8-bit signed integers are represented in two's complement notation; the highest bit is the sign: 0 for positive, 1 for negative. So the highest positive number that can be represented is 127.
Setting one of the YUV offsets to -128 or +128 causes the firmware to contains the same 0x80 value, the SJ8 Pro considers that number as negative, as expected.
8-bit signed integers are represented in two's complement notation; the highest bit is the sign: 0 for positive, 1 for negative. So the highest positive number that can be represented is 127. Setting one of the YUV offsets to -128 or +128 causes the firmware to contains the same 0x80 value, the SJ8 Pro considers that number as negative, as expected.