SND (.snd)


    • Registered MIME type: audio/basic
    • SND audio format.
    • Used for digital audio in computer and telecommunication systems and on the web.
    • Supports a variety of audio codecs, including lossless uncompressed PCM, μ-law, a-law, and ADPCM voice compression.
    • Sometimes referred to as μ-law format or Unix Audio Format.
    • The μ-law algorithm is a standard method for compressing the dynamic range of a signal.
    • SND is an acronym derived from Sound.
    • Binary file format.
    • Supports various sampling frequencies and an arbitrary number of channels.
    • Identical to the AU format.
    • Developed by Sun Microsystems in 1992.

Import & Export

  • Import["file.snd"] imports an SND file, returning an audio object.
  • Import["file.snd",elem] imports the specified element from an SND file.
  • The import format can be specified with Import["file","SND"] or Import["file",{"SND",elem,}].
  • Export["file.snd",expr] exports an audio or sound object to an SND file.
  • Sound objects including notes are rasterized to sampled audio.
  • See the reference pages for full general information on Import and Export.
  • ImportString and ExportString support the SND format.

Import Elements

  • General Import elements:
  • "Elements"list of elements and options available in this file
    "Rules"full list of rules for each element and option
    "Options"list of rules for options, properties, and settings
  • Data representation elements:
  • "Audio"audio signal given as an Audio object
    "AudioFile"audio signal given as an out-of-core Audio object
    "Data"raw audio samples, given as a list of real numbers, each sublist representing an individual audio channel
    "SampledSoundList"audio signal given as a SampledSoundList object
    "Sound"audio signal given as a Sound object
  • Import and Export use the "Audio" element by default for SND files.
  • Advanced Import element:
  • "Duration"duration of the audio given in seconds
    "Length"number of samples
    "SampleDepth"number of bits used to store every sample
    "SampleRate"number of amplitude samples per second and channel


  • Import and Export option:
  • IncludeMetaInformationAllwhether to include meta-information
    SampleRateAutomaticnumber of samples per second for each channel
  • Detailed properties and settings:
  • "AudioChannels"Automaticthe number of audio channels in the file
    "AudioEncoding""Integer8"how samples are encoded
  • If the sample rate is not specified when exporting to SND, the highest sample rate occurring in the exported sound is used, and all sounds are resampled as necessary.
  • If the number of channels is unspecified, the highest number of simultaneous channels is taken, and silence is inserted if necessary.
  • If "AudioChannels" is set to a value n that is less than the number of channels to be exported, only the first n channels are exported.
  • The SND format supports PCM (pulse code modulation) and ADPCM (adaptive differential pulse code modulation) codecs, and various other audio encoding algorithms.
  • "AudioEncoding" can be set to any of the following codecs:
  • "Integer8"8-bit PCM
    "Integer16"16-bit PCM
    "Integer24"24-bit PCM
    "Integer32"32-bit PCM
    "Real32"32-bit IEEE floating point
    "Real64"64-bit IEEE floating point
    "aLaw"a-Law 4-bit PCM (ITU-T G.711)
    "uLaw"μ-Law 4-bit PCM (ITU-T G.711)
    "G721-32"32 kbps ADPCM (ITU G.721)
    "G723-24"G.723 encoding at 24 kbps
    "G723-40"G.723 encoding at 40 kbps
  • Not all codecs support arbitrary sample rates and channel specifications.


Basic Examples  (1)

Use Play to create a sound sample:

Click for copyable input

Export it to SND:

Click for copyable input
Introduced in 1999
Updated in 2016