-- Byte order handling in libmseed --

The miniSEED 3 format is defined as little-endian headers with the
endianess of the data payload explicitly defined by the encoding
value.

The SEED 2.4 standard allows data only SEED (miniSEED) to be either in
big (most significant byte first) or little (least significant byte
first) endian byte order.  One exception is that Steim-1 and Steim-2
data compression are only defined as big-endian.

How libmseed determines the byte order of a 2.x record:

The byte order of a miniSEED 2.x record header including blockettes is
determined by checking if the record start year and day is a sane
value (e.g. year between 1900 and 2100 and day between 1 and 366).
The byte order of encoded data samples is determined by the byte order
flag in the Blockette 1000, if a Blockette 1000 is not present the
byte order is assumed to be the same as the header.

In what byte order libmseed creates 2.x records:

If the library ever creates miniSEED 2.x records, they will be in
big-endian byte order for maximum compatibility.