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Saving ~1 kB by using chars for the alloc table

Also a bunch of comments

--- a/libcelt/bands.c

+++ b/libcelt/bands.c

@@ -424,6 +424,10 @@

    return *last_decision;

 }

+/* This function is responsible for encoding and decoding a band for both

+   the mono and stereo case. Even in the mono case, it can split the band

+   in two and transmit the energy difference with the two half-bands. It

+   can be called recursively so bands can end up being split in 8 parts. */

 static void quant_band(int encode, const CELTMode *m, int i, celt_norm *X, celt_norm *Y, int N, int b, int spread, celt_norm *lowband, int resynth, ec_enc *ec, celt_int32 *remaining_bits, int LM, celt_norm *lowband_out, const celt_ener *bandE)

 {

    int q;

@@ -434,6 +438,7 @@

    split = stereo = Y != NULL;

+   /* If we need more than 32 bits, try splitting the band in two. */

    if (!stereo && LM>0 && !fits_in32(N, get_pulses(bits2pulses(m, m->bits[LM][i], N, b))))

    {

       N >>= 1;

@@ -485,6 +490,9 @@

          int fs=1, ft;

          shift = 14-qb;

          ft = ((1<<qb>>1)+1)*((1<<qb>>1)+1);

+

+         /* Entropy coding of the angle. We use a uniform pdf for the

+            first stereo split but a triangular one for the rest. */

          if (encode)

             itheta = (itheta+(1<<shift>>1))>>shift;

          if (stereo || qb>9)

@@ -534,6 +542,7 @@

          }

          itheta <<= shift;

       }

+

       if (itheta == 0)

       {

          imid = 32767;

@@ -549,7 +558,10 @@

          iside = bitexact_cos(16384-itheta);

          delta = (N-1)*(log2_frac(iside,BITRES+2)-log2_frac(imid,BITRES+2))>>2;

       }

-#if 1

+

+      /* This is a special case for N=2 that only works for stereo and takes

+         advantage of the fact that mid and side are orthogonal to encode

+         the side with just one bit. */

       if (N==2 && stereo)

       {

          int c, c2;

@@ -588,6 +600,7 @@

          {

             if (encode)

             {

+               /* Here we only need to encode a sign for the side */

                if (v[0]*w[1] - v[1]*w[0] > 0)

                   sign = 1;

                else

@@ -614,9 +627,8 @@

             y2[1] = v[1];

          }

       } else

-#endif

       {

-

+         /* "Normal" split code */

          mbits = (b-qalloc/2-delta)/2;

          if (mbits > b-qalloc)

             mbits = b-qalloc;

@@ -632,6 +644,7 @@

       }

    } else {

+      /* This is the basis no-split case */

       q = bits2pulses(m, m->bits[LM][i], N, b);

       curr_bits = pulses2bits(m->bits[LM][i], N, q);

       *remaining_bits -= curr_bits;

--- a/libcelt/modes.c

+++ b/libcelt/modes.c

@@ -97,7 +97,7 @@

 int *band_allocation;

 #else

 #define BITALLOC_SIZE 12

-static const int band_allocation[BARK_BANDS*BITALLOC_SIZE] = 

+static const unsigned char band_allocation[BARK_BANDS*BITALLOC_SIZE] =

    /* 0 100 200 300 400 510 630 770 920 1k  1.2 1.5 1.7 2k  2.3 2.7 3.1 3.7 4.4 5.3 6.4 7.7 9.5 12k 15k  */

    {  4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, /*0*/

       2,  2,  1,  1,  2,  2,  1,  1,  1,  1,  1,  1,  1,  1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, /*1*/