📄 exc_lbc.c
字号:
** Word16 *Src Fixed codebook excitation vector without train of Dirac
** Word16 Olp Closed-loop pitch lag of subframe 0 (for subframes 0 & 1)
** Closed-loop pitch lag of subframe 2 (for subframes 2 & 3)
**
** Outputs:
**
** Word16 *Dst excitation vector
**
** Return value: None
**
*/
void Gen_Trn( Word16 *Dst, Word16 *Src, Word16 Olp )
{
int i ;
Word16 Tmp0,Tmp1 ;
Word16 Tmp[SubFrLen] ;
Tmp0 = Olp ;
for ( i = 0 ; i < SubFrLen ; i ++ ) {
Tmp[i] = Src[i] ;
Dst[i] = Src[i] ;
}
while ( Tmp0 < SubFrLen ) {
for ( i = (int) Tmp0 ; i < SubFrLen ; i ++ ) {
Tmp1 = add( Dst[i], Tmp[i-(int)Tmp0] ) ;
Dst[i] = Tmp1 ;
}
Tmp0 = add( Tmp0, Olp ) ;
}
return;
}
/*
**
** Function: Find_Best()
**
** Description: Fixed codebook search for the high rate encoder.
** It performs the quantization of the residual signal.
** The excitation made of Np positive or negative pulses
** multiplied by a gain and whose positions on the grid are
** either all odd or all even, should approximate as best as
** possible the residual signal (perceptual criterion).
**
** Links to text: Section 2.15
**
** Arguments:
**
** BESTDEF *Best Parameters of the best excitation model
** Word16 *Tv Target vector
** Word16 *ImpResp Impulse response of the combined filter
** Word16 Np Number of pulses (6 for even subframes; 5 for odd subframes)
** Word16 Olp Closed-loop pitch lag of subframe 0 (for subframes 0 & 1)
** Closed-loop pitch lag of subframe 2 (for subframes 2 & 3)
**
** Outputs:
**
** BESTDEF *Best
**
** Return value: None
**
*/
void Find_Best( BESTDEF *Best, Word16 *Tv, Word16 *ImpResp, Word16 Np,
Word16 Olp )
{
int i,j,k,l ;
BESTDEF Temp ;
Word16 Exp ;
Word16 MaxAmpId ;
Word16 MaxAmp ;
Word32 Acc0,Acc1,Acc2 ;
Word16 Imr[SubFrLen] ;
Word16 OccPos[SubFrLen] ;
Word16 ImrCorr[SubFrLen] ;
Word32 ErrBlk[SubFrLen] ;
Word32 WrkBlk[SubFrLen] ;
/* Update Impulse response */
if ( Olp < (Word16) (SubFrLen-2) ) {
Temp.UseTrn = (Word16) 1 ;
Gen_Trn( Imr, ImpResp, Olp ) ;
}
else {
Temp.UseTrn = (Word16) 0 ;
for ( i = 0 ; i < SubFrLen ; i ++ )
Imr[i] = ImpResp[i] ;
}
/* Scale Imr to avoid overflow */
for ( i = 0 ; i < SubFrLen ; i ++ )
OccPos[i] = shr( Imr[i], (Word16) 1 ) ;
/* Compute Imr AutoCorr function */
Acc0 = (Word32) 0 ;
for ( i = 0 ; i < SubFrLen ; i ++ )
Acc0 = L_mac( Acc0, OccPos[i], OccPos[i] ) ;
Exp = norm_l( Acc0 ) ;
Acc0 = L_shl( Acc0, Exp ) ;
ImrCorr[0] = round( Acc0 ) ;
/* Compute all the other */
for ( i = 1 ; i < SubFrLen ; i ++ ) {
Acc0 = (Word32) 0 ;
for ( j = i ; j < SubFrLen ; j ++ )
Acc0 = L_mac( Acc0, OccPos[j], OccPos[j-i] ) ;
Acc0 = L_shl( Acc0, Exp ) ;
ImrCorr[i] = round( Acc0 ) ;
}
/* Cross correlation with the signal */
Exp = sub( Exp, 4 ) ;
for ( i = 0 ; i < SubFrLen ; i ++ ) {
Acc0 = (Word32) 0 ;
for ( j = i ; j < SubFrLen ; j ++ )
Acc0 = L_mac( Acc0, Tv[j], Imr[j-i] ) ;
ErrBlk[i] = L_shl( Acc0, Exp ) ;
}
/* Search for the best sequence */
for ( k = 0 ; k < Sgrid ; k ++ ) {
Temp.GridId = (Word16) k ;
/* Find maximum amplitude */
Acc1 = (Word32) 0 ;
for ( i = k ; i < SubFrLen ; i += Sgrid ) {
Acc0 = L_abs( ErrBlk[i] ) ;
if ( Acc0 >= Acc1 ) {
Acc1 = Acc0 ;
Temp.Ploc[0] = (Word16) i ;
}
}
/* Quantize the maximum amplitude */
Acc2 = Acc1 ;
Acc1 = (Word32) 0x40000000L ;
MaxAmpId = (Word16) (NumOfGainLev - MlqSteps) ;
for ( i = MaxAmpId ; i >= MlqSteps ; i -- ) {
Acc0 = L_mult( FcbkGainTable[i], ImrCorr[0] ) ;
Acc0 = L_sub( Acc0, Acc2 ) ;
Acc0 = L_abs( Acc0 ) ;
if ( Acc0 < Acc1 ) {
Acc1 = Acc0 ;
MaxAmpId = (Word16) i ;
}
}
MaxAmpId -- ;
for ( i = 1 ; i <=2*MlqSteps ; i ++ ) {
for ( j = k ; j < SubFrLen ; j += Sgrid ) {
WrkBlk[j] = ErrBlk[j] ;
OccPos[j] = (Word16) 0 ;
}
Temp.MampId = MaxAmpId - (Word16) MlqSteps + (Word16) i ;
MaxAmp = FcbkGainTable[Temp.MampId] ;
if ( WrkBlk[Temp.Ploc[0]] >= (Word32) 0 )
Temp.Pamp[0] = MaxAmp ;
else
Temp.Pamp[0] = negate(MaxAmp) ;
OccPos[Temp.Ploc[0]] = (Word16) 1 ;
for ( j = 1 ; j < Np ; j ++ ) {
Acc1 = (Word32) 0xc0000000L ;
for ( l = k ; l < SubFrLen ; l += Sgrid ) {
if ( OccPos[l] != (Word16) 0 )
continue ;
Acc0 = WrkBlk[l] ;
Acc0 = L_msu( Acc0, Temp.Pamp[j-1],
ImrCorr[abs_s((Word16)(l-Temp.Ploc[j-1]))] ) ;
WrkBlk[l] = Acc0 ;
Acc0 = L_abs( Acc0 ) ;
if ( Acc0 > Acc1 ) {
Acc1 = Acc0 ;
Temp.Ploc[j] = (Word16) l ;
}
}
if ( WrkBlk[Temp.Ploc[j]] >= (Word32) 0 )
Temp.Pamp[j] = MaxAmp ;
else
Temp.Pamp[j] = negate(MaxAmp) ;
OccPos[Temp.Ploc[j]] = (Word16) 1 ;
}
/* Compute error vector */
for ( j = 0 ; j < SubFrLen ; j ++ )
OccPos[j] = (Word16) 0 ;
for ( j = 0 ; j < Np ; j ++ )
OccPos[Temp.Ploc[j]] = Temp.Pamp[j] ;
for ( l = SubFrLen-1 ; l >= 0 ; l -- ) {
Acc0 = (Word32) 0 ;
for ( j = 0 ; j <= l ; j ++ )
Acc0 = L_mac( Acc0, OccPos[j], Imr[l-j] ) ;
Acc0 = L_shl( Acc0, (Word16) 2 ) ;
OccPos[l] = extract_h( Acc0 ) ;
}
/* Evaluate error */
Acc1 = (Word32) 0 ;
for ( j = 0 ; j < SubFrLen ; j ++ ) {
Acc1 = L_mac( Acc1, Tv[j], OccPos[j] ) ;
Acc0 = L_mult( OccPos[j], OccPos[j] ) ;
Acc1 = L_sub( Acc1, L_shr( Acc0, (Word16) 1 ) ) ;
}
if ( Acc1 > (*Best).MaxErr ) {
(*Best).MaxErr = Acc1 ;
(*Best).GridId = Temp.GridId ;
(*Best).MampId = Temp.MampId ;
(*Best).UseTrn = Temp.UseTrn ;
for ( j = 0 ; j < Np ; j ++ ) {
(*Best).Pamp[j] = Temp.Pamp[j] ;
(*Best).Ploc[j] = Temp.Ploc[j] ;
}
}
}
}
return;
}
/*
**
** Function: Fcbk_Pack()
**
** Description: Encoding of the pulse positions and gains for the high
** rate case.
** Combinatorial encoding is used to transmit the optimal
** combination of pulse locations.
**
** Links to text: Section 2.15
**
** Arguments:
**
** Word16 *Dpnt Excitation vector
** SFSDEF *Sfs Encoded parameters of the excitation model
** BESTDEF *Best Parameters of the best excitation model
** Word16 Np Number of pulses (6 for even subframes; 5 for odd subframes)
**
** Outputs:
**
** SFSDEF *Sfs Encoded parameters of the excitation model
**
** Return value: None
**
*/
void Fcbk_Pack( Word16 *Dpnt, SFSDEF *Sfs, BESTDEF *Best, Word16 Np )
{
int i,j ;
/* Code the amplitudes and positions */
j = MaxPulseNum - (int) Np ;
(*Sfs).Pamp = (Word16) 0 ;
(*Sfs).Ppos = (Word32) 0 ;
for ( i = 0 ; i < SubFrLen/Sgrid ; i ++ ) {
if ( Dpnt[(int)(*Best).GridId + Sgrid*i] == (Word16) 0 )
(*Sfs).Ppos = L_add( (*Sfs).Ppos, CombinatorialTable[j][i] ) ;
else {
(*Sfs).Pamp = shl( (*Sfs).Pamp, (Word16) 1 ) ;
if ( Dpnt[(int)(*Best).GridId + Sgrid*i] < (Word16) 0 )
(*Sfs).Pamp = add( (*Sfs).Pamp, (Word16) 1 ) ;
j ++ ;
/* Check for end */
if ( j == MaxPulseNum )
break ;
}
}
(*Sfs).Mamp = (*Best).MampId ;
(*Sfs).Grid = (*Best).GridId ;
(*Sfs).Tran = (*Best).UseTrn ;
return;
}
/*
**
** Function: Fcbk_Unpk()
**
** Description: Decoding of the fixed codebook excitation for both rates.
** Gains, pulse positions, grid position (odd or even), signs
** are decoded and used to reconstruct the excitation.
**
** Links to text: Section 2.17 & 3.5
**
** Arguments:
**
** Word16 *Tv Decoded excitation vector
** SFSDEF Sfs Encoded parameters of the excitation (for one subframe)
** Word16 Olp Closed loop adaptive pitch lag
** Word16 Sfc Subframe index
**
** Outputs:
**
** Word16 *Tv Decoded excitation vector
**
** Return value: None
**
*/
void Fcbk_Unpk( Word16 *Tv, SFSDEF Sfs, Word16 Olp, Word16 Sfc )
{
int i,j ;
Word32 Acc0 ;
Word16 Np ;
Word16 Tv_tmp[SubFrLen+4];
Word16 acelp_gain, acelp_sign, acelp_shift, acelp_pos;
Word16 offset, ipos, T0_acelp, gain_T0;
switch(WrkRate) {
case Rate63: {
Np = Nb_puls[(int)Sfc] ;
for ( i = 0 ; i < SubFrLen ; i ++ )
Tv[i] = (Word16) 0 ;
if ( Sfs.Ppos >= MaxPosTable[Sfc] )
return ;
/* Decode the amplitudes and positions */
j = MaxPulseNum - (int) Np ;
Acc0 = Sfs.Ppos ;
for ( i = 0 ; i < SubFrLen/Sgrid ; i ++ ) {
Acc0 = L_sub( Acc0, CombinatorialTable[j][i] ) ;
if ( Acc0 < (Word32) 0 ) {
Acc0 = L_add( Acc0, CombinatorialTable[j][i] ) ;
j ++ ;
if ( (Sfs.Pamp & (1 << (MaxPulseNum-j) )) != (Word16) 0 )
Tv[(int)Sfs.Grid + Sgrid*i] = -FcbkGainTable[Sfs.Mamp] ;
else
Tv[(int)Sfs.Grid + Sgrid*i] = FcbkGainTable[Sfs.Mamp] ;
if ( j == MaxPulseNum )
break ;
}
}
if ( Sfs.Tran == (Word16) 1 )
Gen_Trn( Tv, Tv, Olp ) ;
break;
}
case Rate53: {
for ( i = 0 ; i < SubFrLen+4 ; i ++ )
Tv_tmp[i] = (Word16) 0 ;
/* decoding gain */
acelp_gain = FcbkGainTable[Sfs.Mamp];
/* decoding grid */
acelp_shift = Sfs.Grid;
/* decoding Sign */
acelp_sign = Sfs.Pamp;
/* decoding Pos */
acelp_pos = (short) Sfs.Ppos;
offset = 0;
for(i=0; i<4; i++) {
ipos = (acelp_pos & (Word16)0x0007) ;
ipos = shl(ipos,3) + acelp_shift + offset;
if( (acelp_sign & 1 )== 1) {
Tv_tmp[ipos] = acelp_gain;
}
else {
Tv_tmp[ipos] = -acelp_gain;
}
offset = add(offset,2);
acelp_pos = shr(acelp_pos, 3);
acelp_sign = shr(acelp_sign,1);
}
for (i = 0; i < SubFrLen; i++) Tv[i] = Tv_tmp[i];
T0_acelp = search_T0( (Word16) (Olp-1+Sfs.AcLg), Sfs.AcGn,
&gain_T0);
if(T0_acelp <SubFrLen-2) {
/* code[i] += 0.8 * code[i-Olp] */
for (i = T0_acelp ; i < SubFrLen; i++)
Tv[i] = add(Tv[i], mult(Tv[i-T0_acelp ], gain_T0));
}
break;
}
}
return;
}
/*
**
** Function: Find_Acbk()
**
** Description: Computation of adaptive codebook contribution in
** closed-loop around the open-loop pitch lag (subframes 0 & 2)
** around the previous subframe closed-loop pitch lag
** (subframes 1 & 3). For subframes 0 & 2, the pitch lag is
** encoded whereas for subframes 1 & 3, only the difference
** with the previous value is encoded (-1, 0, +1 or +2).
** The pitch predictor gains are quantized using one of the two
** codebooks (85 entries or 170 entries) depending on the
** rate and on the pitch lag value.
** Finally, the contribution of the pitch predictor is decoded
** and subtracted to obtain the residual signal.
**
** Links to text: Section 2.14
**
** Arguments:
**
** Word16 *Tv Target vector
** Word16 *ImpResp Impulse response of the combined filter
** Word16 *PrevExc Previous excitation vector
** LINEDEF *Line Contains pitch related parameters (open/closed loop lag, gain)
** Word16 Sfc Subframe index
**
** Outputs:
**
** Word16 *Tv Residual vector
** LINEDEF *Line Contains pitch related parameters (closed loop lag, gain)
**
** Return value: None
**
*/
void Find_Acbk( Word16 *Tv, Word16 *ImpResp, Word16 *PrevExc, LINEDEF
*Line, Word16 Sfc )
{
int i,j,k,l ;
Word32 Acc0,Acc1 ;
Word16 RezBuf[SubFrLen+ClPitchOrd-1] ;
Word16 FltBuf[ClPitchOrd][SubFrLen] ;
Word32 CorBuf[4*(2*ClPitchOrd + ClPitchOrd*(ClPitchOrd-1)/2)] ;
Word32 *lPnt ;
Word16 CorVct[4*(2*ClPitchOrd + ClPitchOrd*(ClPitchOrd-1)/2)] ;
Word16 *sPnt ;
Word16 Olp ;
Word16 Lid ;
Word16 Gid ;
Word16 Hb ;
Word16 Exp ;
Word16 Bound[2] ;
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -