Preservation

Quality Assurance and Quality Control for MPEG-2 Format Products Created on Robotic SAMMA System

NARA uses a commercially available, automated batch processing software tool to evaluate specific quality metrics. Below is a outline of our current processes for HD MPEG-2 formatted products. The exact aim point values are still in the testing phase. Once these values are confirmed, they will be added to this site. We continue to adjust our benchmarks and workflows as needed.

Color Bar Alignment
Color bar alignment is part of the manual video digitization workflow. Video levels are adjusted to original color bars on the source material when possible. When original color bars are not present on the source material, video levels are adjusted to the original content; setup and video level are the primary adjustments. Metadata is embedded into the video file indicating whether the source tape was adjusted to original color bars or the original content. The automated SAMMA workflow does not include color bar adjustment for individual tapes.

Metadata
Embedded metadata compliance: NARA is working with FADGI to develop embedded metadata guidelines for reformatted video. They will be added to this site when complete.
Technical metadata: NARA uses its reVTMD schema for video technical metadata.

Customer Level Evaluation / Order Completeness

NARA is developing an in house job tracking order system to better coordinate work at the Branch level.

Item Level Evaluation: Automated File Characteristics 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

Category Technical Characteristic Warning/Pass/Fail or Logged Data
MPEG-2 File Format: Container Features
  • Video Tracks (number of)
  • Audio Tracks (number of)
  • Mismatch in Audio and Video Duration
Warning/Pass/Fail
  • File Size
  • Content Layout
  • PIDs Allowed for Audio and Video
Logged data
MPEG-2 File Format: Program Features Audio PID to Language Map Warning/Pass/Fail
MPEG-2 Video Essence: Video Description Features
  • Chroma Format
  • Frame Rate (Fps)
  • Picture Scanning Type
  • Scan Order
  • Frame Rate (Fps)
  • Resolution (Width/Height)
  • Resolution Change
  • Bits Per Pixel (Luma and Chroma)
  • Video Format
Warning/Pass/Fail
  • Average Bitrate (Mbps)
  • Duration
  • Pixel Aspect Ratio (PAR)
  • Display Aspect Ratio (DAR)
  • GOP structure
  • Active Pixels (Percentage)
Logged data
MPEG-2 Video Essence: Video Quality Features Video Signal Levels (Luma/Chroma) Warning/Pass/Fail
  • Color Bars
  • Black Bars
  • Freeze Frames
  • Brightness
  • Contrast
  • White Point
  • Cadence Break
  • Upconversion
  • Field Order
Logged data
MPEG-2 Video Structure
  • Profile
  • Level
  • GOP structure
Warning/Pass/Fail
  • Bitrate value (number)
  • Bitrate extension (number)
  • Top field first
  • Progressive sequence
  • Picture coding type
  • Picture structure
  • OP47 Data
  • Caption Data
  • VITC PAL/NTSC
  • WSS PAL
  • Subtitles in Teletext PAL
Logged data
MPEG-2 Audio Essence: Audio Description Features
  • Sampling Frequency (Hz)
  • Bitrate (Kbps)
  • Frame size (bpf)
  • Audio Channels (Number)
  • Bits per sample (Number)
Warning/Pass/Fail
  • LFE Channels (Number)
  • Sampling Frequency Change
  • Bitrate change
  • Audio channel number change
  • Duration
Logged data
MPEG-2 Audio Essence: Audio Quality Features
  • Maximum Level
  • Audio Clipping
Warning/Pass/Fail
  • Test Tone
  • Average Level
  • Phase Mismatch
  • Level Mismatch
  • Loudness
  • Misplaced Channels
  • Background Noise
  • Transient Noise
  • Wow and Flutter
  • Jitter Noise
  • High Frequency Noise
  • Overmodulation
  • Silence
    • Lead-in
    • During recorded audio
    • Lead-out
Logged Data
MPEG-2 Audio Structure
  • Layer
  • Audio coding mode
Warning/Pass/Fail
  • Audio coding mode change
  • ID3 tag
  • ID
Logged data

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