ref: 991c0f0254426e67f2f7938876001acca31cb5dd
dir: /libcelt/bands.c/
/* (C) 2007 Jean-Marc Valin, CSIRO
*/
/*
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modification, are permitted provided that the following conditions
are met:
- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
- Neither the name of the Xiph.org Foundation nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <math.h>
#include "bands.h"
const int qbank[NBANDS+2] = {0, 2, 4, 6, 8, 12, 16, 20, 24, 28, 36, 44, 52, 68, 84, 116, 128};
/* Compute the energy in each of the bands */
void compute_bands(float *X, int B, float *bank)
{
int i;
for (i=0;i<NBANDS;i++)
{
int j;
bank[i] = 1e-10;
for (j=B*qbank[i];j<B*qbank[i+1];j++)
bank[i] += X[j]*X[j];
bank[i] = sqrt(bank[i]);
}
}
/* Normalise each band such that the energy is one. */
void normalise_bands(float *X, int B, float *bank)
{
int i;
for (i=0;i<NBANDS;i++)
{
int j;
float x = 1.f/bank[i];
for (j=B*qbank[i];j<B*qbank[i+1];j++)
X[j] *= x;
}
for (i=B*qbank[NBANDS];i<B*qbank[NBANDS+1];i++)
X[i] = 0;
}
/* De-normalise the energy to produce the synthesis from the unit-energy bands */
void denormalise_bands(float *X, int B, float *bank)
{
int i;
for (i=0;i<NBANDS;i++)
{
int j;
float x = bank[i];
for (j=B*qbank[i];j<B*qbank[i+1];j++)
X[j] *= x;
}
for (i=B*qbank[NBANDS];i<B*qbank[NBANDS+1];i++)
X[i] = 0;
}
/* Scales the pulse-codebook entry in each band such that unit-energy is conserved when
adding the pitch */
void pitch_renormalise_bands(float *X, int B, float *P)
{
int i;
for (i=0;i<NBANDS;i++)
{
int j;
float Rpp=0;
float Rxp=0;
float Rxx=0;
float gain1;
for (j=B*qbank[i];j<B*qbank[i+1];j++)
{
Rxp += X[j]*P[j];
Rpp += P[j]*P[j];
Rxx += X[j]*X[j];
}
float arg = Rxp*Rxp + 1 - Rpp;
gain1 = sqrt(arg)-Rxp;
if (Rpp>.9999)
Rpp = .9999;
Rxx = 0;
for (j=B*qbank[i];j<B*qbank[i+1];j++)
{
X[j*2-1] = P[j]+gain1*X[j];
Rxx += X[j]*X[j];
}
}
for (i=B*qbank[NBANDS];i<B*qbank[NBANDS+1];i++)
X[i] = 0;
}