Linked Open Data for Digital Audio Formats

The Digital Audio category encompasses formats used to encode recorded sound as machine readable files by converting acoustic sound waves into digital signals. Digital audio formats are generally composed of both a wrapper format, usually the common name associated with the file extension, and an encoding method or codec. Digital audio is defined as an audio waveform that has been created as, or converted into, digital form encoded as numerical samples in continuous sequence (i.e. sample depth over samples per second).

The significant properties of digital audio records are documented in a Digital Audio Preservation Plan, which can be used as test criteria for tools and processes used in format transformations.

NARA makes its Linked Open Data available in the Resource Description Framework Terse RDF Triple Language, or RDF Turtle (.ttl files). These files can be opened in any text editor. The Digital Preservation Framework as Linked Open Data includes the same elements as are available in the version of the Preservation Plans on GitHub.

These Plans are not exhaustive nor universally applicable proposed actions and recommended or endorsed tools: these represent file formats and variant versions in NARA holdings, the current NARA risk assessment, processing capabilities, and tools in use at NARA.


Format Name File Extension(s) Digital Preservation Framework Category/Categories NARA Format ID NARA Linked Open Data TTL
Adaptive Multi Rate Audio (AMR) amr Digital Audio NF00102
Advanced Audio Coding (AAC) MPEG-2 Audio aac Digital Audio NF00106
Advanced Audio Coding MPEG-4 Low Complexity Object aac|mp4|m4a Digital Audio NF00108
Apple Soundtrack Pro Project stmp Digital Audio NF00815
Audio Interchange Format (AIFF) aiff|aif Digital Audio NF00115
Audio Interchange Format with LPCM Audio aiff|aif Digital Audio NF00116
Avid Pro Tools Session 5.1-6.9 pts Digital Audio NF00817
Broadcast Wave (BWF) unspecified version wav Digital Audio NF00650
Broadcast Wave (BWF) v. 0 wav Digital Audio NF00136
Broadcast Wave (BWF) v. 1 wav Digital Audio NF00539
Broadcast Wave (BWF) v. 2 wav Digital Audio NF00540
Exchangeable Image File Format Audio 2.2 wav Digital Audio NF00176
Free Lossless Audio Codec (FLAC) flac Digital Audio NF00198
IRCAM Sound File sf Digital Audio NF00816
MPEG Audio Layer 2 mp2 Digital Audio NF00597
MPEG-1 Audio Layer 1 mp1 Digital Audio NF00596
MPEG-1 Audio Layer 3 mp3|x-mp3|mpeg3|mpeg|x-mpeg3|mpg|x-mpg|x-mpegaudio Digital Audio NF00335
MPEG-4 File Format, V.2, with Advanced Audio Coding aac Digital Audio NF00107
NCH Dictation Audio File dct Digital Audio NF00600
Pulse Code Modulated pcm|L16|wav|aiff|au Digital Audio NF00603
QuickTime Audio with AAC codec qta|aac|m4p|mp3 Digital Audio NF00392
RealAudio ra Digital Audio NF00604
RealMedia rm|rmf Digital Audio|Digital Video NF00396
RealMedia metafile ram Digital Audio|Digital Video NF00397
Sound Designer II Audio File sd2 Digital Audio NF00407
SoundFont 2 Sound Bank sf2 Digital Audio NF00814
Waveform Audio File Format (WAVE) PCMWAVEFORMAT wav Digital Audio NF00531
Waveform Audio File Format (WAVE) WAVEFORMATEX wav Digital Audio NF00532
Waveform Audio File Format (WAVE) with LPCM Audio wav Digital Audio NF00438
Windows Media Audio unspecified version wma Digital Audio NF00446