shithub: opus

Info  •  Files  •  Log  •  Branches

fixed-point: More work on the PLC

--- a/libcelt/celt.c

+++ b/libcelt/celt.c

@@ -1514,8 +1514,8 @@

       celt_word32 e[2*MAX_PERIOD];

       celt_word16 exc[2*MAX_PERIOD];

       celt_word32 ac[LPC_ORDER+1];

-      float decay = 1;

-      float S1=0;

+      celt_word16 decay = 1;

+      celt_word32 S1=0;

       celt_word16 mem[LPC_ORDER]={0};

       offset = MAX_PERIOD-pitch_index;

@@ -1528,12 +1528,20 @@

                         LPC_ORDER, MAX_PERIOD);

          /* Noise floor -40 dB */

+#ifdef FIXED_POINT

+         ac[0] += SHR32(ac[0],13);

+#else

          ac[0] *= 1.0001;

+#endif

          /* Lag windowing */

          for (i=1;i<=LPC_ORDER;i++)

          {

             /*ac[i] *= exp(-.5*(2*M_PI*.002*i)*(2*M_PI*.002*i));*/

+#ifdef FIXED_POINT

+            ac[i] -= MULT16_32_Q15(2*i*i, ac[i]);

+#else

             ac[i] -= ac[i]*(.008*i)*(.008*i);

+#endif

          }

          _celt_lpc(st->lpc+c*LPC_ORDER, ac, LPC_ORDER);

@@ -1542,7 +1550,7 @@

       /*for (i=0;i<MAX_PERIOD;i++)printf("%d ", exc[i]); printf("\n");*/

       /* Check if the waveform is decaying (and if so how fast) */

       {

-         float E1=0, E2=0;

+         celt_word32 E1=1, E2=1;

          int period;

          if (pitch_index <= MAX_PERIOD/2)

             period = pitch_index;

@@ -1550,12 +1558,12 @@

             period = MAX_PERIOD/2;

          for (i=0;i<period;i++)

          {

-            E1 += exc[MAX_PERIOD-period+i]*exc[MAX_PERIOD-period+i];

-            E2 += exc[MAX_PERIOD-2*period+i]*exc[MAX_PERIOD-2*period+i];

+            E1 += SHR32(MULT16_16(exc[MAX_PERIOD-period+i],exc[MAX_PERIOD-period+i]),8);

+            E2 += SHR32(MULT16_16(exc[MAX_PERIOD-2*period+i],exc[MAX_PERIOD-2*period+i]),8);

          }

-         decay = sqrt((E1+1)/(E2+1));

-         if (decay > 1)

-            decay = 1;

+         if (E1 > E2)

+            E1 = E2;

+         decay = celt_sqrt(frac_div32(SHR(E1,1),E2));

       }

       /* Copy excitation, taking decay into account */

@@ -1564,18 +1572,18 @@

          if (offset+i >= MAX_PERIOD)

          {

             offset -= pitch_index;

-            decay *= decay;

+            decay = MULT16_16_Q15(decay, decay);

          }

-         e[i] = decay*SHL32(EXTEND32(exc[offset+i]), SIG_SHIFT);

-         S1 += st->out_mem[offset+i]*1.*st->out_mem[offset+i];

+         e[i] = SHL32(EXTEND32(MULT16_16_Q15(decay, exc[offset+i])), SIG_SHIFT);

+         S1 += SHR32(MULT16_16(st->out_mem[offset+i],st->out_mem[offset+i]),8);

       }

       iir(e, st->lpc+c*LPC_ORDER, e, len+st->mode->overlap, LPC_ORDER, mem);

       {

-         float S2=0;

+         celt_word32 S2=0;

          for (i=0;i<len+overlap;i++)

-            S2 += e[i]*1.*e[i];

+            S2 += SHR32(MULT16_16(e[i],e[i]),8);

          /* This checks for an "explosion" in the synthesis (including NaNs) */

          if (!(S1 > 0.2f*S2))

          {

@@ -1583,7 +1591,7 @@

                e[i] = 0;

          } else if (S1 < S2)

          {

-            float ratio = sqrt((S1+1)/(S2+1));

+            float ratio = sqrt((S1+1.)/(S2+1.));

             for (i=0;i<len+overlap;i++)

                e[i] *= ratio;

          }

--- a/libcelt/plc.c

+++ b/libcelt/plc.c

@@ -24,7 +24,7 @@

 #endif

-float _celt_lpc(

+void _celt_lpc(

       celt_word16       *_lpc, /* out: [0...p-1] LPC coefficients      */

 const celt_word32 *ac,  /* in:  [0...p] autocorrelation values  */

 int          p

@@ -76,7 +76,6 @@

    for (i=0;i<p;i++)

       _lpc[i] = ROUND16(lpc[i],16);

 #endif

-   return error;

 }

 void fir(const celt_word16 *x,