FreeCalypso > hg > gsm-codec-lib
view libtwamr/b_cn_cod.h @ 482:5e2d849a4fbc
doc/Calypso-TCH-downlink: grammar fix
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Mon, 20 May 2024 01:24:22 +0000 |
parents | 07f936338de1 |
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 : b_cn_cod.h * Purpose : Contains function for comfort noise generation. * ******************************************************************************** */ #ifndef b_cn_cod_h #define b_cn_cod_h "$Id $" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" /* ******************************************************************************** * DEFINITION OF DATA TYPES ******************************************************************************** */ /* ******************************************************************************** * DECLARATION OF PROTOTYPES ******************************************************************************** */ /************************************************************************* * * FUNCTION NAME: pseudonoise * * PURPOSE: Generate a random integer value to use in comfort noise * generation. The algorithm uses polynomial x^31 + x^3 + 1 * (length of PN sequence is 2^31 - 1). * * INPUTS: *shift_reg Old CN generator shift register state * * * OUTPUTS: *shift_reg Updated CN generator shift register state * * RETURN VALUE: Generated random integer value * *************************************************************************/ Word16 pseudonoise ( Word32 *shift_reg, /* i/o : Old CN generator shift register state */ Word16 no_bits /* i : Number of bits */ ); /************************************************************************* * * FUNCTION NAME: build_CN_code * * PURPOSE: Compute the comfort noise fixed codebook excitation. The * gains of the pulses are always +/-1. * * INPUTS: *seed Old CN generator shift register state * * OUTPUTS: cod[0..39] Generated comfort noise fixed codebook vector * *seed Updated CN generator shift register state * * RETURN VALUE: none * *************************************************************************/ void build_CN_code ( Word32 *seed, /* i/o : Old CN generator shift register state */ Word16 cod[] /* o : Generated CN fixed codebook vector */ ); /************************************************************************* * * FUNCTION NAME: build_CN_param * * PURPOSE: Randomize the speech parameters. So that they * do not produce tonal artifacts if used by ECU. * * INPUTS: *seed Old CN generator shift register state * n_param, Number of parameters to randomize * parm_size_table, * * * OUTPUTS: parm CN Generated Parameters * *seed Updated CN generator shift register state * * RETURN VALUE: none * *************************************************************************/ void build_CN_param ( Word16 *seed, /* i/o : Old CN generator shift register state */ const Word16 n_param, /* i : number of params */ const Word16 param_size_table[], /* i : size of params */ Word16 parm[] /* o : CN Generated Params*/ ); #endif