Audio Specifications and Standards
The following provides a brief overview of our standard audio specifications.
Default File/Output Settings
- masters: .wav/WAVE at 24-bit/44.1khz
- note: IASA TC-04 calls for a minimum sampling rate of 48kHz (preferably 96kHz) . We will discontinue use of 44.1kHz sampling rates pending confirmation of appropriate storage space as 24/48 vs 24/44.1 should yield only an 8% increase in space requirements.- arora, 051309
- typically, 2s of silence is left or created at the beginning of each .wav, with 1s at the end.
- RMS levels are typically set fairly low, to -25db
- deliverables: .rm/RealAudio v. 8 at 16-bit/44.1kHz, 105 kbps (stereo)
- in the near future, our workflow will allow for some enhancement of the Real Audio files (dynamic range compression, higher RMS levels) in order for delivery of pragmatic derivatives; with the preservation .wav file unaffected by such enhancements.
Update 082809: Real Audio will not be the preferred delivery format as we began use of alternate delivery methods. MP3s will be created with the Lame Encoder using the following setting:
% lame sample.wav sample.mp3 -V4 --noreplaygain --nohist -S
These setting were decided upon after consulting the Hydrogen Audio site.
Resources and Links:
- Digitization and Preservation Standards
- TAPE (Training for Audiovisual Preservation in Europe). European Commission on Preservation and Access.
- Capturing Analog Sound for Digital Preservation: Report of a Roundtable Discussion of Best Practices for Tranferring Analog Discs and Tapes. (2006) Council on Library and Information Resources and Library of Congress.
- Sound Directions - project website, maintained by Indiana University Digital Library Program.
- Sound Directions: Best Practices for Audio Preservation. (2007) Casey, Mike & Bruce Gordon.
- Grammy foundation® Basic Methodology for Preservation, Conversion and Archiving Recorded Media. (revised 2008) Grammy Foundation, Santa Monica, CA.
- File Formats - from LOC Digital Preservation/Digital Formats site