Dialogic ADPCM or VOX is an
audio file format, optimized for storing
digitized voice data at a low
sampling rate. VOX files are most commonly found in
telephony applications, as well as an occasional arcade
redemption game.Similar to other
ADPCM (Adaptive Differential Pulse Code Modulation) formats, Dialogic ADPCM
compresses audio data into a series of 4-bit samples. Dialogic ADPCM files can have a sampling rate of 6000 or 8000 samples per second, but 8000 samples per second (8000Hz) is more common. Unlike a
WAV file, a VOX file does not contain a header to specify the encoding format or the sampling rate, so this information must be known in order to play the file. If not known, it is normally assumed that a VOX file is encoded with Dialogic ADPCM at a sampling rate of 8000Hz. It is possible that a VOX file may be encoded in a format other than Dialogic ADPCM, but this is not common.
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