Differential Pulse Code Modulation (DPCM)
Complete Definition
DPCM is and advanced form of PCM.
Differential (or Delta) pulse-code modulation (DPCM) encodes the PCM values as differences between the current and the previous value. For audio this type of encoding reduces the number of bits required per sample by about 25% compared to PCM. Predict the next sample based on the last few decoded samples.
Wikipedia Definition of Delta Modulation
Wikipedia Definition of DPCM
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