| /* |
| * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. |
| * |
| * Use of this source code is governed by a BSD-style license |
| * that can be found in the LICENSE file in the root of the source |
| * tree. An additional intellectual property rights grant can be found |
| * in the file PATENTS. All contributing project authors may |
| * be found in the AUTHORS file in the root of the source tree. |
| */ |
| |
| /* |
| * This file contains the function for updating the background noise estimate. |
| */ |
| |
| #include "dsp.h" |
| |
| #include "signal_processing_library.h" |
| |
| #include "dsp_helpfunctions.h" |
| |
| /* Scratch usage: |
| Designed for BGN_LPC_ORDER <= 10 |
| |
| Type Name size startpos endpos |
| WebRtc_Word32 pw32_autoCorr 22 0 21 (Length (BGN_LPC_ORDER + 1)*2) |
| WebRtc_Word16 pw16_tempVec 10 22 31 (Length BGN_LPC_ORDER) |
| WebRtc_Word16 pw16_rc 10 32 41 (Length BGN_LPC_ORDER) |
| WebRtc_Word16 pw16_outVec 74 0 73 (Length BGN_LPC_ORDER + 64) |
| |
| Total: 74 |
| */ |
| |
| #if (BGN_LPC_ORDER > 10) && (defined SCRATCH) |
| #error BGN_LPC_ORDER is too large for current scratch memory allocation |
| #endif |
| |
| #define SCRATCH_PW32_AUTO_CORR 0 |
| #define SCRATCH_PW16_TEMP_VEC 22 |
| #define SCRATCH_PW16_RC 32 |
| #define SCRATCH_PW16_OUT_VEC 0 |
| |
| #define NETEQFIX_BGNFRAQINCQ16 229 /* 0.0035 in Q16 */ |
| |
| /**************************************************************************** |
| * WebRtcNetEQ_BGNUpdate(...) |
| * |
| * This function updates the background noise parameter estimates. |
| * |
| * Input: |
| * - inst : NetEQ instance, where the speech history is stored. |
| * - scratchPtr : Pointer to scratch vector. |
| * |
| * Output: |
| * - inst : Updated information about the BGN characteristics. |
| * |
| * Return value : No return value |
| */ |
| |
| void WebRtcNetEQ_BGNUpdate( |
| #ifdef SCRATCH |
| DSPInst_t *inst, WebRtc_Word16 *pw16_scratchPtr |
| #else |
| DSPInst_t *inst |
| #endif |
| ) |
| { |
| const WebRtc_Word16 w16_vecLen = 256; |
| BGNInst_t *BGN_Inst = &(inst->BGNInst); |
| #ifdef SCRATCH |
| WebRtc_Word32 *pw32_autoCorr = (WebRtc_Word32*) (pw16_scratchPtr + SCRATCH_PW32_AUTO_CORR); |
| WebRtc_Word16 *pw16_tempVec = pw16_scratchPtr + SCRATCH_PW16_TEMP_VEC; |
| WebRtc_Word16 *pw16_rc = pw16_scratchPtr + SCRATCH_PW16_RC; |
| WebRtc_Word16 *pw16_outVec = pw16_scratchPtr + SCRATCH_PW16_OUT_VEC; |
| #else |
| WebRtc_Word32 pw32_autoCorr[BGN_LPC_ORDER + 1]; |
| WebRtc_Word16 pw16_tempVec[BGN_LPC_ORDER]; |
| WebRtc_Word16 pw16_outVec[BGN_LPC_ORDER + 64]; |
| WebRtc_Word16 pw16_rc[BGN_LPC_ORDER]; |
| #endif |
| WebRtc_Word16 pw16_A[BGN_LPC_ORDER + 1]; |
| WebRtc_Word32 w32_tmp; |
| WebRtc_Word16 *pw16_vec; |
| WebRtc_Word16 w16_maxSample; |
| WebRtc_Word16 w16_tmp, w16_tmp2; |
| WebRtc_Word16 w16_enSampleShift; |
| WebRtc_Word32 w32_en, w32_enBGN; |
| WebRtc_Word32 w32_enUpdateThreashold; |
| WebRtc_Word16 stability; |
| |
| pw16_vec = inst->pw16_speechHistory + inst->w16_speechHistoryLen - w16_vecLen; |
| |
| #ifdef NETEQ_VAD |
| if( !inst->VADInst.VADEnabled /* we are not using post-decode VAD */ |
| || inst->VADInst.VADDecision == 0 ) |
| { /* ... or, post-decode VAD says passive speaker */ |
| #endif /* NETEQ_VAD */ |
| |
| /*Insert zeros to guarantee that boundary values do not distort autocorrelation */ |
| WEBRTC_SPL_MEMCPY_W16(pw16_tempVec, pw16_vec - BGN_LPC_ORDER, BGN_LPC_ORDER); |
| WebRtcSpl_MemSetW16(pw16_vec - BGN_LPC_ORDER, 0, BGN_LPC_ORDER); |
| |
| w16_maxSample = WebRtcSpl_MaxAbsValueW16(pw16_vec, w16_vecLen); |
| w16_tmp = 8 /* log2(w16_veclen) = 8 */ |
| - WebRtcSpl_NormW32(WEBRTC_SPL_MUL_16_16(w16_maxSample, w16_maxSample)); |
| w16_tmp = WEBRTC_SPL_MAX(0, w16_tmp); |
| |
| WebRtcNetEQ_CrossCorr(pw32_autoCorr, pw16_vec, pw16_vec, w16_vecLen, BGN_LPC_ORDER + 1, |
| w16_tmp, -1); |
| |
| /* Copy back data */ |
| WEBRTC_SPL_MEMCPY_W16(pw16_vec - BGN_LPC_ORDER, pw16_tempVec, BGN_LPC_ORDER); |
| |
| w16_enSampleShift = 8 - w16_tmp; /* Number of shifts to get energy/sample */ |
| /* pw32_autoCorr[0]>>w16_enSampleShift */ |
| w32_en = WEBRTC_SPL_RSHIFT_W32(pw32_autoCorr[0], w16_enSampleShift); |
| if ((w32_en < BGN_Inst->w32_energyUpdate |
| #ifdef NETEQ_VAD |
| /* post-decode VAD disabled and w32_en sufficiently low */ |
| && !inst->VADInst.VADEnabled) |
| /* ... or, post-decode VAD says passive speaker */ |
| || (inst->VADInst.VADEnabled && inst->VADInst.VADDecision == 0) |
| #else |
| ) /* just close the extra parenthesis */ |
| #endif /* NETEQ_VAD */ |
| ) |
| { |
| /* Generate LPC coefficients */ |
| if (pw32_autoCorr[0] > 0) |
| { |
| /* regardless of whether the filter is actually updated or not, |
| update energy threshold levels, since we have in fact observed |
| a low energy signal */ |
| if (w32_en < BGN_Inst->w32_energyUpdate) |
| { |
| /* Never get under 1.0 in average sample energy */ |
| BGN_Inst->w32_energyUpdate = WEBRTC_SPL_MAX(w32_en, 1); |
| BGN_Inst->w32_energyUpdateLow = 0; |
| } |
| |
| stability = WebRtcSpl_LevinsonDurbin(pw32_autoCorr, pw16_A, pw16_rc, BGN_LPC_ORDER); |
| /* Only update BGN if filter is stable */ |
| if (stability != 1) |
| { |
| return; |
| } |
| } |
| else |
| { |
| /* Do not update */ |
| return; |
| } |
| /* Generate the CNG gain factor by looking at the energy of the residual */ |
| WebRtcSpl_FilterMAFastQ12(pw16_vec + w16_vecLen - 64, pw16_outVec, pw16_A, |
| BGN_LPC_ORDER + 1, 64); |
| w32_enBGN = WebRtcNetEQ_DotW16W16(pw16_outVec, pw16_outVec, 64, 0); |
| /* Dot product should never overflow since it is BGN and residual! */ |
| |
| /* |
| * Check spectral flatness |
| * Comparing the residual variance with the input signal variance tells |
| * if the spectrum is flat or not. |
| * (20*w32_enBGN) >= (w32_en<<6) |
| * Also ensure that the energy is non-zero. |
| */ |
| if ((WEBRTC_SPL_MUL_32_16(w32_enBGN, 20) >= WEBRTC_SPL_LSHIFT_W32(w32_en, 6)) |
| && (w32_en > 0)) |
| { |
| /* spectrum is flat enough; save filter parameters */ |
| |
| WEBRTC_SPL_MEMCPY_W16(BGN_Inst->pw16_filter, pw16_A, BGN_LPC_ORDER+1); |
| WEBRTC_SPL_MEMCPY_W16(BGN_Inst->pw16_filterState, |
| pw16_vec + w16_vecLen - BGN_LPC_ORDER, BGN_LPC_ORDER); |
| |
| /* Save energy level */ |
| BGN_Inst->w32_energy = WEBRTC_SPL_MAX(w32_en, 1); |
| |
| /* Update energy threshold levels */ |
| /* Never get under 1.0 in average sample energy */ |
| BGN_Inst->w32_energyUpdate = WEBRTC_SPL_MAX(w32_en, 1); |
| BGN_Inst->w32_energyUpdateLow = 0; |
| |
| /* Normalize w32_enBGN to 29 or 30 bits before sqrt */ |
| w16_tmp2 = WebRtcSpl_NormW32(w32_enBGN) - 1; |
| if (w16_tmp2 & 0x1) |
| { |
| w16_tmp2 -= 1; /* Even number of shifts required */ |
| } |
| w32_enBGN = WEBRTC_SPL_SHIFT_W32(w32_enBGN, w16_tmp2); |
| |
| /* Calculate scale and shift factor */ |
| BGN_Inst->w16_scale = (WebRtc_Word16) WebRtcSpl_SqrtFloor(w32_enBGN); |
| BGN_Inst->w16_scaleShift = 13 + ((6 + w16_tmp2) >> 1); /* RANDN table is in Q13, */ |
| /* 6=log2(64) */ |
| |
| BGN_Inst->w16_initialized = 1; |
| } |
| |
| } |
| else |
| { |
| /* |
| * Will only happen if post-decode VAD is disabled and w32_en is not low enough. |
| * Increase the threshold for update so that it increases by a factor 4 in four |
| * seconds. |
| * energy = energy * 1.0035 |
| */ |
| w32_tmp = WEBRTC_SPL_MUL_16_16_RSFT(NETEQFIX_BGNFRAQINCQ16, |
| BGN_Inst->w32_energyUpdateLow, 16); |
| w32_tmp += WEBRTC_SPL_MUL_16_16(NETEQFIX_BGNFRAQINCQ16, |
| (WebRtc_Word16)(BGN_Inst->w32_energyUpdate & 0xFF)); |
| w32_tmp += (WEBRTC_SPL_MUL_16_16(NETEQFIX_BGNFRAQINCQ16, |
| (WebRtc_Word16)((BGN_Inst->w32_energyUpdate>>8) & 0xFF)) << 8); |
| BGN_Inst->w32_energyUpdateLow += w32_tmp; |
| |
| BGN_Inst->w32_energyUpdate += WEBRTC_SPL_MUL_16_16(NETEQFIX_BGNFRAQINCQ16, |
| (WebRtc_Word16)(BGN_Inst->w32_energyUpdate>>16)); |
| BGN_Inst->w32_energyUpdate += BGN_Inst->w32_energyUpdateLow >> 16; |
| BGN_Inst->w32_energyUpdateLow = (BGN_Inst->w32_energyUpdateLow & 0x0FFFF); |
| |
| /* Update maximum energy */ |
| /* Decrease by a factor 1/1024 each time */ |
| BGN_Inst->w32_energyMax = BGN_Inst->w32_energyMax - (BGN_Inst->w32_energyMax >> 10); |
| if (w32_en > BGN_Inst->w32_energyMax) |
| { |
| BGN_Inst->w32_energyMax = w32_en; |
| } |
| |
| /* Set update level to at the minimum 60.21dB lower then the maximum energy */ |
| w32_enUpdateThreashold = (BGN_Inst->w32_energyMax + 524288) >> 20; |
| if (w32_enUpdateThreashold > BGN_Inst->w32_energyUpdate) |
| { |
| BGN_Inst->w32_energyUpdate = w32_enUpdateThreashold; |
| } |
| } |
| |
| #ifdef NETEQ_VAD |
| } /* closing initial if-statement */ |
| #endif /* NETEQ_VAD */ |
| |
| return; |
| } |
| |
| #undef SCRATCH_PW32_AUTO_CORR |
| #undef SCRATCH_PW16_TEMP_VEC |
| #undef SCRATCH_PW16_RC |
| #undef SCRATCH_PW16_OUT_VEC |
| |
