/*
*
* \brief Perform complex-valued inverse modulation of the subband
* samples stored in rSubband (real part) and iSubband (imaginary
* part) and stores the result in timeOut
*
*/
static void
inverseModulation (float *qmfReal,
float *qmfImag,
HANDLE_SBR_QMF_FILTER_BANK synQmf
)
{
int i, no_synthesis_channels, M;
float r1, i1, r2, i2;
COUNT_sub_start("inverseModulation");
INDIRECT(1); MOVE(1);
no_synthesis_channels = synQmf->no_channels;
MULT(1);
M = no_synthesis_channels / 2;
PTR_INIT(2); /* pointer for qmfReal[],
qmfImag[] */
INDIRECT(1); LOOP(1);
for (i = synQmf->usb; i < no_synthesis_channels; i++) {
MOVE(2);
qmfReal[i]=qmfImag[i]=0;
}
FUNC(2);
cosMod (qmfReal, synQmf);
FUNC(2);
sinMod (qmfImag, synQmf);
PTR_INIT(4); /* pointer for qmfReal[],
qmfImag[],
qmfImag[no_synthesis_channels - 1 - i],
qmfReal[no_synthesis_channels - i - 1] */
LOOP(1);
for (i = 0; i < M; i++) {
MOVE(4);
r1 = qmfReal[i];
i2 = qmfImag[no_synthesis_channels - 1 - i];
r2 = qmfReal[no_synthesis_channels - i - 1];
i1 = qmfImag[i];
ADD(4); STORE(4);
qmfReal[i] = (r1 - i1);
qmfImag[no_synthesis_channels - 1 - i] = -(r1 + i1);
qmfReal[no_synthesis_channels - i - 1] = (r2 - i2);
qmfImag[i] = -(r2 + i2);
}
COUNT_sub_end();
}
/*
*
* \brief Perform complex-valued forward modulation of the time domain
* data of timeIn and stores the real part of the subband
* samples in rSubband, and the imaginary part in iSubband
*
*/
static void
sbrForwardModulation (const float *timeIn,
float *rSubband,
float *iSubband,
HANDLE_SBR_QMF_FILTER_BANK anaQmf
)
{
int i, offset;
float real, imag;
COUNT_sub_start("sbrForwardModulation");
MOVE(1);
offset = 2 * NO_ANALYSIS_CHANNELS;
PTR_INIT(1); /* pointer for timeIn[offset - 1 - i] */
LOOP(1);
for (i = 0; i < NO_ANALYSIS_CHANNELS; i++) {
ADD(2); STORE(2);
rSubband[i] = timeIn[i] - timeIn[offset - 1 - i];
iSubband[i] = timeIn[i] + timeIn[offset - 1 - i];
}
FUNC(2);
cosMod (rSubband, anaQmf);
FUNC(2);
sinMod (iSubband, anaQmf);
PTR_INIT(4); /* pointers for rSubband[i],
iSubband[i],
anaQmf->t_cos[i],
anaQmf->t_sin[i] */
INDIRECT(1); LOOP(1);
for (i = 0; i < anaQmf->lsb; i++) {
MOVE(2);
real = rSubband[i];
imag = iSubband[i];
MULT(1); MAC(1); STORE(1);
rSubband[i] = real * anaQmf->t_cos[i] + imag * anaQmf->t_sin[i];
MULT(2); ADD(1); STORE(1);
iSubband[i] = imag * anaQmf->t_cos[i] - real * anaQmf->t_sin[i];
}
COUNT_sub_end();
}
/*******************************************************************************
Functionname: inverseModulation
*******************************************************************************
Description: Performs inverse modulation.
Return: none
*******************************************************************************/
static void
inverseModulation (const float *sbrReal,
const float *sbrImag,
float *timeOut,
HANDLE_SBR_QMF_FILTER_BANK qmfBank)
{
int i;
float gain = 0.015625f;
float r1, i1, r2, i2;
/* counting previous operations */
/* timeOut[i]
timeOut[32 + i]
sbrReal[i]
sbrImag[i]
*/
for (i = 0; i < 32; i++) {
timeOut[i] = gain * sbrReal[i];
timeOut[32 + i] = gain * sbrImag[i];
}
cosMod (timeOut, qmfBank);
sinMod (timeOut + 32, qmfBank);
/* timeOut[i]
timeOut[63 - i]
timeOut[31 - i]
timeOut[32 + i]
*/
for (i = 0; i < 16; i++) {
r1 = timeOut[i];
i2 = timeOut[63 - i];
r2 = timeOut[31 - i];
i1 = timeOut[32 + i];
timeOut[i] = r1 - i1;
timeOut[63 - i] = -(r1 + i1);
timeOut[31 - i] = r2 - i2;
timeOut[32 + i] = -(r2 + i2);
}
}
