Preservation

Video Reproduction Master - SD [VID-R1]

Record Type: Digital Moving Images from Video Source Material

Expected Use: Reproduction Master

Product Name: Video Reproduction Master - SD [VID-R1]

Product Purpose: The purpose of this product is to respond to reference and reproduction requests.

Nature of Source Material: Any digital master video file not at risk due to deterioration or obsolescence.

Possible File Derivatives: This product can be used to create distribution files of equal or lesser quality.

Other Information: This product could also be used as a broadcast or production quality deliverable.

File Properties

Container Format

Container:

File Specifications

Target Total Bitrate: 50.8 Mbps

Timecode: Source LTC/VITC

Video data

  • Frame size: 720x480
  • Video codec: MPEG-2 MainConcept
  • Video bitrate: 50Mbps
  • Video mode: CBR
  • Video frame rate: 29.97 fps
  • Chroma subsampling: 4:2:2
  • 4:2:2 Profile, Main Level
  • Closed GOP, I-frame only
  • Lower field first
  • Interlaced 
  • Single-pass encoding

Audio data

  • Audio channels: 2 (stereo L R)
  • Audio bitrate: 224 Kbps
  • Audio mode: CBR
  • Audio codec: MPEG Layer 2
  • Audio sample rate: 48 kHz
  • Bit depth: 16 bit

Typical file size: ~ 360 MB/minute or 21.6 GB/hour

Quality Control

Quality Assurance and Quality Control for Reproduction Master Video Products

The Audio-Video Lab relies on visual and auditory quality control (QC) and spot checks to confirm completeness and technical characteristics of the files.

Metadata

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, and item number.

Rationale

For digital products created from video source material, the specifications are dictated to some extent by hardware and software capabilities.

Reproduction masters are at a high enough quality that they may be used in a production context.  Distribution copies are at a low enough bitrate that they are able to be easily streamed or downloaded via an internet connection. 

The National Archives and Records Administration's (NARA’s) options for reproduction masters are in line with peer institutions.

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