FreeCalypso > hg > gsm-codec-lib
view libtwamr/prm2bits.c @ 605:63f774192906
gsmhr_decoder_twts002_in(): set BFI=1 SID=1 for invalid SID
When a received TW-TS-002 RTP payload indicates invalid SID,
which of the 3 possible BFI/SID combinations should we pass to
our internal ETSI-based speech decoder or TFO engine?
Our original code passed BFI=0 SID=1, but upon further reflection,
BFI=1 SID=1 is a better choice. In the corner case where received
invalid SID is fed to a full decoder in homed state, setting BFI=1
allows that decoder to emit zeros on PCM and stay homed, instead of
launching into full decoding.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 04 Dec 2025 21:01:46 +0000 |
| parents | ffd48f0a2ab5 |
| children |
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/* * A cleaner reimplementation of AMR Prm2bits() function. */ #include "typedef.h" #include "namespace.h" #include "bitno.h" #include "prm2bits.h" void Prm2bits(enum Mode mode, const Word16 prm[], Word16 bits[]) { const Word16 *t = bitno[mode]; unsigned nparam = prmno[mode]; unsigned n, p, mask; Word16 *b = bits; for (n = 0; n < nparam; n++) { p = prm[n]; mask = 1 << (*t++ - 1); for (; mask; mask >>= 1) { if (p & mask) *b++ = 1; else *b++ = 0; } } }
