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 Digital Preservation Framework Category/Categories NARA Format ID NARA Linked Open Data TTL
Adaptive Multi Rate Audio (AMR) Digital Audio NF00102
Advanced Audio Coding (AAC) MPEG-2 Audio Digital Audio NF00106
Advanced Audio Coding MPEG-4 Low Complexity Object Digital Audio NF00108
Advanced Systems Format unspecified version Digital Video|Digital Audio NF00109
Apple Soundtrack Pro Project Digital Audio NF00815
Audio Interchange Format (AIFF) Digital Audio NF00115
Audio Interchange Format with LPCM Audio Digital Audio NF00116
Avid Pro Tools Session 5.1-6.9 Digital Audio NF00817
Broadcast Wave (BWF) unspecified version Digital Audio NF00650
Broadcast Wave (BWF) v. 0 Digital Audio NF00136
Broadcast Wave (BWF) v. 1 Digital Audio NF00539
Broadcast Wave (BWF) v. 2 Digital Audio NF00540
Exchangeable Image File Format Audio 2.2 Digital Audio NF00176
Free Lossless Audio Codec (FLAC) Digital Audio NF00198
IRCAM Sound File Digital Audio NF00816
MPEG Audio Layer 2 Digital Audio NF00597
MPEG-1 Audio Layer 1 Digital Audio NF00596
MPEG-1 Audio Layer 3 Digital Audio NF00335
MPEG-4 File Format, V.2, with Advanced Audio Coding Digital Audio NF00107
NCH Dictation Audio File Digital Audio NF00600
Pulse Code Modulated Digital Audio NF00603
QuickTime Audio with AAC codec Digital Audio NF00392
RealAudio Digital Audio NF00604
RealMedia Digital Audio|Digital Video NF00396
RealMedia metafile Digital Audio|Digital Video NF00397
Sound Designer II Audio File Digital Audio NF00407
SoundFont 2 Sound Bank Digital Audio NF00814
Waveform Audio File Format (WAVE) PCMWAVEFORMAT Digital Audio NF00531
Waveform Audio File Format (WAVE) WAVEFORMATEX Digital Audio NF00532
Waveform Audio File Format (WAVE) with LPCM Audio Digital Audio NF00438
Windows Media Audio unspecified version Digital Audio NF00446