FreeCalypso > hg > gsm-codec-lib
view libtwamr/sqrt_l.tab @ 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 | 8dfb7cbe6b59 |
| children |
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/* ******************************************************************************** * * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001 * R99 Version 3.3.0 * REL-4 Version 4.1.0 * ******************************************************************************** * * File : sqrt_l.tab * Purpose : Table for routine sqrt_l_exp() * $Id $ * ******************************************************************************** */ /* table[i] = sqrt((i+16)*2^-6) * 2^15, i.e. sqrt(x) scaled Q15 */ static const Word16 table[49] = { 16384, 16888, 17378, 17854, 18318, 18770, 19212, 19644, 20066, 20480, 20886, 21283, 21674, 22058, 22435, 22806, 23170, 23530, 23884, 24232, 24576, 24915, 25249, 25580, 25905, 26227, 26545, 26859, 27170, 27477, 27780, 28081, 28378, 28672, 28963, 29251, 29537, 29819, 30099, 30377, 30652, 30924, 31194, 31462, 31727, 31991, 32252, 32511, 32767 };