Preservation

Video Maximum Manual Capture - SD [VID-P1]

Record Type Digital Moving Images from Video Source Material
Expected Use Preservation Master
Product Name Video Maximum Manual Capture - SD [VID-P1]
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 standard definition analog video with or without sound where there is a need to ensure that all significant visual and auditory information is carried forward.

Current SAMMA Robotic system is restricted to ¾” U-matic tapes only. All other formats are processed on the Edius workstations.

File Properties Data Format

Container: AVI (Audio Video Interleaved)

Capture Information

Target Total Bitrate: ~177 Mbps

Timecode: Source LTC/VITC

Video data

  • Frame size: 720x486
  • Video codec: Uncompressed
  • Video frame rate: 29.97 fps
  • Color encoding: YUY2
  • Chroma format: 4:2:2
  • Interlaced scan

Audio data

  • Audio channels: 8 discrete (4 AES pairs)
  • Audio codec: PCM
  • Audio sample rate: 48 KHz
  • Audio sample size: 24 bit

Typical file size: ~ 1200 MB/minute or 72 GB/hour

Possible File Derivatives

This product is used to make SD MPEG-2 50MB 4:2:2 reproduction masters and distribution files.

Other Information

Due to its very large file size, this product is generally not accessed directly by researchers.

Audio and video levels may be adjusted as appropriate during the initial capture process but otherwise, the preservation files are unaltered. Reproduction and distribution files may have additional image improvements such as minimal color correction if necessary.

Quality Control Quality Assurance and Quality Control for SD AVI Format Products

NARA uses a commercially available, automated batch processing software tool to evaluate specific quality metrics. Below is a outline of our current processes for SD AVI 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.

Item Level Evaluation: Automated Quality Analysis

Using automated batch-processing software tools, test plans are developed for each format and/or each appropriate project. 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 as well as NARA defined aim points which may change depending on specific project goals. The following represents the quality test plan technical characteristics for AVI products.

Terms used in the QC protocols are defined in the Glossary of Terms.

Category Technical Characteristic Warning/Pass/Fail or Logged Data
AVI 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
AVI File Format Characteristics OpenDML AVI File Format Extension Warning/Pass/Fail
Uncompressed YUV Video Essence: Video Description Features
  • Chroma Format
  • Frame Rate (Fps)
  • Resolution (Width/Height)
  • Bits Per Pixel (Luma and Chroma)
  • Resolution Change
  • Video Format
Warning/Pass/Fail
  • Average Bitrate (Mbps)
  • Active Pixels (Percentage)
  • Duration
Logged data
Uncompressed YUV Video Essence: Video Quality Features Video Signal Levels (Luma/Chroma) Warning/Pass/Fail
  • Color Bars
  • Black Bars
  • Brightness
  • Contrast
  • White Point
  • Freeze Frames
  • Cadence Break
  • Upconversion
  • Field Order
Logged data
LPCM Audio Essence: Audio Description Features
  • Sampling Frequency (Hz)
  • Audio Channels (Number)
  • Bits per sample (Number)
  • Duration
Warning/Pass/Fail
  • Bit Rate (Kbps)
  • LFE Channels (Number)
Logged data
LPCM Audio Essence: Audio Quality Features
  • Maximum Level
  • Audio Clipping
Warning/Pass/Fail
LPCM Audio Essence: Audio Quality Features
  • Test Tone
  • Average Level
  • Phase Mismatch
  • Level Mismatch
  • Loudness
  • DialNorm-Loudness Mismatch
  • Misplaced Channels
  • Background Noise
  • Transient Noise
  • Wow and Flutter
  • Jitter Noise
  • High Frequency Noise
  • Overmodulation
Logged Data
Rationale

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

Currently, the Video Preservation Lab creates uncompressed video streams in an AVI (Audio Video Interleaved) wrapper for the SD preservation master product option. All video is ingested on equipment that is calibrated to allow for ITU-R Recommendation BT.601 compliance, but also to allow for safe capture of graphics and other computer-generated materials that may contain luminance values in the superwhite range. This method of calibration and capturing supports the most authentic replication of the original source material.

  • The choice of a wrapper was one that NARA staff looked at very critically. According to an in-house international survey conducted in the spring of 2010 of over 50 institutions involved with film and video reformatting, the three main choices for preservation products were AVI, QuickTime (.MOV) or MXF (Material Exchange Format). Each has pros and cons. Based on the feedback we received, NARA has decided to use the AVI wrapper for a variety of reasons including:
  • Both the robotic capture system as well as the manual capture system can natively capture in AVI. (Only the robotic capture system has the option to capture in MOV; the manual capture system cannot natively capture in MOV.)
  • While the AVI wrapper has somewhat limited support for timecode, we are able to capture a start timecode from which the remainder of a timecode track could be generated if required.
  • AVI files are playable in a wide variety of open source tools including VLC.

We will continue to monitor codec and wrapper use within the professional community as well as toolsets development and reevaluate our products as needed, especially when HD video reformatting comes to the fore.

NARA’s options for reproduction masters are in line with peer institutions.

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