FreeCalypso > hg > gsm-codec-lib
view doc/EFR-testing @ 183:452c1d5a6268
libgsmefr BFI w/o data: emit zero output after decoder reset
In real-life usage, each EFR decoder session will most likely begin
with lots of BFI frames before the first real frame arrives. However,
because the spec-defined home state of the decoder is speech rather
than CN, our regular logic for BFI w/o data would have to feed
pseudorandom noise to the decoder (in the "fixed codebook excitation
pulses" part), which is silly to do at the beginning of the decoder
session right out of reset. Therefore, let's check reset_flag_old,
and if we are still in the reset state, simply emit zero output.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Tue, 03 Jan 2023 00:12:18 +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.