Video Maximum Manual Capture - HD [VID-P3]
Record Type: Digital Moving Images from Video Source Material
Expected Use: Preservation Master
Product Name: Video Maximum Manual Capture - HD [VID-P3]
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 high definition (HD) video with or without sound where there is a need to ensure that all significant visual and auditory information is carried forward. This includes HD digital videotape that cannot be extracted as data, but can be transcoded to a standardized digital file format. These formats are identified in section B2.4of International Association of Sound and Audiovisual Archives (IASA) TC-06 in Class 2.
Possible File Derivatives: This product is used to make HD MPEG-2 50MB 4:2:2 reproduction masters and distribution files.
File Properties
Container Format |
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Container: AVI (Audio Video Interleaved) |
File Specifications |
Target Total Bitrate: ~1065 Mbps Timecode: Source LTC/VITC Video data
Audio data
Typical file size: ~7987 MB/minute or 479.25 GB/hour |
Quality Control
Quality Assurance and Quality Control for HD AVI Video Products
The National Archives and Records Administration (NARA) uses a commercially available, automated batch processing software tool to evaluate specific quality metrics. Below is an outline of our current processes for HD AVI formatted products.
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.
Embedded metadata: NARA is working to develop embedded metadata guidelines for reformatted video. Additional information will be added to this site when available.
Technical metadata: NARA uses its reVTMD schema for video technical metadata.
Item Level Evaluation: Automated File Characteristics Analysis
Fixity: NARA creates a checksum on the local workstation where the file is created. This checksum is verified once the file reaches long-term tape storage to ensure that no changes have occurred during quality assurance (QA)/quality control (QC) procedures and file transfers on networked storage.
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 HD AVI products.
Terms used in the QC protocols are defined in the Glossary of Terms.
Container technical characteristics checked or logged include:
Check (Warning/Pass/Fail) |
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Logged data |
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Video technical characteristics checked or logged include:
Check (Warning/Pass/Fail) |
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Logged data |
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Audio technical characteristics checked or logged include:
Check (Warning/Pass/Fail) |
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Logged data |
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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 HD preservation master product option. All video is ingested on equipment that is calibrated to allow for ITU-R Recommendation BT.709 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 wrapper and codec was one that NARA staff looked at very critically. We continue to monitor developments in the area of wrapper, codec and toolset development. We see AVI, MOV, MXF, and MKV as the most viable options. Each has pros and cons. 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.
The digital preservation master products produced by the Audio-Video Preservation Lab are in line with published guidelines and best practices including the IASA TC-06: Guidelines for the Preservation of Video Recordings.
NARA’s options for reproduction masters are in line with peer institutions.