G.727 is an ADPCM lossy compression that takes μ-Law (law=0) or A-Law (law=1) samples and compresses them to 2, 3, 4, or 5 bits per sample. The bits per sample are split into core bits and enhancement bits. The way it works is that the enhancement bits (least significant bits) may be removed from the encoding (bitshifted right) and the signal will still work with a reduced bitrate.
G.727 implementation from G.191 software tools at https://www.itu.int/rec/T-REC-G.191/en 2≤cbits≤4, ebits≥0, cbits+ebits≤5
