Digital Asset Management: Audio Standards
- Security and Permissions
- Software and Hardware
- File Storage
- File Naming
- Physical Format
- Digital Format
- Distribution Aspects
- Archival Aspects
- File Extension Standards
- Project Planning
- Copyright FAQ (Coming soon!)
Questions regarding the legal use of digital media are answered in a Copyright FAQ and such use must be guided by several policies and procedures that include the College’s Intellectual Property Policy, and Information technology policies. Misusing those rights places both you and the College in jeopardy. “Fair use” standards for visual materials are especially rigorous, and you must be certain that the intended uses in your digitization project do not infringe on the rights of others.
In the case of audio, these other legal rights may apply:
- Performance rights (live, or an existing recording played for the public; the College has blanket agreements with ASCAP, BMI, and SESAC)
- Grand rights (royalties for musical theater works)
- Mechanical rights (for the production and distribution of recordings, including over the internet). Note: Typically a single recording of an audio performance for archival purposes does not involve any additional legal agreements under the principle of "fair use".
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One of the strengths of digitizing resources is that it makes those resources accessible to many people. However, that strength can become a weakness if proper security is not put in place. In addition to institutional security practices there are several different strategies that should be built into any digital project.
- access to archival master files should be limited.
- workflow should prevent any changes to the master files.
- derivative files should be the ones delivered to users.
- there should be a clear copyright statement attached to all files
All faculty, staff, and students must comply with Bowdoin’s Information Technology policies as outlined under the heading "College-wide" at http://www.bowdoin.edu/about/admin/
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- Purchase of audio - varies greatly, between $30.00-$200.00 per audio recording (not including public performance rights), depending upon vendor/title
- Hardware and software – contact IT
- File storage – contact IT
- Staff time - when beginning an audio conversion project, you should consider that it can take up to 2 hours per 1 hour audio recording to convert, edit and manage. Moreover, audio conversion uses a significant amount of processing power and special equipment might be needed depending on the analog audio format. For these reasons, we recommend investigating outsourcing options for audio conversion projects. Consult with IT to identify reputable vendors or obtain recommendations or referrals.
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Software and Hardware Standards
Because computer models, peripherals, scanners and software versions change so quickly, it is important that you contact IT to get the most recent standards. The staff will assist you in selecting the correct equipment for your project.
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To promote reliable searching and basic media and file management practices, Bowdoin College recommends the use of the Public Broadcasting Core (PBCore) descriptive metadata standard for recorded sound. This standard is based on Dublin Core (see Bowdoin recommended standards for digital still images) but has greater complexity, incorporating more technical fields and the ability to encompass description of multiple physical and digital formats of the same media item. The PBCore allows for a wide range of detail, from very simple to extremely specific.
See www.pbcore.org for more detailed descriptions and examples
|Field||*Required?||Definition||Examples||PBCore element||DC element|
|Descriptive and administrative metadata|
|Metadata record ID||M (PBC M)||Unique ID of record of metadata descriptions for a media item||Record ID in digital asset management system; may be automatically generated||identifier (01.01)||No equivalent|
|Metadata record creator||M (PBC M)||Agency, institution or individual that assigns Metadata record ID||Bowdoin College Library||identifierSource (01.02)||No equivalent|
|Date created||M||Date of capture/creation||recording date, digitization date||dateCreated (25.01)||date|
|Creator or Author||MA||An entity responsible for the creation of the work||performer; producer||creator (15.01)||creator|
|Title||M||Formal name given to the work or brief caption for untitled work||Bowdoin Concert Band performanceSpring 2003; Inuit in South Greenland, 1947||title (02.01)||title|
|Administrative Control||M||An entity responsible for the content of the work||A dept. or office that has custody of the work||rightsSummary (18.01)||rights|
|IP Rights||MA||Information about the copyright and related intellectual property rights||Name of copyright holder; terms defining use and governing access to the work||rightsSummary (18.01)||rights|
|Description||M (PBC M)||Brief summary of the content of the work||Free text narrative of the contents and/or context of the media||Description (4.01)||description|
|Keyword||O||Topic of the content||Topical keywords or controlled vocabulary||subject (3.01)||subject|
|Publisher||O||An entity responsible for making the work available||A person; a dept. or office; the College||publisher (17.01)||publisher|
|Use||O||Intended audience||Class no.; project name||audienceLevel (18.01)||audience|
|Location||M (PBC M)||Location of media||URL; shelf location||formatLocation (25.05)||No equivalent|
|Media Identifier||M (PBC M)||Unique identifier of media item such as file name or call number||BA583 filename.mp3||formatIdentifier (25.25.1)||identifier|
|Media Identifier Source||M (PBC M)||Agency, institution or individual that assigns Media ID||Bowdoin College. IT||formatIdentifierSource (25.25.2)||No equivalent|
|Physical Format||M||Physical medium||CD, DVD-RW, Digital Audio Tape||formatPhysical (25.03)||format - medium|
|Digital format||M||Identify format of media item as it exists in digital form||mpeg; RealAudio||Formatdigital (25.04)||format|
|Media type||M||General descriptor of the kind of media||Sound||formatMediaType (25.06)||type|
|Generation of Media||MA||original, master, copy||Preservation master, original recording||formatGenerations (25.07)||format|
|Format Standard||M||Identify larger system/technical standard within which media exists||MPEG, Quicktime||formatStandard (25.08)||relation – conformsTo|
|Format Encoding||M||How information in media item is compressed, interpreted or formulated||MPEG-1 Real Media||formatEncoding (25.09)||format|
|Tracks||O||Number of tracks present||3 audio tracks||formatTracks (25.20)||format – extent|
|Channel Configuration||O||Arrangement or configuration of specific channels or layers of information||Stereo, monaural||fomatChannelConfiguration (25.21)||format|
|Recording equipment||MA||Equipment or software? used to create media||Make and model of recording equipment; name and version of software||Local use – no equivalent||Local use – no equivalent|
- Mandatory if applicable
- (PBC M)
- PBCore mandatory
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File Storage Standards
Please call IT to discuss file storage needs.
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File Naming Standards
- Length: 32 or fewer characters, including the extension
- Include three letter extensions (e.g., “.mp3”)
- Use only one period in a file name, and position it before the three-letter extension; if there is no extension, then do not use any periods in the filename.
- Use only the characters from the following sets: a-z, 0-9, hyphen ( - )
- Use all lower case letters
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Physical Format Standards
The DVD format, because it both produces a high quality sound and has been widely adopted by manufacturers and users of consumer-level audio equipment, is the recommended audio format for Bowdoin College students, faculty, and staff. The DVD uses high density media to record audio tracks, and is easily transferable to either a PC or to a Mac platform.
Bowdoin College Information Technology and the Library’s Language Media Center support DVD playback and editing, and the Library’s Special Collections and Archives is able both to play DVD's and to convert them to other formats (network/web file, iTunes U) for distribution or for classroom use.
Recommended Audio Setting for Video Recording
To ensure better compatibility among miniDV playback devices, it is recommended that miniDV cameras have their audio set to 16 bits. Selection of higher bit depths can jeopardize audio playback on some machines.
Digital File Format Standards
These recommendations are based on established format protocols currently used to deploy media content to the Bowdoin Web site and other Web-based applications. I.e., Blackboard, e-Reserves, iTunes U, Podcasts, Bowdoin web site.
Recommended Media Containers
Bowdoin's baseline standard for both open and commercial software audio formats is based on MPEG-4 Part 14. MPEG-4 Part 14 is a multimedia container format standard specified as a part of MPEG-4. It is most commonly used to store digital audio and digital video data, especially those defined by MPEG, but can also be used to store other data such as subtitles and still images. Additionally, MPEG-4 Part 14 also allows streaming over the Internet and is compatible with current server hardware installed at Bowdoin. The official filename extension for MPEG-4 Part 14 files is .mp4, thus the container format is typically referred to as MP4. The only exception to Bowdoin's baseline standard for an open audio format is MPEG-1 Audio Layer 3, more commonly referred to as MP3. MP3 audio is used to guarantee successful delivery of digital audio to the widest variety of computer platforms and mobile devices, such as MP3 players, iPods and cellular phones. To determine which media container to use, please consult with IT.
Recommended Software Platform
Quicktime is the recommended software platform for encoding and decoding of media content, but other encoders are freely and openly available to encode media into the recommended containers. Additionally, Quicktime is freely available to the public for both PC and Macintosh computer platforms and is currently the most used encoding engine for mobile video and audio devices (such as iPods). Quicktime also allows Bowdoin to leverage server side solutions, such as Apple's Podcast Producer, to automate the encoding, and deployment of media content in support of web related applications.
MP4 and QuickTime Benefits
The primary reason behind the selection of Quicktime as the recommended software platform is because both the MOV and MP4 containers can use the same MPEG-4 codecs, and are mostly interchangeable in a QuickTime-only environment. However, MP4, being an international standard, has more open support. This is especially true on most hardware devices.
Additionally, QuickTime's MPEG-4 Export dialog contains an option called "Passthrough" which allows a clean export to MP4 without affecting the audio or video streams. The MOV file format supports multichannel audio with more than two channels while QuickTime's support for audio in the MP4 container is limited to stereo. Therefore multichannel audio must be re-encoded during MP4 export.
Distributing Digital Audio
Digital audio can be distributed via physical media or the internet. Tape is not a suitable physical medium to be used for distribution. When distributing audio recorded on tape, alternative formats, such as DVD or a computer file (see recommendations below), are recommended. For more information about audio captured during video recording, consult the video guidelines.
Tape and personal hard drives work well for short term capturing of digital audio, but this technology is not ideally suited to archival preservation. Magnetic media are inherently unstable and will, over time, begin to decay, thereby compromising the integrity of the source material. In addition, given the “all or nothing” nature of digital recording – data is either readable or it is not – relatively minor tape decay or deformation caused by repeated use or file corruption can render digital audio unusable. This is unlike analog tape recordings, which may exhibit sound distortions when the tape has begun to decay or has been deformed, but, depending on the severity of the distortions, still allow the possibility of listening to damaged source material.
In order to minimize the risk that an audio recording is lost due to decay or damage of the master, members of the Bowdoin community are recommended to preserve digital media in more than one format. A DVD can be used as a short term back-up for a master, but because DVDs are created using a compression algorithm, which produces audio of diminished quality from the original, and because DVDs are prone to “bronzing” as the inner foil is exposed to air and playback is compromised, DVDs should not be used as the primary archival storage media. It is recommended that in addition to the master, a computer file of the audio also be maintained on the Bowdoin network (see recommendations below).
File Extension Standards
MPEG-4 (.mp4, .m4a, .m4b)
MPEG-4 audio and video files generally use the standard .mp4 extension. Audio only MPEG-4 files typically use the standard .m4a extension. Digital audiobooks are typically use the .m4b extensions
MPEG-1 Audio Layer 3 (.mp3)
MPEG-1 Audio Layer 3 audio files use the .mp3 extension.
Downloadable Audio (.mov)
Audio purposed for download on the Bowdoin web site and related web applications should make use of Quicktime and the .mov extension to offer the best possibility of successful playback.
Streaming Audio (.mp4, .mov)
Audio purposed for streaming playback on the Bowdoin web site and related web applications should make use of Quicktime and the .mov extension to offer the best possibility of successful playback.
Mobile Audio (.mp3, .m4a)
Audio purposed for download and listening on mobile devices (such as iPods and iPhones) should use the .mp3 extension to offer the best possibility of successful playback.
Mobile Video with Sound (.m4v)
Video purposed for download and viewing on mobile devices may also include audio content, and should make use of Quicktime and the .m4v extension to offer the best possibility of successful playback.
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Project Planning Standards
Use of Basecamp, a powerful web-based project management tool is strongly recommended. To set up your project, contact email@example.com.
The plan should specify the following:
- Who will acquire, process and catalog the audio
- What campus facilities may be available for performance and/or recording
- The approximate number of hours of audio
- Who will use the audio
- How the audio will be accessed and by whom
- How the collection will be searched and sorted
- What copyright restrictions apply
- How many hours the project will require
- What hardware and software, (if any), needs to be purchased.
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