pub fn parse_212_format(buf: &[u8]) -> Vec<i16>
Parse a byte buffer of data in format 212, 12-bit two’s complement amplitude.
Two 12-bit samples in 3 bytes:
| 8 7 6 5 4 3 2 1 | 12 11 10 9 12 11 10 9 | 8 7 6 5 4 3 2 1 |