What is the algorithm of converting pcm to adpcm?

What is the algorithm of converting 开发者_运维技巧pcm to adpcm?

ADPCM refers to a family of compression algorithms (mostly used for voice compression on phone lines). Sometimes known as G.721 and G.732 (and others).

See http://www.javvin.com/protocolG7xx.html for more information. The spec for IMA ADPCM, which is the one that Microsoft implemented on Windows is available as photo-scans at Columbia university http://www.cs.columbia.edu/~hgs/audio/dvi/

PCM is uncompressed audio.