Code for computing band energies and normalising: adapted from CEFT.

1 files changed, 115 insertions, 0 deletions

diff --git a/libcelt/bands.c b/libcelt/bands.c
new file mode 100644
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+++ b/libcelt/bands.c
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+/* (C) 2007 Jean-Marc Valin, CSIRO
+*/
+/*
+   Redistribution and use in source and binary forms, with or without
+   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;
+}
+