path: root/sys/src/games/mp3enc/takehiro.c

/*
 *	MP3 huffman table selecting and bit counting
 *
 *	Copyright (c) 1999 Takehiro TOMINAGA
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/* $Id: takehiro.c,v 1.18 2001/02/27 09:59:18 robert Exp $ */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <assert.h>
#include "util.h"
#include "l3side.h"
#include "tables.h"
#include "quantize_pvt.h"

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif

static const struct
{
    const int region0_count;
    const int region1_count;
} subdv_table[ 23 ] =
{
{0, 0}, /* 0 bands */
{0, 0}, /* 1 bands */
{0, 0}, /* 2 bands */
{0, 0}, /* 3 bands */
{0, 0}, /* 4 bands */
{0, 1}, /* 5 bands */
{1, 1}, /* 6 bands */
{1, 1}, /* 7 bands */
{1, 2}, /* 8 bands */
{2, 2}, /* 9 bands */
{2, 3}, /* 10 bands */
{2, 3}, /* 11 bands */
{3, 4}, /* 12 bands */
{3, 4}, /* 13 bands */
{3, 4}, /* 14 bands */
{4, 5}, /* 15 bands */
{4, 5}, /* 16 bands */
{4, 6}, /* 17 bands */
{5, 6}, /* 18 bands */
{5, 6}, /* 19 bands */
{5, 7}, /* 20 bands */
{6, 7}, /* 21 bands */
{6, 7}, /* 22 bands */
};




/*************************************************************************/
/*	      ix_max							 */
/*************************************************************************/

int 
ix_max(const int *ix, const int *end)
{
    int max1 = 0, max2 = 0;

    do {
	int x1 = *ix++;
	int x2 = *ix++;
	if (max1 < x1) 
	    max1 = x1;

	if (max2 < x2) 
	    max2 = x2;
    } while (ix < end);
    if (max1 < max2) 
	max1 = max2;
    return max1;
}

int
count_bit_ESC( 
    const int *       ix, 
    const int * const end, 
          int         t1,
    const int         t2,
          int * const s )
{
    /* ESC-table is used */
    int linbits = ht[t1].xlen * 65536 + ht[t2].xlen;
    int sum = 0, sum2;

    do {
	int x = *ix++;
	int y = *ix++;

	if (x != 0) {
	    if (x > 14) {
		x = 15;
		sum += linbits;
	    }
	    x *= 16;
	}

	if (y != 0) {
	    if (y > 14) {
		y = 15;
		sum += linbits;
	    }
	    x += y;
	}

	sum += largetbl[x];
    } while (ix < end);

    sum2 = sum & 0xffff;
    sum >>= 16;

    if (sum > sum2) {
	sum = sum2;
	t1 = t2;
    }

    *s += sum;
    return t1;
}


inline static int
count_bit_noESC(const int * ix, const int * const end, int * const s)
{
    /* No ESC-words */
    int	sum1 = 0;
    const char *hlen1 = ht[1].hlen;

    do {
	int x = ix[0] * 2 + ix[1];
	ix += 2;
	sum1 += hlen1[x];
    } while (ix < end);

    *s += sum1;
    return 1;
}



inline static int
count_bit_noESC_from2(
    const int *       ix, 
    const int * const end,
          int         t1,
          int * const s )
{
    /* No ESC-words */
    unsigned int sum = 0, sum2;
    const int xlen = ht[t1].xlen;
    const unsigned int *hlen;
    if (t1 == 2)
	hlen = table23;
    else
	hlen = table56;

    do {
	int x = ix[0] * xlen + ix[1];
	ix += 2;
	sum += hlen[x];
    } while (ix < end);

    sum2 = sum & 0xffff;
    sum >>= 16;

    if (sum > sum2) {
	sum = sum2;
	t1++;
    }

    *s += sum;
    return t1;
}


inline static int
count_bit_noESC_from3(
    const int *       ix, 
    const int * const end,
          int         t1,
          int * const s )
{
    /* No ESC-words */
    int	sum1 = 0;
    int	sum2 = 0;
    int	sum3 = 0;
    const int xlen = ht[t1].xlen;
    const char *hlen1 = ht[t1].hlen;
    const char *hlen2 = ht[t1+1].hlen;
    const char *hlen3 = ht[t1+2].hlen;
    int t;

    do {
	int x = ix[0] * xlen + ix[1];
	ix += 2;
	sum1 += hlen1[x];
	sum2 += hlen2[x];
	sum3 += hlen3[x];
    } while (ix < end);

    t = t1;
    if (sum1 > sum2) {
	sum1 = sum2;
	t++;
    }
    if (sum1 > sum3) {
	sum1 = sum3;
	t = t1+2;
    }
    *s += sum1;

    return t;
}


/*************************************************************************/
/*	      choose table						 */
/*************************************************************************/

/*
  Choose the Huffman table that will encode ix[begin..end] with
  the fewest bits.

  Note: This code contains knowledge about the sizes and characteristics
  of the Huffman tables as defined in the IS (Table B.7), and will not work
  with any arbitrary tables.
*/

static int
choose_table_nonMMX(
    const int *       ix, 
    const int * const end,
          int * const s )
{
    int max;
    int choice, choice2;
    static const int huf_tbl_noESC[] = {
	1, 2, 5, 7, 7,10,10,13,13,13,13,13,13,13,13 /* char not enough ? */
    };

    max = ix_max(ix, end);

    switch (max) {
    case 0:
	return max;

    case 1:
	return count_bit_noESC(ix, end, s);

    case 2:
    case 3:
	return count_bit_noESC_from2(ix, end, huf_tbl_noESC[max - 1], s);

    case 4: case 5: case 6:
    case 7: case 8: case 9:
    case 10: case 11: case 12:
    case 13: case 14: case 15:
	return count_bit_noESC_from3(ix, end, huf_tbl_noESC[max - 1], s);

    default:
	/* try tables with linbits */
	if (max > IXMAX_VAL) {
	    *s = LARGE_BITS;
	    return -1;
	}
	max -= 15;
	for (choice2 = 24; choice2 < 32; choice2++) {
	    if (ht[choice2].linmax >= max) {
		break;
	    }
	}

	for (choice = choice2 - 8; choice < 24; choice++) {
	    if (ht[choice].linmax >= max) {
		break;
	    }
	}
	return count_bit_ESC(ix, end, choice, choice2, s);
    }
}



/*************************************************************************/
/*	      count_bit							 */
/*************************************************************************/

/*
 Function: Count the number of bits necessary to code the subregion. 
*/


int count_bits_long(lame_internal_flags * const gfc, const int ix[576], gr_info * const gi)
{
    int i, a1, a2;
    int bits = 0;

    i=576;
    /* Determine count1 region */
    for (; i > 1; i -= 2) 
	if (ix[i - 1] | ix[i - 2])
	    break;
    gi->count1 = i;

    /* Determines the number of bits to encode the quadruples. */
    a1 = a2 = 0;
    for (; i > 3; i -= 4) {
	int p;
	/* hack to check if all values <= 1 */
	if ((unsigned int)(ix[i-1] | ix[i-2] | ix[i-3] | ix[i-4]) > 1)
	    break;

	p = ((ix[i-4] * 2 + ix[i-3]) * 2 + ix[i-2]) * 2 + ix[i-1];
	a1 += t32l[p];
	a2 += t33l[p];
    }

    bits = a1;
    gi->count1table_select = 0;
    if (a1 > a2) {
	bits = a2;
	gi->count1table_select = 1;
    }

    gi->count1bits = bits;
    gi->big_values = i;
    if (i == 0)
	return bits;

    if (gi->block_type == SHORT_TYPE) {
      a1=3*gfc->scalefac_band.s[3];
      if (a1 > gi->big_values) a1 = gi->big_values;
      a2 = gi->big_values;

    }else if (gi->block_type == NORM_TYPE) {
	assert(i <= 576); /* bv_scf has 576 entries (0..575) */
        a1 = gi->region0_count = gfc->bv_scf[i-2];
	a2 = gi->region1_count = gfc->bv_scf[i-1];

//	assert(a1+a2+2 < SBPSY_l);
        a2 = gfc->scalefac_band.l[a1 + a2 + 2];
	a1 = gfc->scalefac_band.l[a1 + 1];
	if (a2 < i)
	  gi->table_select[2] = gfc->choose_table(ix + a2, ix + i, &bits);

    } else {
	gi->region0_count = 7;
	/*gi->region1_count = SBPSY_l - 7 - 1;*/
	gi->region1_count = SBMAX_l -1 - 7 - 1;
	a1 = gfc->scalefac_band.l[7 + 1];
	a2 = i;
	if (a1 > a2) {
	    a1 = a2;
	}
    }


    /* have to allow for the case when bigvalues < region0 < region1 */
    /* (and region0, region1 are ignored) */
    a1 = Min(a1,i);
    a2 = Min(a2,i);
    
//	assert( a1 >= 0 );
//	assert( a2 >= 0 );

    /* Count the number of bits necessary to code the bigvalues region. */
    if (0 < a1)
      gi->table_select[0] = gfc->choose_table(ix, ix + a1, &bits);
    if (a1 < a2)
      gi->table_select[1] = gfc->choose_table(ix + a1, ix + a2, &bits);
    return bits;
}





int count_bits(
          lame_internal_flags * const gfc, 
          int     * const ix,
    const FLOAT8  * const xr,
          gr_info * const cod_info)  
{
  int bits=0,i;
  /* since quantize_xrpow uses table lookup, we need to check this first: */
  FLOAT8 w = (IXMAX_VAL) / IPOW20(cod_info->global_gain);
  for ( i = 0; i < 576; i++ )  {
    if (xr[i] > w)
      return LARGE_BITS;
  }

  if (gfc->quantization) 
    quantize_xrpow(xr, ix, IPOW20(cod_info->global_gain));
  else
    quantize_xrpow_ISO(xr, ix, IPOW20(cod_info->global_gain));

  bits=count_bits_long(gfc, ix, cod_info);

  return bits;
}

/***********************************************************************
  re-calculate the best scalefac_compress using scfsi
  the saved bits are kept in the bit reservoir.
 **********************************************************************/


inline static void
recalc_divide_init(
    const lame_internal_flags * const gfc,
          gr_info         cod_info,
          int     * const ix,
          int             r01_bits[],
          int             r01_div [],
          int             r0_tbl  [],
          int             r1_tbl  [] )
{
    int r0, r1, bigv, r0t, r1t, bits;

    bigv = cod_info.big_values;

    for (r0 = 0; r0 <= 7 + 15; r0++) {
	r01_bits[r0] = LARGE_BITS;
    }

    for (r0 = 0; r0 < 16; r0++) {
	int a1 = gfc->scalefac_band.l[r0 + 1], r0bits;
	if (a1 >= bigv)
	    break;
	r0bits = cod_info.part2_length;
	r0t = gfc->choose_table(ix, ix + a1, &r0bits);

	for (r1 = 0; r1 < 8; r1++) {
	    int a2 = gfc->scalefac_band.l[r0 + r1 + 2];
	    if (a2 >= bigv)
		break;

	    bits = r0bits;
	    r1t = gfc->choose_table(ix + a1, ix + a2, &bits);
	    if (r01_bits[r0 + r1] > bits) {
		r01_bits[r0 + r1] = bits;
		r01_div[r0 + r1] = r0;
		r0_tbl[r0 + r1] = r0t;
		r1_tbl[r0 + r1] = r1t;
	    }
	}
    }
}

inline static void
recalc_divide_sub(
    const lame_internal_flags * const gfc,
    const gr_info         cod_info2,
          gr_info * const gi,
    const int     * const ix,
    const int             r01_bits[],
    const int             r01_div [],
    const int             r0_tbl  [],
    const int             r1_tbl  [] )
{
    int bits, r2, a2, bigv, r2t;

    bigv = cod_info2.big_values;

    for (r2 = 2; r2 < SBMAX_l + 1; r2++) {
	a2 = gfc->scalefac_band.l[r2];
	if (a2 >= bigv) 
	    break;

	bits = r01_bits[r2 - 2] + cod_info2.count1bits;
	if (gi->part2_3_length <= bits)
	    break;

	r2t = gfc->choose_table(ix + a2, ix + bigv, &bits);
	if (gi->part2_3_length <= bits)
	    continue;

	memcpy(gi, &cod_info2, sizeof(gr_info));
	gi->part2_3_length = bits;
	gi->region0_count = r01_div[r2 - 2];
	gi->region1_count = r2 - 2 - r01_div[r2 - 2];
	gi->table_select[0] = r0_tbl[r2 - 2];
	gi->table_select[1] = r1_tbl[r2 - 2];
	gi->table_select[2] = r2t;
    }
}




void best_huffman_divide(
    const lame_internal_flags * const gfc,
    const int             gr, 
    const int             ch,
          gr_info * const gi,
          int     * const ix )
{
    int i, a1, a2;
    gr_info cod_info2;

    int r01_bits[7 + 15 + 1];
    int r01_div[7 + 15 + 1];
    int r0_tbl[7 + 15 + 1];
    int r1_tbl[7 + 15 + 1];


    /* SHORT BLOCK stuff fails for MPEG2 */ 
    if (gi->block_type == SHORT_TYPE && gfc->mode_gr==1) 
          return;


    memcpy(&cod_info2, gi, sizeof(gr_info));
    if (gi->block_type == NORM_TYPE) {
	recalc_divide_init(gfc, cod_info2, ix, r01_bits,r01_div,r0_tbl,r1_tbl);
	recalc_divide_sub(gfc, cod_info2, gi, ix, r01_bits,r01_div,r0_tbl,r1_tbl);
    }

    i = cod_info2.big_values;
    if (i == 0 || (unsigned int)(ix[i-2] | ix[i-1]) > 1)
	return;

    i = gi->count1 + 2;
    if (i > 576)
	return;

    /* Determines the number of bits to encode the quadruples. */
    memcpy(&cod_info2, gi, sizeof(gr_info));
    cod_info2.count1 = i;
    a1 = a2 = 0;

    assert(i <= 576);
    
    for (; i > cod_info2.big_values; i -= 4) {
	int p = ((ix[i-4] * 2 + ix[i-3]) * 2 + ix[i-2]) * 2 + ix[i-1];
	a1 += t32l[p];
	a2 += t33l[p];
    }
    cod_info2.big_values = i;

    cod_info2.count1table_select = 0;
    if (a1 > a2) {
	a1 = a2;
	cod_info2.count1table_select = 1;
    }

    cod_info2.count1bits = a1;
    cod_info2.part2_3_length = a1 + cod_info2.part2_length;

    if (cod_info2.block_type == NORM_TYPE)
	recalc_divide_sub(gfc, cod_info2, gi, ix, r01_bits,r01_div,r0_tbl,r1_tbl);
    else {
	/* Count the number of bits necessary to code the bigvalues region. */
	a1 = gfc->scalefac_band.l[7 + 1];
	if (a1 > i) {
	    a1 = i;
	}
	if (a1 > 0)
	  cod_info2.table_select[0] =
	    gfc->choose_table(ix, ix + a1, (int *)&cod_info2.part2_3_length);
	if (i > a1)
	  cod_info2.table_select[1] =
	    gfc->choose_table(ix + a1, ix + i, (int *)&cod_info2.part2_3_length);
	if (gi->part2_3_length > cod_info2.part2_3_length)
	    memcpy(gi, &cod_info2, sizeof(gr_info));
    }
}

static const int slen1_n[16] = { 1, 1, 1, 1, 8, 2, 2, 2, 4, 4, 4, 8, 8, 8,16,16 };
static const int slen2_n[16] = { 1, 2, 4, 8, 1, 2, 4, 8, 2, 4, 8, 2, 4, 8, 4, 8 };

void
scfsi_calc(int ch,
	   III_side_info_t *l3_side,
	   III_scalefac_t scalefac[2][2])
{
    int i, s1, s2, c1, c2;
    int sfb;
    gr_info *gi = &l3_side->gr[1].ch[ch].tt;

    static const int scfsi_band[5] = { 0, 6, 11, 16, 21 };
#if 0
    static const int slen1_n[16] = { 0, 1, 1, 1, 8, 2, 2, 2, 4, 4, 4, 8, 8, 8,16,16 };
    static const int slen2_n[16] = { 0, 2, 4, 8, 1, 2, 4, 8, 2, 4, 8, 2, 4, 8, 4, 8 };
#endif

    for (i = 0; i < 4; i++) 
	l3_side->scfsi[ch][i] = 0;

    for (i = 0; i < (sizeof(scfsi_band) / sizeof(int)) - 1; i++) {
	for (sfb = scfsi_band[i]; sfb < scfsi_band[i + 1]; sfb++) {
	    if (scalefac[0][ch].l[sfb] != scalefac[1][ch].l[sfb])
		break;
	}
	if (sfb == scfsi_band[i + 1]) {
	    for (sfb = scfsi_band[i]; sfb < scfsi_band[i + 1]; sfb++) {
		scalefac[1][ch].l[sfb] = -1;
	    }
	    l3_side->scfsi[ch][i] = 1;
	}
    }

    s1 = c1 = 0;
    for (sfb = 0; sfb < 11; sfb++) {
	if (scalefac[1][ch].l[sfb] < 0)
	    continue;
	c1++;
	if (s1 < scalefac[1][ch].l[sfb])
	    s1 = scalefac[1][ch].l[sfb];
    }

    s2 = c2 = 0;
    for (; sfb < SBPSY_l; sfb++) {
	if (scalefac[1][ch].l[sfb] < 0)
	    continue;
	c2++;
	if (s2 < scalefac[1][ch].l[sfb])
	    s2 = scalefac[1][ch].l[sfb];
    }

    for (i = 0; i < 16; i++) {
	if (s1 < slen1_n[i] && s2 < slen2_n[i]) {
	    int c = slen1_tab[i] * c1 + slen2_tab[i] * c2;
	    if (gi->part2_length > c) {
		gi->part2_length = c;
		gi->scalefac_compress = i;
	    }
	}
    }
}

/*
Find the optimal way to store the scalefactors.
Only call this routine after final scalefactors have been
chosen and the channel/granule will not be re-encoded.
 */
void best_scalefac_store(
    const lame_internal_flags *gfc,
    const int             gr,
    const int             ch,
          int             l3_enc[2][2][576],
          III_side_info_t * const l3_side,
          III_scalefac_t          scalefac[2][2] )
{

    /* use scalefac_scale if we can */
    gr_info *gi = &l3_side->gr[gr].ch[ch].tt;
    int sfb,i,j,j2,l,start,end;

    /* remove scalefacs from bands with ix=0.  This idea comes
     * from the AAC ISO docs.  added mt 3/00 */
    /* check if l3_enc=0 */
    for ( sfb = 0; sfb < gi->sfb_lmax; sfb++ ) {
      if (scalefac[gr][ch].l[sfb]>0) { 
	start = gfc->scalefac_band.l[ sfb ];
	end   = gfc->scalefac_band.l[ sfb+1 ];
	for ( l = start; l < end; l++ ) if (l3_enc[gr][ch][l]!=0) break;
	if (l==end) scalefac[gr][ch].l[sfb]=0;
      }
    }
    for ( j=0, sfb = gi->sfb_smin; sfb < SBPSY_s; sfb++ ) {
	start = gfc->scalefac_band.s[ sfb ];
	end   = gfc->scalefac_band.s[ sfb+1 ];
	for ( i = 0; i < 3; i++ ) {
	  if (scalefac[gr][ch].s[sfb][i]>0) {
	    j2 = j;
	    for ( l = start; l < end; l++ ) 
	      if (l3_enc[gr][ch][j2++ /*3*l+i*/]!=0) break;
	    if (l==end) scalefac[gr][ch].s[sfb][i]=0;
	  }
	  j += end-start;
	}
    }


    gi->part2_3_length -= gi->part2_length;
    if (!gi->scalefac_scale && !gi->preflag) {
	int b, s = 0;
	for (sfb = 0; sfb < gi->sfb_lmax; sfb++) {
	    s |= scalefac[gr][ch].l[sfb];
	}

	for (sfb = gi->sfb_smin; sfb < SBPSY_s; sfb++) {
	    for (b = 0; b < 3; b++) {
		s |= scalefac[gr][ch].s[sfb][b];
	    }
	}

	if (!(s & 1) && s != 0) {
	    for (sfb = 0; sfb < gi->sfb_lmax; sfb++) {
		scalefac[gr][ch].l[sfb] /= 2;
	    }
	    for (sfb = gi->sfb_smin; sfb < SBPSY_s; sfb++) {
		for (b = 0; b < 3; b++) {
		    scalefac[gr][ch].s[sfb][b] /= 2;
		}
	    }

	    gi->scalefac_scale = 1;
	    gi->part2_length = 99999999;
	    if (gfc->mode_gr == 2) {
	        scale_bitcount(&scalefac[gr][ch], gi);
	    } else {
		scale_bitcount_lsf(gfc,&scalefac[gr][ch], gi);
	    }
	}
    }


    for ( i = 0; i < 4; i++ )
      l3_side->scfsi[ch][i] = 0;

    if (gfc->mode_gr==2 && gr == 1
	&& l3_side->gr[0].ch[ch].tt.block_type != SHORT_TYPE
	&& l3_side->gr[1].ch[ch].tt.block_type != SHORT_TYPE) {
      	scfsi_calc(ch, l3_side, scalefac);
    }
    gi->part2_3_length += gi->part2_length;
}


/* number of bits used to encode scalefacs */

/* 18*slen1_tab[i] + 18*slen2_tab[i] */
static const int scale_short[16] = {
    0, 18, 36, 54, 54, 36, 54, 72, 54, 72, 90, 72, 90, 108, 108, 126 };

/* 17*slen1_tab[i] + 18*slen2_tab[i] */
static const int scale_mixed[16] = {
    0, 18, 36, 54, 51, 35, 53, 71, 52, 70, 88, 69, 87, 105, 104, 122 };

/* 11*slen1_tab[i] + 10*slen2_tab[i] */
static const int scale_long[16] = {
    0, 10, 20, 30, 33, 21, 31, 41, 32, 42, 52, 43, 53, 63, 64, 74 };


/*************************************************************************/
/*            scale_bitcount                                             */
/*************************************************************************/

/* Also calculates the number of bits necessary to code the scalefactors. */

int scale_bitcount( 
    III_scalefac_t * const scalefac, gr_info * const cod_info)
{
    int i, k, sfb, max_slen1 = 0, max_slen2 = 0, ep = 2;

    /* maximum values */
    const int *tab;


    if ( cod_info->block_type == SHORT_TYPE ) {
	tab = scale_short;
	if (cod_info->mixed_block_flag) {
	    tab = scale_mixed;
	    for ( sfb = 0 ; sfb < cod_info->sfb_lmax; sfb++ )
		if (max_slen1 < scalefac->l[sfb])
		    max_slen1 = scalefac->l[sfb];
	}

	for ( i = 0; i < 3; i++ ) {
	    for ( sfb = cod_info->sfb_smin; sfb < 6; sfb++ )
		if (max_slen1 < scalefac->s[sfb][i])
		    max_slen1 = scalefac->s[sfb][i];
	    for (sfb = 6; sfb < SBPSY_s; sfb++ )
		if (max_slen2 < scalefac->s[sfb][i])
		    max_slen2 = scalefac->s[sfb][i];
	}
    }
    else
    { /* block_type == 1,2,or 3 */
        tab = scale_long;
        for ( sfb = 0; sfb < 11; sfb++ )
            if ( scalefac->l[sfb] > max_slen1 )
                max_slen1 = scalefac->l[sfb];

	if (!cod_info->preflag) {
	    for ( sfb = 11; sfb < SBPSY_l; sfb++ )
		if (scalefac->l[sfb] < pretab[sfb])
		    break;

	    if (sfb == SBPSY_l) {
		cod_info->preflag = 1;
		for ( sfb = 11; sfb < SBPSY_l; sfb++ )
		    scalefac->l[sfb] -= pretab[sfb];
	    }
	}

        for ( sfb = 11; sfb < SBPSY_l; sfb++ )
            if ( scalefac->l[sfb] > max_slen2 )
                max_slen2 = scalefac->l[sfb];
    }


    /* from Takehiro TOMINAGA <tominaga@isoternet.org> 10/99
     * loop over *all* posible values of scalefac_compress to find the
     * one which uses the smallest number of bits.  ISO would stop
     * at first valid index */
    cod_info->part2_length = LARGE_BITS;
    for ( k = 0; k < 16; k++ )
    {
        if ( (max_slen1 < slen1_n[k]) && (max_slen2 < slen2_n[k]) &&
             (cod_info->part2_length > tab[k])) {
	  cod_info->part2_length=tab[k];
	  cod_info->scalefac_compress=k;
	  ep=0;  /* we found a suitable scalefac_compress */
	}
    }
    return ep;
}



/*
  table of largest scalefactor values for MPEG2
*/
static const int max_range_sfac_tab[6][4] =
{
 { 15, 15, 7,  7},
 { 15, 15, 7,  0},
 { 7,  3,  0,  0},
 { 15, 31, 31, 0},
 { 7,  7,  7,  0},
 { 3,  3,  0,  0}
};




/*************************************************************************/
/*            scale_bitcount_lsf                                         */
/*************************************************************************/

/* Also counts the number of bits to encode the scalefacs but for MPEG 2 */ 
/* Lower sampling frequencies  (24, 22.05 and 16 kHz.)                   */
 
/*  This is reverse-engineered from section 2.4.3.2 of the MPEG2 IS,     */
/* "Audio Decoding Layer III"                                            */

int scale_bitcount_lsf(const lame_internal_flags *gfc,
    const III_scalefac_t * const scalefac, gr_info * const cod_info)
{
    int table_number, row_in_table, partition, nr_sfb, window, over;
    int i, sfb, max_sfac[ 4 ];
    const int *partition_table;

    /*
      Set partition table. Note that should try to use table one,
      but do not yet...
    */
    if ( cod_info->preflag )
	table_number = 2;
    else
	table_number = 0;

    for ( i = 0; i < 4; i++ )
	max_sfac[i] = 0;

    if ( cod_info->block_type == SHORT_TYPE )
    {
	    row_in_table = 1;
	    partition_table = &nr_of_sfb_block[table_number][row_in_table][0];
	    for ( sfb = 0, partition = 0; partition < 4; partition++ )
	    {
		nr_sfb = partition_table[ partition ] / 3;
		for ( i = 0; i < nr_sfb; i++, sfb++ )
		    for ( window = 0; window < 3; window++ )
			if ( scalefac->s[sfb][window] > max_sfac[partition] )
			    max_sfac[partition] = scalefac->s[sfb][window];
	    }
    }
    else
    {
	row_in_table = 0;
	partition_table = &nr_of_sfb_block[table_number][row_in_table][0];
	for ( sfb = 0, partition = 0; partition < 4; partition++ )
	{
	    nr_sfb = partition_table[ partition ];
	    for ( i = 0; i < nr_sfb; i++, sfb++ )
		if ( scalefac->l[sfb] > max_sfac[partition] )
		    max_sfac[partition] = scalefac->l[sfb];
	}
    }

    for ( over = 0, partition = 0; partition < 4; partition++ )
    {
	if ( max_sfac[partition] > max_range_sfac_tab[table_number][partition] )
	    over++;
    }
    if ( !over )
    {
	/*
	  Since no bands have been over-amplified, we can set scalefac_compress
	  and slen[] for the formatter
	*/
	static const int log2tab[] = { 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4 };

	int slen1, slen2, slen3, slen4;

        cod_info->sfb_partition_table = nr_of_sfb_block[table_number][row_in_table];
	for ( partition = 0; partition < 4; partition++ )
	    cod_info->slen[partition] = log2tab[max_sfac[partition]];

	/* set scalefac_compress */
	slen1 = cod_info->slen[ 0 ];
	slen2 = cod_info->slen[ 1 ];
	slen3 = cod_info->slen[ 2 ];
	slen4 = cod_info->slen[ 3 ];

	switch ( table_number )
	{
	  case 0:
	    cod_info->scalefac_compress = (((slen1 * 5) + slen2) << 4)
		+ (slen3 << 2)
		+ slen4;
	    break;

	  case 1:
	    cod_info->scalefac_compress = 400
		+ (((slen1 * 5) + slen2) << 2)
		+ slen3;
	    break;

	  case 2:
	    cod_info->scalefac_compress = 500 + (slen1 * 3) + slen2;
	    break;

	  default:
	    ERRORF(gfc,"intensity stereo not implemented yet\n" );
	    break;
	}
    }
#ifdef DEBUG
    if ( over ) 
        ERRORF(gfc, "---WARNING !! Amplification of some bands over limits\n" );
#endif
    if (!over) {
      assert( cod_info->sfb_partition_table );     
      cod_info->part2_length=0;
      for ( partition = 0; partition < 4; partition++ )
	cod_info->part2_length += cod_info->slen[partition] * cod_info->sfb_partition_table[partition];
    }
    return over;
}



void huffman_init(lame_internal_flags * const gfc)
{
    int i;

    gfc->choose_table = choose_table_nonMMX;
    
#ifdef MMX_choose_table
    if (gfc->CPU_features.MMX) {
        extern int choose_table_MMX(const int *ix, const int *end, int *s);
        gfc->choose_table = choose_table_MMX;
    }
#endif

    for (i = 2; i <= 576; i += 2) {
	int scfb_anz = 0, index;
	while (gfc->scalefac_band.l[++scfb_anz] < i)
	    ;

	index = subdv_table[scfb_anz].region0_count;
	while (gfc->scalefac_band.l[index + 1] > i)
	    index--;

	if (index < 0) {
	  /* this is an indication that everything is going to
	     be encoded as region0:  bigvalues < region0 < region1
	     so lets set region0, region1 to some value larger
	     than bigvalues */
	  index = subdv_table[scfb_anz].region0_count;
	}

	gfc->bv_scf[i-2] = index;

	index = subdv_table[scfb_anz].region1_count;
	while (gfc->scalefac_band.l[index + gfc->bv_scf[i-2] + 2] > i)
	    index--;

	if (index < 0) {
	  index = subdv_table[scfb_anz].region1_count;
	}

	gfc->bv_scf[i-1] = index;
    }
}