First byte stream: 247 * "128" + 9 * "127" Summed up over 256 samples and divided by 256: 0111 1111. 1111 0111 Rounded to 12bits: 0111 1111. 1111 Dropping the lowest two bits: 0111 1111. 11 ============= Second byte stream: 248 * "128" + 8 * "127" Summed up over 256 samples and divided by 256: 0111 1111. 1111 1000 Rounded to 12bits: 1000 0000. 0000 Dropping the lowest two bits: 1000 0000. 00 =============