Motion Picture Film Reproduction Master Derivative - HD MP4 [MPD-R3]
Record Type: Digital Output from Motion Picture Film Source
Expected Use: Reproduction Master
Product Name: Motion Picture Film Reproduction Master Derivative - HD MP4 [MPD-R3]
Product Purpose: The purpose of this product is to respond to reference and reproduction requests. It has added NARA identification slates and may have additional overall digital color or density adjustments applied, as well as adjustments for clarity of the audio. The file acts as a reference/distribution master for further compressed derivatives, which are served to researchers.
Nature of Source Material: This product is created from HD AVI or other reproduction master files.
Possible File Derivatives: This product is used to make some types of distribution files.
Other Information: This file contains added NARA identification slates and may have additional overall digital color or density adjustments applied, as well as adjustments for clarity of the audio. It is used as a source for all file derivatives that require the presence of a NARA slate.
File Properties
| Container Format |
|---|
|
MP4 File Format (MPEG-4 Part 14) |
| File Specifications |
|
Target Total Bitrate: ~50.4Mbps
Video data
Audio data
Typical file size: ~378MB/minute or ~22.7GB/hour |
Quality Control
Quality Assurance and Quality Control for Distribution Master MP4 files
NARA uses a commercially available, automated batch processing software tool to evaluate specific quality metrics for files created directly from film captures (see MPD-R2). The MP4 derivative described here is created from an HD AVI file following NARA's Film Reference SOP. We rely on visual QC and spot checks to confirm completeness and accuracy of slates, as well as technical characteristics of the files. If an MP4 does not meet specified requirements, a new file is created from the HD AVI reproduction master.
Metadata
The MP4 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 (ex. 255-hq-199-r2.mp4).
Rationale
This 50Mbps HD MP4 serves as a distribution master file. While the HD AVI reproduction master is saved as it is captured, this MP4 has added slates with identifying information appended, and often has color and audio adjustments applied. Because of its high bitrate, it may be used to transcode MP4 derivatives for almost all NARA purposes. Any HD derivatives that require lower levels of compression must be made from the HD AVI reproduction master file.