If bit at Src[i] <> 0 then Integer (32, 16 or 8bit) at index "i" in the calling vector is set to 1. 

Returns the result of bit unpacking the bits stred Src values [0]..[Len-1] and stored in the calling object (Self) values [Index]..[Index+Len-1]. The storage precision of the calling object is preserved. The Len parameter specifies the number of bits that will be unpacked from Src. Unpack to array with precision other than Int32 is 8x slower.

BitUnpack Method