When it comes to codec libraries, testing for correctness is essential, and EFR
is no exception.  There is a set of EFR encoder and decoder test sequences
published by ETSI in ts_100725v050200p0.zip (GSM 06.54), and our suite of tools
includes gsmefr-etsi-enc and gsmefr-etsi-dec test programs that operate on the
representation formats used by these test sequences.  Because these test
programs are based on libgsmefr EFR_encode_frame() and EFR_decode_frame()
functions, seeing gsmefr-etsi-enc produce output that matches official ETSI
*.cod files proves that libgsmefr encoder is correct, and seeing gsmefr-etsi-dec
produce output that matches official ETSI *.out files proves that libgsmefr
decoder is correct.

For debugging, we also have gsmefr-cod-parse and gsmefr-dec-parse utilities that
parse ETSI *.cod and *.dec file formats and dump their content in human-readable
form similar to gsmrec-dump.

Please note that all ETSI test sequence file formats are endian-dependent: their
original programs read and write 16-bit words in the local machine's native byte
order, and whenever you are working with published test sequence files, you have
to check to see if they are BE or LE.  Our gsmefr-etsi-{enc,dec} and
gsmefr-{cod,dec}-parse programs support both byte orders; the default is LE
(matching the main parts of ts_100725v050200p0.zip), or you can select BE with
-b option.