Audio - Revision history

Courtney at 21:14, 13 February 2013

2013-02-13T21:14:38Z

Evelyn McLellan at 18:27, 11 May 2010

2010-05-11T18:27:07Z

Peter at 15:46, 2 May 2010

2010-05-02T15:46:53Z

Evelyn McLellan at 21:04, 16 March 2010

2010-03-16T21:04:43Z

Evelyn McLellan at 21:03, 15 March 2010

2010-03-15T21:03:40Z

Evelyn McLellan at 20:24, 15 March 2010

2010-03-15T20:24:08Z

Evelyn McLellan at 20:22, 15 March 2010

2010-03-15T20:22:50Z

Evelyn McLellan at 20:09, 15 March 2010

2010-03-15T20:09:16Z

Evelyn McLellan at 20:04, 15 March 2010

2010-03-15T20:04:03Z

Evelyn McLellan at 19:07, 15 March 2010

2010-03-15T19:07:06Z

← Older revision		Revision as of 21:14, 13 February 2013
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−	[[Main Page]] > [[Documentation]] > [[~~Media type preservation plans~~]] > Audio	+	[[Main Page]] > [[Documentation]] > [[Format policies]] > Audio

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 ==Comments==
-*For the preservation master, audio files are normalized to WAVE LPCM with a bit depth of 16 bits per sample and a sampling frequency of 44100 HZ.
+*For the preservation master, audio files are normalized to WAVE LPCM with a bit depth of 16 bits per sample. The sampling frequency of the original file is maintained. If the ingested file has a bit depth of greater than 16, normalization will be adjusted to use the higher bit depth.
 **Library of Congress considers WAVE LPCM as the "preferred format for sound recordings." [http://www.digitalpreservation.gov/formats/fdd/fdd000002.shtml Library of Congress Sustainability of Digital Formats: WAVE Audio File Format with LPCM audio]
 **Florida Digital Archive normalizes audio streams contained in WAVE files to uncompressed PCM(LPCM) with a bit depth of 16 bits per sample. See [http://www.fcla.edu/digitalArchive/formatInfo.htm Preservation action plans: WAVE].

← Older revision		Revision as of 15:46, 2 May 2010
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−	==[[Significant ~~properties~~ of audio files]]==	+	==[[Significant characteristics of audio files]]==

	==Preservation Format==		==Preservation Format==

@@ Line 14: / Line 14: @@
 ==Comments==
-*For the preservation master, audio files are normalized to WAVE LPCM with a bit depth of 16 bits per sample and a sampling frequency of 44000 HZ.
+*For the preservation master, audio files are normalized to WAVE LPCM with a bit depth of 16 bits per sample and a sampling frequency of 44100 HZ.
 **Library of Congress considers WAVE LPCM as the "preferred format for sound recordings." [http://www.digitalpreservation.gov/formats/fdd/fdd000002.shtml Library of Congress Sustainability of Digital Formats: WAVE Audio File Format with LPCM audio]
 **Florida Digital Archive normalizes audio streams contained in WAVE files to uncompressed PCM(LPCM) with a bit depth of 16 bits per sample. See [http://www.fcla.edu/digitalArchive/formatInfo.htm Preservation action plans: WAVE].

@@ Line 17: / Line 17: @@
 **Library of Congress considers WAVE LPCM as the "preferred format for sound recordings." [http://www.digitalpreservation.gov/formats/fdd/fdd000002.shtml Library of Congress Sustainability of Digital Formats: WAVE Audio File Format with LPCM audio]
 **Florida Digital Archive normalizes audio streams contained in WAVE files to uncompressed PCM(LPCM) with a bit depth of 16 bits per sample. See [http://www.fcla.edu/digitalArchive/formatInfo.htm Preservation action plans: WAVE].
-**According to [http://www.carli.illinois.edu/mem-prod/contentdm/guidelines_for_audio.pdf Guidelines for the Creation of Digital Collections: Digitization Best Practices for Audio, Consortium of Academic and Research Libraries in Illinois, 2009], WAVE LPCM with with a bit-depth of 16 bits and a sampling freqency of 44000 HZ is the minimum standard for a preservation format (p. 2). Higher bit depth and sampling frequencies may be desirable: "Several specific reasons for richer files include: the accurate capture of noise like clicks, pop, and other inaudible information that resides in frequencies higher than 44.1 kHz; desire to communicate inaudible harmonic information that impact perception of sound; ability to record and provide content that, although not necessarily heard, helps listeners understand and hear better space, depth, and instrument location in stereo and surround sound recordings; and to accommodate future user applications." (p.1)
+**According to [http://www.carli.illinois.edu/mem-prod/contentdm/guidelines_for_audio.pdf Guidelines for the Creation of Digital Collections: Digitization Best Practices for Audio, Consortium of Academic and Research Libraries in Illinois, 2009], WAVE LPCM with with a bit-depth of 16 bits and a sampling freqency of 44100 HZ is the minimum standard for a preservation format (p. 2). Higher bit depth and sampling frequencies may be desirable: "Several specific reasons for richer files include: the accurate capture of noise like clicks, pop, and other inaudible information that resides in frequencies higher than 44.1 kHz; desire to communicate inaudible harmonic information that impact perception of sound; ability to record and provide content that, although not necessarily heard, helps listeners understand and hear better space, depth, and instrument location in stereo and surround sound recordings; and to accommodate future user applications." (p.1)
 *For the access copy, audio files are normalized to MP3 using a bit-rate of 192 kbp/s.
 **According to [http://www.carli.illinois.edu/mem-prod/contentdm/guidelines_for_audio.pdf Guidelines for the Creation of Digital Collections: Digitization Best Practices for Audio, Consortium of Academic and Research Libraries in Illinois, 2009],"Access copies for audio files may be saved in compressed formats that allow for quicker transfer or streaming via the Internet. The MP3 format is widely-supported, is playable on nearly all handheld devices, and is commonly used for web delivery. MP3 is the preferred format. MP3 files saved at 192 Kbps (the bit-rate) are recommended for good quality compressed audio." (p.2)