FreeCalypso > hg > gsm-codec-lib
view doc/EFR-testing @ 604:54f0f1b74c25
libgsmhr1 TFO: require BFI=0 and SID=0 for homing
In order for a received frame to be recognized as DHF, we need
not only the correct bit pattern, but also BFI=0 and SID=0.
The BFI=0 requirement should be obvious, while the SID=0 requirement
is needed only for HR codec. With FR and EFR, SID classification
comes from the payload bits and no separate check is needed -
but in HR we get an out-of-band SID ternary flag. When SID=1,
no payload bits are used at all; when SID=2, we use only the first
33 bits of the payload. Therefore, it is proper to conditionalize
DHF acceptance on SID=0.
We already implemented this logic in the just finished full decoder;
now bring TFO code into agreement.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 04 Dec 2025 19:40:35 +0000 |
| parents | 1e8569000049 |
| children |
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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.