Audio Maximum Capture [AUD-P1]
|Record Type||Audio Recordings|
|Expected Use||Preservation Master|
|Product Name||Audio Maximum Capture [AUD-P1]|
The purpose of this product is to mitigate the risk of 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||
Analog recordings with a wide dynamic range, of high content value and/or of a complex nature and material of limited quantity and high cultural/historical significance where there is a need to ensure that all significant auditory information is carried forward. Examples include recordings where unique music is the primary focus and oral histories/interviews where background noise or other ambient noise is vital to capture.
|File Properties||Data Format|
Typical file size
Mono: ~ 17.28 MB/minute or 1 GB/hour
|Possible File Derivatives||
This master file can be used to create any preservation, reproduction or distribution file of equal or lesser capture quality.
Using these capture parameters, the resulting file sizes are generally three times larger than, for example, files of Audio Median Capture [AUD-R1].
This file will not be altered in any capacity except for level adjustment to be employed at the initial capture stage.
Quality Control for Digital Audio Files
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 WAV and MP3 products.
Item Level Evaluation: Automated Quality 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.
The digital preservation masters products produced by the Audio Preservation Lab are in line with published guidelines and best practices including the IASA TC-04: Guidelines for the Production and Preservation of Digital Audio Objects and ARSC Preservation of Archival Sound Recordings.
Reproduction masters are also BWF files but at the minimum CD Quality specification.
Distribution copies include a CD output option as well as an online delivery option.