adjustments may be made to improve clarity or remove scratches and other imperfections. Adjustments may be automated or manual. The goal is to improve the image without overcorrecting. Additionally, filters may be applied to the audio to improve clarity. Restored versions of a film are maintained separately from raw scans and are identified as restorations in file names, slates, and metadata.