FreeCalypso > hg > gsm-codec-lib
view libtwamr/bgnscd.c @ 415:01c4becb9fda
libtwamr: integrate pitch_ol.c
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Tue, 07 May 2024 03:01:01 +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 : bgnscd.c * Purpose : Background noise source charateristic detector (SCD) * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "bgnscd.h" #include "typedef.h" #include "basic_op.h" #include "no_count.h" #include "cnst.h" #include "memops.h" #include "gmed_n.h" #include "sqrt_l.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ /*-----------------------------------------------------------------* * Decoder constant parameters (defined in "cnst.h") * *-----------------------------------------------------------------* * L_FRAME : Frame size. * * L_SUBFR : Sub-frame size. * *-----------------------------------------------------------------*/ /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /* ************************************************************************** * * Function : Bgn_scd_reset * Purpose : Resets state memory * ************************************************************************** */ void Bgn_scd_reset (Bgn_scdState *state) { /* Static vectors to zero */ Set_zero (state->frameEnergyHist, L_ENERGYHIST); /* Initialize hangover handling */ state->bgHangover = 0; } /* ************************************************************************** * * Function : Bgn_scd * Purpose : Charaterice synthesis speech and detect background noise * Returns : background noise decision; 0 = no bgn, 1 = bgn * ************************************************************************** */ Word16 Bgn_scd (Bgn_scdState *st, /* i : State variables for bgn SCD */ Word16 ltpGainHist[], /* i : LTP gain history */ Word16 speech[], /* o : synthesis speech frame */ Word16 *voicedHangover /* o : # of frames after last voiced frame */ ) { Word16 i; Word16 prevVoiced, inbgNoise; Word16 temp; Word16 ltpLimit, frameEnergyMin; Word16 currEnergy, noiseFloor, maxEnergy, maxEnergyLastPart; Word32 s; /* Update the inBackgroundNoise flag (valid for use in next frame if BFI) */ /* it now works as a energy detector floating on top */ /* not as good as a VAD. */ currEnergy = 0; move16 (); s = (Word32) 0; move32 (); for (i = 0; i < L_FRAME; i++) { s = L_mac (s, speech[i], speech[i]); } s = L_shl(s, 2); currEnergy = extract_h (s); frameEnergyMin = 32767; move16 (); for (i = 0; i < L_ENERGYHIST; i++) { test (); if (sub(st->frameEnergyHist[i], frameEnergyMin) < 0) frameEnergyMin = st->frameEnergyHist[i]; move16 (); } noiseFloor = shl (frameEnergyMin, 4); /* Frame Energy Margin of 16 */ maxEnergy = st->frameEnergyHist[0]; move16 (); for (i = 1; i < L_ENERGYHIST-4; i++) { test (); if ( sub (maxEnergy, st->frameEnergyHist[i]) < 0) { maxEnergy = st->frameEnergyHist[i]; move16 (); } } maxEnergyLastPart = st->frameEnergyHist[2*L_ENERGYHIST/3]; move16 (); for (i = 2*L_ENERGYHIST/3+1; i < L_ENERGYHIST; i++) { test (); if ( sub (maxEnergyLastPart, st->frameEnergyHist[i] ) < 0) { maxEnergyLastPart = st->frameEnergyHist[i]; move16 (); } } inbgNoise = 0; /* false */ move16 (); /* Do not consider silence as noise */ /* Do not consider continuous high volume as noise */ /* Or if the current noise level is very low */ /* Mark as noise if under current noise limit */ /* OR if the maximum energy is below the upper limit */ test (); test (); test (); test (); test (); if ( (sub(maxEnergy, LOWERNOISELIMIT) > 0) && (sub(currEnergy, FRAMEENERGYLIMIT) < 0) && (sub(currEnergy, LOWERNOISELIMIT) > 0) && ( (sub(currEnergy, noiseFloor) < 0) || (sub(maxEnergyLastPart, UPPERNOISELIMIT) < 0))) { test (); if (sub(add(st->bgHangover, 1), 30) > 0) { st->bgHangover = 30; move16 (); } else { st->bgHangover = add(st->bgHangover, 1); } } else { st->bgHangover = 0; move16 (); } /* make final decision about frame state , act somewhat cautiosly */ test (); if (sub(st->bgHangover,1) > 0) inbgNoise = 1; /* true */ move16 (); for (i = 0; i < L_ENERGYHIST-1; i++) { st->frameEnergyHist[i] = st->frameEnergyHist[i+1]; move16 (); } st->frameEnergyHist[L_ENERGYHIST-1] = currEnergy; move16 (); /* prepare for voicing decision; tighten the threshold after some time in noise */ ltpLimit = 13926; /* 0.85 Q14 */ move16 (); test (); if (sub(st->bgHangover, 8) > 0) { ltpLimit = 15565; /* 0.95 Q14 */ move16 (); } test (); if (sub(st->bgHangover, 15) > 0) { ltpLimit = 16383; /* 1.00 Q14 */ move16 (); } /* weak sort of voicing indication. */ prevVoiced = 0; /* false */ move16 (); test (); if (sub(gmed_n(<pGainHist[4], 5), ltpLimit) > 0) { prevVoiced = 1; /* true */ move16 (); } test (); if (sub(st->bgHangover, 20) > 0) { if (sub(gmed_n(ltpGainHist, 9), ltpLimit) > 0) { prevVoiced = 1; /* true */ move16 (); } else { prevVoiced = 0; /* false */ move16 (); } } test (); if (prevVoiced) { *voicedHangover = 0; move16 (); } else { temp = add(*voicedHangover, 1); test (); if (sub(temp, 10) > 0) { *voicedHangover = 10; move16 (); } else { *voicedHangover = temp; move16 (); } } return inbgNoise; }