void WebRtcIlbcfix_CreateAugmentedVec(
WebRtc_Word16 index, /* (i) Index for the augmented vector to be created */
WebRtc_Word16 *buffer, /* (i) Pointer to the end of the codebook memory that
is used for creation of the augmented codebook */
WebRtc_Word16 *cbVec /* (o) The construced codebook vector */
) {
WebRtc_Word16 ilow;
WebRtc_Word16 *ppo, *ppi;
WebRtc_Word16 cbVecTmp[4];
ilow = index-4;
/* copy the first noninterpolated part */
ppo = buffer-index;
WEBRTC_SPL_MEMCPY_W16(cbVec, ppo, index);
/* interpolation */
ppo = buffer - 4;
ppi = buffer - index - 4;
/* perform cbVec[ilow+k] = ((ppi[k]*alphaTbl[k])>>15) + ((ppo[k]*alphaTbl[3-k])>>15);
for k = 0..3
*/
WebRtcSpl_ElementwiseVectorMult(&cbVec[ilow], ppi, WebRtcIlbcfix_kAlpha, 4, 15);
WebRtcSpl_ReverseOrderMultArrayElements(cbVecTmp, ppo, &WebRtcIlbcfix_kAlpha[3], 4, 15);
WebRtcSpl_AddVectorsAndShift(&cbVec[ilow], &cbVec[ilow], cbVecTmp, 4, 0);
/* copy the second noninterpolated part */
ppo = buffer - index;
WEBRTC_SPL_MEMCPY_W16(cbVec+index,ppo,(SUBL-index));
}
void WebRtcIlbcfix_CreateAugmentedVec(
size_t index, /* (i) Index for the augmented vector to be
created */
const int16_t* buffer, /* (i) Pointer to the end of the codebook memory
that is used for creation of the augmented
codebook */
int16_t* cbVec) { /* (o) The constructed codebook vector */
size_t ilow;
const int16_t *ppo, *ppi;
int16_t cbVecTmp[4];
/* Interpolation starts 4 elements before cbVec+index, but must not start
outside |cbVec|; clamping interp_len to stay within |cbVec|.
*/
size_t interp_len = WEBRTC_SPL_MIN(index, 4);
ilow = index - interp_len;
/* copy the first noninterpolated part */
ppo = buffer-index;
WEBRTC_SPL_MEMCPY_W16(cbVec, ppo, index);
/* interpolation */
ppo = buffer - interp_len;
ppi = buffer - index - interp_len;
/* perform cbVec[ilow+k] = ((ppi[k]*alphaTbl[k])>>15) +
((ppo[k]*alphaTbl[interp_len-1-k])>>15);
for k = 0..interp_len-1
*/
WebRtcSpl_ElementwiseVectorMult(&cbVec[ilow], ppi, WebRtcIlbcfix_kAlpha,
interp_len, 15);
WebRtcSpl_ReverseOrderMultArrayElements(
cbVecTmp, ppo, &WebRtcIlbcfix_kAlpha[interp_len - 1], interp_len, 15);
WebRtcSpl_AddVectorsAndShift(&cbVec[ilow], &cbVec[ilow], cbVecTmp, interp_len,
0);
/* copy the second noninterpolated part */
ppo = buffer - index;
/* |tempbuff2| is declared in WebRtcIlbcfix_GetCbVec and is SUBL+5 elements
long. |buffer| points one element past the end of that vector, i.e., at
tempbuff2+SUBL+5. Since ppo=buffer-index, we cannot read any more than
|index| elements from |ppo|.
|cbVec| is declared to be SUBL elements long in WebRtcIlbcfix_CbConstruct.
Therefore, we can only write SUBL-index elements to cbVec+index.
These two conditions limit the number of elements to copy.
*/
WEBRTC_SPL_MEMCPY_W16(cbVec+index, ppo, WEBRTC_SPL_MIN(SUBL-index, index));
}
void WebRtcIlbcfix_SimpleLpcAnalysis(
WebRtc_Word16 *lsf, /* (o) lsf coefficients */
WebRtc_Word16 *data, /* (i) new block of speech */
iLBC_Enc_Inst_t *iLBCenc_inst
/* (i/o) the encoder state structure */
) {
int k;
int scale;
WebRtc_Word16 is;
WebRtc_Word16 stability;
/* Stack based */
WebRtc_Word16 A[LPC_FILTERORDER + 1];
WebRtc_Word32 R[LPC_FILTERORDER + 1];
WebRtc_Word16 windowedData[BLOCKL_MAX];
WebRtc_Word16 rc[LPC_FILTERORDER];
is=LPC_LOOKBACK+BLOCKL_MAX-iLBCenc_inst->blockl;
WEBRTC_SPL_MEMCPY_W16(iLBCenc_inst->lpc_buffer+is,data,iLBCenc_inst->blockl);
/* No lookahead, last window is asymmetric */
for (k = 0; k < iLBCenc_inst->lpc_n; k++) {
is = LPC_LOOKBACK;
if (k < (iLBCenc_inst->lpc_n - 1)) {
/* Hanning table WebRtcIlbcfix_kLpcWin[] is in Q15-domain so the output is right-shifted 15 */
WebRtcSpl_ElementwiseVectorMult(windowedData, iLBCenc_inst->lpc_buffer, WebRtcIlbcfix_kLpcWin, BLOCKL_MAX, 15);
} else {
/* Hanning table WebRtcIlbcfix_kLpcAsymWin[] is in Q15-domain so the output is right-shifted 15 */
WebRtcSpl_ElementwiseVectorMult(windowedData, iLBCenc_inst->lpc_buffer+is, WebRtcIlbcfix_kLpcAsymWin, BLOCKL_MAX, 15);
}
/* Compute autocorrelation */
WebRtcSpl_AutoCorrelation(windowedData, BLOCKL_MAX, LPC_FILTERORDER, R, &scale);
/* Window autocorrelation vector */
WebRtcIlbcfix_Window32W32(R, R, WebRtcIlbcfix_kLpcLagWin, LPC_FILTERORDER + 1 );
/* Calculate the A coefficients from the Autocorrelation using Levinson Durbin algorithm */
stability=WebRtcSpl_LevinsonDurbin(R, A, rc, LPC_FILTERORDER);
/*
Set the filter to {1.0, 0.0, 0.0,...} if filter from Levinson Durbin algorithm is unstable
This should basically never happen...
*/
if (stability!=1) {
A[0]=4096;
WebRtcSpl_MemSetW16(&A[1], 0, LPC_FILTERORDER);
}
/* Bandwidth expand the filter coefficients */
WebRtcIlbcfix_BwExpand(A, A, (WebRtc_Word16*)WebRtcIlbcfix_kLpcChirpSyntDenum, LPC_FILTERORDER+1);
/* Convert from A to LSF representation */
WebRtcIlbcfix_Poly2Lsf(lsf + k*LPC_FILTERORDER, A);
}
is=LPC_LOOKBACK+BLOCKL_MAX-iLBCenc_inst->blockl;
WEBRTC_SPL_MEMCPY_W16(iLBCenc_inst->lpc_buffer,
iLBCenc_inst->lpc_buffer+LPC_LOOKBACK+BLOCKL_MAX-is, is);
return;
}
