📄 g7231_lsp.c
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* constant component removed.
*/
for ( j = 0 ; j < G7231BandInfoTable[k][1] ; j ++ )
Tmp[j] = G7231mult_r( Wvect[G7231BandInfoTable[k][0]+j],
LspQntPnt[j] ) ;
Acc0 = (Word32) 0 ;
for ( j = 0 ; j < G7231BandInfoTable[k][1] ; j ++ )
Acc0 = G7231L_mac( Acc0, Tv[G7231BandInfoTable[k][0]+j], Tmp[j] ) ;
Acc0 = G7231L_shl( Acc0, (Word16) 1 ) ;
for ( j = 0 ; j < G7231BandInfoTable[k][1] ; j ++ )
Acc0 = G7231L_msu( Acc0, LspQntPnt[j], Tmp[j] ) ;
LspQntPnt += G7231BandInfoTable[k][1] ;
/*
* Compare the metric to the previous maximum and select the
* new index
*/
if ( Acc0 > Acc1 ) {
Acc1 = Acc0 ;
Indx = (Word32) i ;
}
}
/*
* Pack the result with the optimum index for this band
*/
Rez = G7231L_shl( Rez, (Word16) G7231LspCbBits ) ;
Rez = G7231L_add( Rez, Indx ) ;
}
return Rez ;
}
void G7231Lsp_Inq( Word16 *Lsp, Word16 *PrevLsp, Word32 LspId, Word16 Crc )
{
int i,j ;
Word16 *LspQntPnt ;
Word16 Scon ;
Word16 Lprd ;
Word16 Tmp ;
Flag Test ;
/*
* Check for frame erasure. If a frame erasure has occurred, the
* resulting VQ table entries are zero. In addition, a different
* fixed predictor and minimum frequency separation are used.
*/
if ( Crc == (Word16) 0 ) {
Scon = (Word16) 0x0100 ;
Lprd = G7231LspPrd0 ;
}
else {
LspId = (Word32) 0 ;
Scon = (Word16) 0x0200 ;
Lprd = G7231LspPrd1 ;
}
/*
* Inverse quantize the 10th-order LSP vector. Each band is done
* separately.
*/
for ( i = G7231LspQntBands-1; i >= 0 ; i -- ) {
/*
* Get the VQ table entry corresponding to the transmitted index
*/
Tmp = (Word16) ( LspId & (Word32) 0x000000ff ) ;
LspId >>= 8 ;
LspQntPnt = G7231BandQntTable[i] ;
for ( j = 0 ; j < G7231BandInfoTable[i][1] ; j ++ )
Lsp[G7231BandInfoTable[i][0] + j] =
LspQntPnt[Tmp*G7231BandInfoTable[i][1] + j] ;
}
/*
* Subtract the DC component from the previous frame's quantized
* vector
*/
for ( j = 0 ; j < G7231LpcOrder ; j ++ )
PrevLsp[j] = G7231sub(PrevLsp[j], G7231LspDcTable[j] ) ;
/*
* Generate the prediction vector using a fixed first-order
* predictor based on the previous frame's (DC-free) quantized
* vector
*/
for ( j = 0 ; j < G7231LpcOrder ; j ++ ) {
Tmp = G7231mult_r( PrevLsp[j], Lprd ) ;
Lsp[j] = G7231add( Lsp[j], Tmp ) ;
}
/*
* Add the DC component back to the previous quantized vector,
* which is needed in later routines
*/
for ( j = 0 ; j < G7231LpcOrder ; j ++ ) {
PrevLsp[j] = G7231add( PrevLsp[j], G7231LspDcTable[j] ) ;
Lsp[j] = G7231add( Lsp[j], G7231LspDcTable[j] ) ;
}
/*
* Perform a stability test on the quantized LSP frequencies. This
* test checks that the frequencies are ordered, with a minimum
* separation between each. If the test fails, the frequencies are
* iteratively modified until the test passes. If after 10
* iterations the test has not passed, the previous frame's
* quantized LSP vector is used.
*/
for ( i = 0 ; i < G7231LpcOrder ; i ++ ) {
/* Check the first frequency */
if ( Lsp[0] < (Word16) 0x180 )
Lsp[0] = (Word16) 0x180 ;
/* Check the last frequency */
if ( Lsp[G7231LpcOrder-1] > (Word16) 0x7e00 )
Lsp[G7231LpcOrder-1] = (Word16) 0x7e00 ;
/* Perform the modification */
for ( j = 1 ; j < G7231LpcOrder ; j ++ ) {
Tmp = G7231add( Scon, Lsp[j-1] ) ;
Tmp = G7231sub( Tmp, Lsp[j] ) ;
if ( Tmp > (Word16) 0 ) {
Tmp = G7231shr( Tmp, (Word16) 1 ) ;
Lsp[j-1] = G7231sub( Lsp[j-1], Tmp ) ;
Lsp[j] = G7231add( Lsp[j], Tmp ) ;
}
}
Test = False ;
/*
* Test the modified frequencies for stability. Break out of
* the loop if the frequencies are stable.
*/
for ( j = 1 ; j < G7231LpcOrder ; j ++ ) {
Tmp = G7231add( Lsp[j-1], Scon ) ;
Tmp = G7231sub( Tmp, (Word16) 4 ) ;
Tmp = G7231sub( Tmp, Lsp[j] ) ;
if ( Tmp > (Word16) 0 )
Test = True ;
}
if ( Test == False )
break ;
}
/*
* Return the result of the stability check. True = not stable,
* False = stable.
*/
if ( Test == True) {
for ( j = 0 ; j < G7231LpcOrder ; j ++ )
Lsp[j] = PrevLsp[j] ;
}
return;
}
void G7231Lsp_Int( Word16 *QntLpc, Word16 *CurrLsp, Word16 *PrevLsp )
{
int i,j ;
Word16 Tmp ;
Word16 *Dpnt ;
Word32 Acc0 ;
/*
* Initialize the interpolation factor
*/
Tmp = (Word16) (G7231MIN_16 / G7231SubFrames ) ;
Dpnt = QntLpc ;
/*
* Do for all subframes
*/
for ( i = 0 ; i < G7231SubFrames ; i ++ ) {
/*
* Compute the quantized LSP frequencies by linear interpolation
* of the frequencies from subframe 3 of the current and
* previous frames
*/
for ( j = 0 ; j < G7231LpcOrder ; j ++ ) {
Acc0 = G7231L_deposit_h( PrevLsp[j] ) ;
Acc0 = G7231L_mac( Acc0, Tmp, PrevLsp[j] ) ;
Acc0 = G7231L_msu( Acc0, Tmp, CurrLsp[j] ) ;
Dpnt[j] = G7231round( Acc0 ) ;
}
/*
* Convert the quantized LSP frequencies to quantized LPC
* coefficients
*/
G7231LsptoA( Dpnt ) ;
Dpnt += G7231LpcOrder ;
/* Update the interpolation factor */
Tmp = G7231add( Tmp, (Word16) (G7231MIN_16 / G7231SubFrames ) ) ;
}
}
void G7231LsptoA( Word16 *Lsp )
{
int i,j ;
Word32 Acc0,Acc1 ;
Word16 Tmp ;
Word32 P[G7231LpcOrder/2+1] ;
Word32 Q[G7231LpcOrder/2+1] ;
/*
* Compute the cosines of the LSP frequencies by table lookup and
* linear interpolation
*/
for ( i = 0 ; i < G7231LpcOrder ; i ++ ) {
/*
* Do the table lookup using bits [15:7] of the LSP frequency
*/
j = (int) G7231shr( Lsp[i], (Word16) 7 ) ;
Acc0 = G7231L_deposit_h( G7231CosineTable[j] ) ;
Tmp = G7231sub(G7231CosineTable[j+1], G7231CosineTable[j] ) ;
Acc0 = G7231L_mac( Acc0, Tmp, G7231add( G7231shl( (Word16)(Lsp[i] & 0x007f) ,
(Word16)8 ), (Word16) 0x0080 ) ) ;
Acc0 = G7231L_shl( Acc0, (Word16) 1 ) ;
Lsp[i] = G7231negate( G7231round( Acc0 ) ) ;
}
P[0] = (Word32) 0x10000000L ;
P[1] = G7231L_mult( Lsp[0], (Word16) 0x2000 ) ;
P[1] = G7231L_mac( P[1], Lsp[2], (Word16) 0x2000 ) ;
P[2] = G7231L_mult( Lsp[0], Lsp[2] ) ;
P[2] = G7231L_shr( P[2], (Word16) 1 ) ;
P[2] = G7231L_add( P[2], (Word32) 0x20000000L ) ;
Q[0] = (Word32) 0x10000000L ;
Q[1] = G7231L_mult( Lsp[1], (Word16) 0x2000 ) ;
Q[1] = G7231L_mac( Q[1], Lsp[3], (Word16) 0x2000 ) ;
Q[2] = G7231L_mult( Lsp[1], Lsp[3] ) ;
Q[2] = G7231L_shr( Q[2], (Word16) 1 ) ;
Q[2] = G7231L_add( Q[2], (Word32) 0x20000000L ) ;
for ( i = 2 ; i < G7231LpcOrder/2 ; i ++ ) {
/* Compute coefficient (i+1) */
Acc0 = P[i] ;
Acc0 = G7231L_mls( Acc0, Lsp[2*i+0] ) ;
Acc0 = G7231L_add( Acc0, P[i-1] ) ;
P[i+1] = Acc0 ;
Acc1 = Q[i] ;
Acc1 = G7231L_mls( Acc1, Lsp[2*i+1] ) ;
Acc1 = G7231L_add( Acc1, Q[i-1] ) ;
Q[i+1] = Acc1 ;
/* Compute coefficients i, i-1, ..., 2 */
for ( j = i ; j >= 2 ; j -- ) {
Acc0 = P[j-1] ;
Acc0 = G7231L_mls( Acc0, Lsp[2*i+0] ) ;
Acc0 = G7231L_add( Acc0, G7231L_shr(P[j], (Word16) 1 ) ) ;
Acc0 = G7231L_add( Acc0, G7231L_shr(P[j-2], (Word16) 1 ) ) ;
P[j] = Acc0 ;
Acc1 = Q[j-1] ;
Acc1 = G7231L_mls( Acc1, Lsp[2*i+1] ) ;
Acc1 = G7231L_add( Acc1, G7231L_shr(Q[j], (Word16) 1 ) ) ;
Acc1 = G7231L_add( Acc1, G7231L_shr(Q[j-2], (Word16) 1 ) ) ;
Q[j] = Acc1 ;
}
/* Compute coefficients 1, 0 */
P[0] = G7231L_shr( P[0], (Word16) 1 ) ;
Q[0] = G7231L_shr( Q[0], (Word16) 1 ) ;
Acc0 = G7231L_deposit_h( Lsp[2*i+0] ) ;
Acc0 = G7231L_shr( Acc0, (Word16) i ) ;
Acc0 = G7231L_add( Acc0, P[1] ) ;
Acc0 = G7231L_shr( Acc0, (Word16) 1 ) ;
P[1] = Acc0 ;
Acc1 = G7231L_deposit_h( Lsp[2*i+1] ) ;
Acc1 = G7231L_shr( Acc1, (Word16) i ) ;
Acc1 = G7231L_add( Acc1, Q[1] ) ;
Acc1 = G7231L_shr( Acc1, (Word16) 1 ) ;
Q[1] = Acc1 ;
}
for ( i = 0 ; i < G7231LpcOrder/2 ; i ++ ) {
Acc0 = P[i] ;
Acc0 = G7231L_add( Acc0, P[i+1] ) ;
Acc0 = G7231L_sub( Acc0, Q[i] ) ;
Acc0 = G7231L_add( Acc0, Q[i+1] ) ;
Acc0 = G7231L_shl( Acc0, (Word16) 3 ) ;
Lsp[i] = G7231negate( G7231round( Acc0 ) ) ;
Acc1 = P[i] ;
Acc1 = G7231L_add( Acc1, P[i+1] ) ;
Acc1 = G7231L_add( Acc1, Q[i] ) ;
Acc1 = G7231L_sub( Acc1, Q[i+1] ) ;
Acc1 = G7231L_shl( Acc1, (Word16) 3 ) ;
Lsp[G7231LpcOrder-1-i] = G7231negate( G7231round( Acc1 ) ) ;
}
}
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