Implementing a 3-tap long-term predictor. Also changed frame size to 160

git-svn-id: http://svn.xiph.org/trunk/speex@3059 0101bb08-14d6-0310-b084-bc0e0c8e3800

3 files changed, 77 insertions, 7 deletions

diff --git a/libspeex/ltp.c b/libspeex/ltp.c
index 8eec360..6ffa174 100644
--- a/libspeex/ltp.c
+++ b/libspeex/ltp.c
@@ -3,6 +3,11 @@
    Lont-Term Prediction functions
 */
 
+
+/*static float lp4[] = {0.00139, 0.00853, 0.01465, -0.00000, -0.04766, -0.10610, -0.11333, 0.00000, 0.25616, 0.59397, 0.88498, 1.00000, 0.88498, 0.59397, 0.25616,  0.00000, -0.11333, -0.10610, -0.04766, -0.00000, 0.01465, 0.00853, 0.00139};
+ */
+
+
 /* Computes the open-loop pitch prediction. Returns pitch period and pitch gain */
 int open_loop_ltp(float *x, int len, int start, int end, float *gain)
    /*  x:     time-domain signal (note, x[-end] must be valid)
@@ -30,6 +35,67 @@ int open_loop_ltp(float *x, int len, int start, int end, float *gain)
          best_period=period;
          *gain = corr/(energy+1);
       }
+      
    }
    return best_period;
 }
+
+
+int three_tap_ltp(float *x, int len, int start, int end, float *gain)
+
+   /*  x:     time-domain signal (note, x[-end] must be valid)
+       len:   length of the x signal
+       start: smallest pitch period possible
+       end:   largest pitch period possible
+       gain:  return value for the pitch predictor gain
+    */
+{
+   int i, period, best_period=0;
+   float total, score[3]={0,0,0}, best_score=-1, corr[3]={0,0,0}, energy[3]={0,0,0};
+   float best_energy[3], best_corr[3];
+   float A[3][3];
+   for (period = start; period <= end; period++)
+   {
+      corr[0]=energy[0]=0;
+      for (i=0;i<len;i++)
+      {
+         corr[0] += x[i]*x[i-period];
+         energy[0] += x[i-period]*x[i-period];
+      }
+      score[0] = corr[0]*corr[0]/(energy[0]+1);
+      total = score[0]+2*score[1]+score[2];
+      if (total > best_score && period >= start+3 && period <= end-3)
+      {
+         best_score=total;
+         best_period=period;
+         for (i=0;i<3;i++)
+         {
+            best_corr[i]=corr[i];
+            best_energy[i]=energy[i];
+         }
+         *gain = corr[1]/(energy[1]+1);
+      }
+      corr[2]=corr[1];
+      corr[1]=corr[0];
+      energy[2]=energy[1];
+      energy[1]=energy[0];
+   }
+   A[0][0]=energy[0];
+   A[1][1]=energy[1];
+   A[2][2]=energy[2];
+   A[0][1]=0;
+   A[0][2]=0;
+   for (i=0;i<len;i++)
+   {
+      A[0][1] += x[i-best_period]*x[i-best_period-1];
+      A[0][2] += x[i-best_period]*x[i-best_period-2];
+   }
+   A[1][0]=A[0][1];
+   A[2][0]=A[0][2];
+   A[1][2]=A[0][1] - x[-best_period]*x[-best_period-1] 
+                   + x[len-best_period]*x[len-best_period-1];
+   A[2][1]=A[1][2];
+   return best_period-1;
+}
+
+
diff --git a/libspeex/speex.c b/libspeex/speex.c
index be9d79b..8f6f340 100644
--- a/libspeex/speex.c
+++ b/libspeex/speex.c
@@ -16,12 +16,12 @@
 void encoder_init(EncState *st)
 {
    int i;
-   st->frameSize = 128;
-   st->windowSize = 256;
+   st->frameSize = 160;
+   st->windowSize = 320;
    st->nbSubframes=4;
-   st->subframeSize=32;
+   st->subframeSize=40;
    st->lpcSize = 10;
-   st->bufSize = 512;
+   st->bufSize = 640;
    st->gamma=.9;
    st->inBuf = malloc(st->bufSize*sizeof(float));
    st->frame = st->inBuf + st->bufSize - st->windowSize;
@@ -108,6 +108,8 @@ void encode(EncState *st, float *in, int *outSize, void *bits)
       fprintf (stderr, "roots!=st->lpcSize\n");
       exit(1);
    }
+   for (i=0;i<st->lpcSize;i++)
+      st->lsp[i] = acos(st->lsp[i]);
    /*for (i=0;i<roots;i++)
       printf("%f ", st->lsp[i]);
       printf ("\n\n");*/
@@ -126,12 +128,14 @@ void encode(EncState *st, float *in, int *outSize, void *bits)
          st->interp_lsp[i] = (1-tmp)*st->old_lsp[i] + tmp*st->lsp[i];
 
       /* Compute interpolated LPCs */
+      for (i=0;i<st->lpcSize;i++)
+         st->interp_lsp[i] = cos(st->interp_lsp[i]);
       lsp_to_lpc(st->interp_lsp, st->interp_lpc, st->lpcSize);
 
-      /*for (i=0;i<st->lpcSize+1;i++)
+      for (i=0;i<st->lpcSize+1;i++)
          printf("%f ", st->interp_lpc[i]);
       printf ("\n");
-      */
+      
 
       /* Compute bandwidth-expanded LPCs for perceptual weighting*/
       tmp=1;
diff --git a/libspeex/testenc.c b/libspeex/testenc.c
index 6a4c188..52d1a45 100644
--- a/libspeex/testenc.c
+++ b/libspeex/testenc.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#define FRAME_SIZE 128
+#define FRAME_SIZE 160
 
 int main(int argc, char **argv)
 {