Many parameters and data values are recorded in the C3D file as integer values. In the original C3D implementation, integer values in C3D files were always stored as 16-bit signed integers (that is numbers in the range of –32768 to +32767) and 8-bit signed bytes (a range of –128 to +127).
However, in many cases, the use of signed integers and bytes reduces the range available for parameter and data storage – as a result, it is common to find unsigned integers and bytes used in many C3D files.