shithub: opus

Info  •  Files  •  Log  •  Branches

Speed up the bit allocator interpolation

--- a/libcelt/rate.c

+++ b/libcelt/rate.c

@@ -143,9 +143,14 @@

    int lo, hi;

    int i, j;

    int logM;

+   int psum0;

    const int C = CHANNELS(_C);

    SAVE_STACK;

+   psum0=0;

+   for (j=start;j<end;j++)

+      psum0 += bits1[j];

+

    logM = LM<<BITRES;

    lo = 0;

    hi = 1<<ALLOC_STEPS;

@@ -152,9 +157,9 @@

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

    {

       int mid = (lo+hi)>>1;

-      psum = 0;

+      psum = psum0;

       for (j=start;j<end;j++)

-         psum += (((1<<ALLOC_STEPS)-mid)*bits1[j] + mid*bits2[j])>>ALLOC_STEPS;

+         psum += (mid*bits2[j]>>ALLOC_STEPS);

       if (psum > (total<<BITRES))

          hi = mid;

       else

@@ -164,7 +169,7 @@

    /*printf ("interp bisection gave %d\n", lo);*/

    for (j=start;j<end;j++)

    {

-      bits[j] = (((1<<ALLOC_STEPS)-lo)*bits1[j] + lo*bits2[j])>>ALLOC_STEPS;

+      bits[j] = bits1[j] + (lo*bits2[j]>>ALLOC_STEPS);

       psum += bits[j];

    }

    /* Allocate the remaining bits */

@@ -270,8 +275,9 @@

    for (j=start;j<end;j++)

    {

       int N = m->eBands[j+1]-m->eBands[j];

-      bits1[j] = (C*N*m->allocVectors[lo*len+j]<<LM>>2) + offsets[j];

-      bits2[j] = (C*N*m->allocVectors[hi*len+j]<<LM>>2) + offsets[j];

+      bits1[j] = (C*N*m->allocVectors[lo*len+j]<<LM>>2);

+      bits2[j] = (C*N*m->allocVectors[hi*len+j]<<LM>>2) - bits1[j];

+      bits1[j] += offsets[j];

    }

    interp_bits2pulses(m, start, end, bits1, bits2, total, pulses, ebits, fine_priority, len, C, LM);

    RESTORE_STACK;