The Adaptive Delta Pulse Code Modulation (ADPCM, also "adaptive differential pulse code modulation") compression scheme from Microsoft provides for basic audio compression of raw audio data, making audio WAV files smaller.
Microsoft's ADPCM audio compression stores WAV data in 1/4 the space of an uncompressed WAV. While the codec produces good quality sound in low frequency ranges, high frequency ranges at low sampling rates (e.g. 11 KHz) show noticable distortion, but is not noticable at sampling rates at or above 44.1 KHz. "Delta" or "differential" refers to how the codec stores differences (i.e. a "delta" or change value) between adjacent PCM samples.
Microsoft (Need to search)
For ALPlayer information and support, please visit ALTools.