xref: /plan9/sys/src/games/mp3enc/quantize.c (revision 8f5875f3e9b20916b4c52ad4336922bc8653eb7b)

/*
 * MP3 quantization
 *
 * Copyright (c) 1999 Mark Taylor
 *
 * 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: quantize.c,v 1.57 2001/02/27 06:14:57 markt Exp $ */

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

#include <math.h>
#include <assert.h>
#include "util.h"
#include "l3side.h"
#include "quantize.h"
#include "reservoir.h"
#include "quantize_pvt.h"
#include "lame-analysis.h"

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


/************************************************************************
 *
 *      init_outer_loop()
 *  mt 6/99
 *
 *  initializes cod_info, scalefac and xrpow
 *
 *  returns 0 if all energies in xr are zero, else 1
 *
 ************************************************************************/

static int
init_outer_loop(
    gr_info *const cod_info,
    III_scalefac_t *const scalefac,
    const int is_mpeg1,
    const FLOAT8 xr[576],
    FLOAT8 xrpow[576] )
{
    FLOAT8 tmp, sum = 0;
    int i;

    /*  initialize fresh cod_info
     */
    cod_info->part2_3_length      = 0;
    cod_info->big_values          = 0;
    cod_info->count1              = 0;
    cod_info->global_gain         = 210;
    cod_info->scalefac_compress   = 0;
    /* window_switching_flag was set in psymodel.c? */
    /* block_type            was set in psymodel.c? */
    /* mixed_block_flag      would be set in ^      */
    cod_info->table_select [0]    = 0;
    cod_info->table_select [1]    = 0;
    cod_info->table_select [2]    = 0;
    cod_info->subblock_gain[0]    = 0;
    cod_info->subblock_gain[1]    = 0;
    cod_info->subblock_gain[2]    = 0;
    cod_info->region0_count       = 0;
    cod_info->region1_count       = 0;
    cod_info->preflag             = 0;
    cod_info->scalefac_scale      = 0;
    cod_info->count1table_select  = 0;
    cod_info->part2_length        = 0;
    if (cod_info->block_type == SHORT_TYPE) {
        cod_info->sfb_lmax        = 0;
        cod_info->sfb_smin        = 0;
	if (cod_info->mixed_block_flag) {
            /*
             *  MPEG-1:      sfbs 0-7 long block, 3-12 short blocks
             *  MPEG-2(.5):  sfbs 0-5 long block, 3-12 short blocks
             */
            cod_info->sfb_lmax    = is_mpeg1 ? 8 : 6;
	    cod_info->sfb_smin    = 3;
	}
    } else {
        cod_info->sfb_lmax        = SBPSY_l;
        cod_info->sfb_smin        = SBPSY_s;
    }
    cod_info->count1bits          = 0;
    cod_info->sfb_partition_table = nr_of_sfb_block[0][0];
    cod_info->slen[0]             = 0;
    cod_info->slen[1]             = 0;
    cod_info->slen[2]             = 0;
    cod_info->slen[3]             = 0;

    /*  fresh scalefactors are all zero
     */
    memset(scalefac, 0, sizeof(III_scalefac_t));

    /*  check if there is some energy we have to quantize
     *  and calculate xrpow matching our fresh scalefactors
     */
    for (i = 0; i < 576; ++i) {
        tmp = fabs (xr[i]);
	sum += tmp;
        xrpow[i] = sqrt (tmp * sqrt(tmp));
    }
   /*  return 1 if we have something to quantize, else 0
    */
   return sum > (FLOAT8)1E-20;
}



/************************************************************************
 *
 *      bin_search_StepSize()
 *
 *  author/date??
 *
 *  binary step size search
 *  used by outer_loop to get a quantizer step size to start with
 *
 ************************************************************************/

typedef enum {
    BINSEARCH_NONE,
    BINSEARCH_UP,
    BINSEARCH_DOWN
} binsearchDirection_t;

int
bin_search_StepSize(
          lame_internal_flags * const gfc,
          gr_info * const cod_info,
    const int             desired_rate,
    const int             start,
    const FLOAT8          xrpow [576],
          int             l3enc [576] )
{
    int nBits;
    int CurrentStep;
    int flag_GoneOver = 0;
    int StepSize      = start;

    binsearchDirection_t Direction = BINSEARCH_NONE;
    assert(gfc->CurrentStep);
    CurrentStep = gfc->CurrentStep;

    do {
        cod_info->global_gain = StepSize;
        nBits = count_bits(gfc,l3enc,xrpow,cod_info);

        if (CurrentStep == 1) break; /* nothing to adjust anymore */

        if (flag_GoneOver) CurrentStep /= 2;

        if (nBits > desired_rate) {
            /* increase Quantize_StepSize */
            if (Direction == BINSEARCH_DOWN && !flag_GoneOver) {
                flag_GoneOver = 1;
                CurrentStep  /= 2; /* late adjust */
            }
            Direction = BINSEARCH_UP;
            StepSize += CurrentStep;
            if (StepSize > 255) break;
        }
        else if (nBits < desired_rate) {
            /* decrease Quantize_StepSize */
            if (Direction == BINSEARCH_UP && !flag_GoneOver) {
                flag_GoneOver = 1;
                CurrentStep  /= 2; /* late adjust */
            }
            Direction = BINSEARCH_DOWN;
            StepSize -= CurrentStep;
            if (StepSize < 0) break;
        }
        else break; /* nBits == desired_rate;; most unlikely to happen.*/
    } while (1); /* For-ever, break is adjusted. */

    CurrentStep = start - StepSize;

    gfc->CurrentStep = CurrentStep/4 != 0 ? 4 : 2;

    return nBits;
}




/***************************************************************************
 *
 *         inner_loop ()
 *
 *  author/date??
 *
 *  The code selects the best global gain for a particular set of scalefacs
 *
 ***************************************************************************/

int
inner_loop(
          lame_internal_flags * const gfc,
          gr_info * const cod_info,
    const int             max_bits,
    const FLOAT8          xrpow [576],
          int             l3enc [576] )
{
    int bits;

    assert(max_bits >= 0);

    /*  scalefactors may have changed, so count bits
     */
    bits=count_bits(gfc,l3enc,xrpow,cod_info);

    /*  increase quantizer stepsize until needed bits are below maximum
     */
    while (bits > max_bits) {
        cod_info->global_gain++;
        bits = count_bits (gfc, l3enc, xrpow, cod_info);
    }

    return bits;
}



/*************************************************************************
 *
 *      loop_break()
 *
 *  author/date??
 *
 *  Function: Returns zero if there is a scalefac which has not been
 *            amplified. Otherwise it returns one.
 *
 *************************************************************************/

inline
static int
loop_break(
    const gr_info        * const cod_info,
    const III_scalefac_t * const scalefac )
{
    unsigned int i, sfb;

    for (sfb = 0; sfb < cod_info->sfb_lmax; sfb++)
        if (scalefac->l[sfb] == 0)
            return 0;

    for (sfb = cod_info->sfb_smin; sfb < SBPSY_s; sfb++)
        for (i = 0; i < 3; i++)
            if (scalefac->s[sfb][i] == 0 && cod_info->subblock_gain[i] == 0)
                return 0;

    return 1;
}




/*************************************************************************
 *
 *      quant_compare()
 *
 *  author/date??
 *
 *  several different codes to decide which quantization is better
 *
 *************************************************************************/

inline
static int
quant_compare(
    const int                       experimentalX,
    const calc_noise_result * const best,
    const calc_noise_result * const calc )
{
    /*
       noise is given in decibels (dB) relative to masking thesholds.

       over_noise:  ??? (the previous comment is fully wrong)
       tot_noise:   ??? (the previous comment is fully wrong)
       max_noise:   max quantization noise

     */
    int better;

    switch (experimentalX) {
        default:
        case 0:
	    better = calc->over_count  < best->over_count
               ||  ( calc->over_count == best->over_count  &&
                     calc->over_noise  < best->over_noise )
               ||  ( calc->over_count == best->over_count  &&
                     calc->over_noise == best->over_noise  &&
                     calc->tot_noise   < best->tot_noise  );
	    break;
        case 1:
	    better = calc->max_noise < best->max_noise;
	    break;
        case 2:
	    better = calc->tot_noise < best->tot_noise;
	    break;
        case 3:
	    better = calc->tot_noise < best->tot_noise  &&
                     calc->max_noise < best->max_noise+2;
	    break;
        case 4:
	    better = ( calc->max_noise <= 0  &&
                       best->max_noise >  2 )
                 ||  ( calc->max_noise <= 0  &&
                       best->max_noise <  0  &&
                       best->max_noise >  calc->max_noise-2  &&
                       calc->tot_noise <  best->tot_noise )
                 ||  ( calc->max_noise <= 0  &&
                       best->max_noise >  0  &&
                       best->max_noise >  calc->max_noise-2  &&
                       calc->tot_noise <  best->tot_noise+best->over_noise )
                 ||  ( calc->max_noise >  0  &&
                       best->max_noise > -0.5  &&
                       best->max_noise >  calc->max_noise-1  &&
                       calc->tot_noise+calc->over_noise < best->tot_noise+best->over_noise )
                 ||  ( calc->max_noise >  0  &&
                       best->max_noise > -1  &&
                       best->max_noise >  calc->max_noise-1.5  &&
                       calc->tot_noise+calc->over_noise+calc->over_noise < best->tot_noise+best->over_noise+best->over_noise );
            break;
        case 5:
	    better =   calc->over_noise  < best->over_noise
                 ||  ( calc->over_noise == best->over_noise  &&
                       calc->tot_noise   < best->tot_noise );
	    break;
        case 6:
	    better =   calc->over_noise  < best->over_noise
                 ||  ( calc->over_noise == best->over_noise  &&
                     ( calc->max_noise   < best->max_noise
		     ||  ( calc->max_noise  == best->max_noise  &&
                           calc->tot_noise  <= best->tot_noise )
		      ));
	    break;
        case 7:
	    better =   calc->over_count < best->over_count
                   ||  calc->over_noise < best->over_noise;
	    break;
        case 8:
	    better =   calc->klemm_noise < best->klemm_noise;
            break;
    }

    return better;
}



/*************************************************************************
 *
 *          amp_scalefac_bands()
 *
 *  author/date??
 *
 *  Amplify the scalefactor bands that violate the masking threshold.
 *  See ISO 11172-3 Section C.1.5.4.3.5
 *
 *  distort[] = noise/masking
 *  distort[] > 1   ==> noise is not masked
 *  distort[] < 1   ==> noise is masked
 *  max_dist = maximum value of distort[]
 *
 *  Three algorithms:
 *  noise_shaping_amp
 *        0             Amplify all bands with distort[]>1.
 *
 *        1             Amplify all bands with distort[] >= max_dist^(.5);
 *                     ( 50% in the db scale)
 *
 *        2             Amplify first band with distort[] >= max_dist;
 *
 *
 *  For algorithms 0 and 1, if max_dist < 1, then amplify all bands
 *  with distort[] >= .95*max_dist.  This is to make sure we always
 *  amplify at least one band.
 *
 *
 *************************************************************************/
static void
amp_scalefac_bands(
    lame_global_flags *gfp,
    const gr_info  *const cod_info,
    III_scalefac_t *const scalefac,
    III_psy_xmin *distort,
    FLOAT8 xrpow[576] )
{
  lame_internal_flags *gfc=gfp->internal_flags;
  int start, end, l,i,j,sfb;
  FLOAT8 ifqstep34, trigger;

  if (cod_info->scalefac_scale == 0) {
    ifqstep34 = 1.29683955465100964055; /* 2**(.75*.5)*/
  } else {
    ifqstep34 = 1.68179283050742922612;  /* 2**(.75*1) */
  }

  /* compute maximum value of distort[]  */
  trigger = 0;
  for (sfb = 0; sfb < cod_info->sfb_lmax; sfb++) {
    if (trigger < distort->l[sfb])
        trigger = distort->l[sfb];
  }
  for (sfb = cod_info->sfb_smin; sfb < SBPSY_s; sfb++) {
    for (i = 0; i < 3; i++ ) {
      if (trigger < distort->s[sfb][i])
          trigger = distort->s[sfb][i];
    }
  }

  switch (gfc->noise_shaping_amp) {

  case 2:
    /* amplify exactly 1 band */
    //trigger = distort_thresh;
    break;

  case 1:
    /* amplify bands within 50% of max (on db scale) */
    if (trigger>1.0)
        trigger = pow(trigger, .5);
    else
      trigger *= .95;
    break;

  case 0:
  default:
    /* ISO algorithm.  amplify all bands with distort>1 */
    if (trigger>1.0)
        trigger=1.0;
    else
        trigger *= .95;
    break;
  }

  for (sfb = 0; sfb < cod_info->sfb_lmax; sfb++ ) {
    start = gfc->scalefac_band.l[sfb];
    end   = gfc->scalefac_band.l[sfb+1];
    if (distort->l[sfb]>=trigger  ) {
      scalefac->l[sfb]++;
      for ( l = start; l < end; l++ )
	xrpow[l] *= ifqstep34;
      if (gfc->noise_shaping_amp==2) goto done;
    }
  }

  for ( j=0,sfb = cod_info->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++ ) {
      int j2 = j;
      if ( distort->s[sfb][i]>=trigger) {
	scalefac->s[sfb][i]++;
	for (l = start; l < end; l++)
	  xrpow[j2++] *= ifqstep34;
        if (gfc->noise_shaping_amp==2) goto done;
      }
      j += end-start;
    }
  }
 done:
 return;
}

/*************************************************************************
 *
 *      inc_scalefac_scale()
 *
 *  Takehiro Tominaga 2000-xx-xx
 *
 *  turns on scalefac scale and adjusts scalefactors
 *
 *************************************************************************/

static void
inc_scalefac_scale (
    const lame_internal_flags        * const gfc,
          gr_info        * const cod_info,
          III_scalefac_t * const scalefac,
          FLOAT8                 xrpow[576] )
{
    int start, end, l,i,j;
    int sfb;
    const FLOAT8 ifqstep34 = 1.29683955465100964055;

    for (sfb = 0; sfb < cod_info->sfb_lmax; sfb++) {
        int s = scalefac->l[sfb] + (cod_info->preflag ? pretab[sfb] : 0);
        if (s & 1) {
            s++;
            start = gfc->scalefac_band.l[sfb];
            end   = gfc->scalefac_band.l[sfb+1];
            for (l = start; l < end; l++)
                xrpow[l] *= ifqstep34;
        }
        scalefac->l[sfb]  = s >> 1;
        cod_info->preflag = 0;
    }

    for (j = 0, sfb = cod_info->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++) {
        int j2 = j;
        if (scalefac->s[sfb][i] & 1) {
        scalefac->s[sfb][i]++;
        for (l = start; l < end; l++)
            xrpow[j2++] *= ifqstep34;
        }
        scalefac->s[sfb][i] >>= 1;
        j += end-start;
    }
    }
    cod_info->scalefac_scale = 1;
}



/*************************************************************************
 *
 *      inc_subblock_gain()
 *
 *  Takehiro Tominaga 2000-xx-xx
 *
 *  increases the subblock gain and adjusts scalefactors
 *
 *************************************************************************/

static int
inc_subblock_gain (
    const lame_internal_flags        * const gfc,
          gr_info        * const cod_info,
          III_scalefac_t * const scalefac,
          FLOAT8                 xrpow[576] )
{
    int window;

    for (window = 0; window < 3; window++) {
        int s1, s2, l;
        int sfb;
        s1 = s2 = 0;

        for (sfb = cod_info->sfb_smin; sfb < 6; sfb++) {
            if (s1 < scalefac->s[sfb][window])
            s1 = scalefac->s[sfb][window];
        }
        for (; sfb < SBPSY_s; sfb++) {
            if (s2 < scalefac->s[sfb][window])
            s2 = scalefac->s[sfb][window];
        }

        if (s1 < 16 && s2 < 8)
            continue;

        if (cod_info->subblock_gain[window] >= 7)
            return 1;

        /* even though there is no scalefactor for sfb12
         * subblock gain affects upper frequencies too, that's why
         * we have to go up to SBMAX_s
         */
        cod_info->subblock_gain[window]++;
        for (sfb = cod_info->sfb_smin; sfb < SBMAX_s; sfb++) {
            int i, width;
            int s = scalefac->s[sfb][window];
            FLOAT8 amp;

            if (s < 0)
                continue;
            s = s - (4 >> cod_info->scalefac_scale);
            if (s >= 0) {
                scalefac->s[sfb][window] = s;
                continue;
            }

            scalefac->s[sfb][window] = 0;
            width = gfc->scalefac_band.s[sfb] - gfc->scalefac_band.s[sfb+1];
            i = gfc->scalefac_band.s[sfb] * 3 + width * window;
            amp = IPOW20(210 + (s << (cod_info->scalefac_scale + 1)));
            for (l = 0; l < width; l++) {
                xrpow[l] *= amp;
            }
        }
    }
    return 0;
}



/********************************************************************
 *
 *      balance_noise()
 *
 *  Takehiro Tominaga /date??
 *  Robert Hegemann 2000-09-06: made a function of it
 *
 *  amplifies scalefactor bands,
 *   - if all are already amplified returns 0
 *   - if some bands are amplified too much:
 *      * try to increase scalefac_scale
 *      * if already scalefac_scale was set
 *          try on short blocks to increase subblock gain
 *
 ********************************************************************/
inline
static int
balance_noise (
    lame_global_flags  *const gfp,
    gr_info        * const cod_info,
    III_scalefac_t * const scalefac,
    III_psy_xmin           *distort,
    FLOAT8                 xrpow[576] )
{
    lame_internal_flags *const gfc = (lame_internal_flags *)gfp->internal_flags;
    int status;

    amp_scalefac_bands ( gfp, cod_info, scalefac, distort, xrpow);

    /* check to make sure we have not amplified too much
     * loop_break returns 0 if there is an unamplified scalefac
     * scale_bitcount returns 0 if no scalefactors are too large
     */

    status = loop_break (cod_info, scalefac);

    if (status)
        return 0; /* all bands amplified */

    /* not all scalefactors have been amplified.  so these
     * scalefacs are possibly valid.  encode them:
     */
    if (gfc->is_mpeg1)
        status = scale_bitcount (scalefac, cod_info);
    else
        status = scale_bitcount_lsf (gfc, scalefac, cod_info);

    if (!status)
        return 1; /* amplified some bands not exceeding limits */

    /*  some scalefactors are too large.
     *  lets try setting scalefac_scale=1
     */
    if (gfc->noise_shaping > 1) {
	if (!cod_info->scalefac_scale) {
	    inc_scalefac_scale (gfc, cod_info, scalefac, xrpow);
	    status = 0;
	} else {
	    if (cod_info->block_type == SHORT_TYPE ) {
		status = inc_subblock_gain (gfc, cod_info, scalefac, xrpow)
		    || loop_break (cod_info, scalefac);
	    }
	}
    }

    if (!status) {
        if (gfc->is_mpeg1 == 1)
            status = scale_bitcount (scalefac, cod_info);
        else
            status = scale_bitcount_lsf (gfc, scalefac, cod_info);
    }
    return !status;
}



/************************************************************************
 *
 *  outer_loop ()
 *
 *  Function: The outer iteration loop controls the masking conditions
 *  of all scalefactorbands. It computes the best scalefac and
 *  global gain. This module calls the inner iteration loop
 *
 *  mt 5/99 completely rewritten to allow for bit reservoir control,
 *  mid/side channels with L/R or mid/side masking thresholds,
 *  and chooses best quantization instead of last quantization when
 *  no distortion free quantization can be found.
 *
 *  added VBR support mt 5/99
 *
 *  some code shuffle rh 9/00
 ************************************************************************/

static int
outer_loop (
   lame_global_flags *gfp,
          gr_info        * const cod_info,
    const FLOAT8                 xr[576],   /* magnitudes of spectral values */
    const III_psy_xmin   * const l3_xmin,   /* allowed distortion of the scalefactor */
          III_scalefac_t * const scalefac,  /* scalefactors */
          FLOAT8                 xrpow[576], /* coloured magnitudes of spectral values */
          int                    l3enc[576], /* vector of quantized values ix(0..575) */
    const int                    ch,
    const int                    targ_bits )  /* maximum allowed bits */
{
    lame_internal_flags *gfc=gfp->internal_flags;
    III_scalefac_t save_scalefac;
    gr_info save_cod_info;
    FLOAT8 save_xrpow[576];
    III_psy_xmin   distort;
    calc_noise_result noise_info;
    calc_noise_result best_noise_info;
    int l3_enc_w[576];
    int iteration = 0;
    int bits_found = 0;
    int huff_bits;
    int real_bits;
    int better;
    int over=0;

    int notdone = 1;
    int copy = 0;
    int age = 0;

    noise_info.over_count = 100;
    noise_info.tot_count  = 100;
    noise_info.max_noise  = 0;
    noise_info.tot_noise  = 0;
    noise_info.over_noise = 0;

    best_noise_info.over_count = 100;

    bits_found = bin_search_StepSize (gfc, cod_info, targ_bits,
                                      gfc->OldValue[ch], xrpow, l3_enc_w);
    gfc->OldValue[ch] = cod_info->global_gain;

    /* BEGIN MAIN LOOP */
    do {
        iteration ++;

        /* inner_loop starts with the initial quantization step computed above
         * and slowly increases until the bits < huff_bits.
         * Thus it is important not to start with too large of an inital
         * quantization step.  Too small is ok, but inner_loop will take longer
         */
        huff_bits = targ_bits - cod_info->part2_length;
        if (huff_bits < 0) {
            assert(iteration != 1);
            /*  scale factors too large, not enough bits.
             *  use previous quantizaton */
            break;
        }
        /*  if this is the first iteration,
         *  see if we can reuse the quantization computed in
         *  bin_search_StepSize above */

        if (iteration == 1) {
            if (bits_found > huff_bits) {
                cod_info->global_gain++;
                real_bits = inner_loop (gfc, cod_info, huff_bits, xrpow,
                                        l3_enc_w);
            } else {
                real_bits = bits_found;
            }
        } else {
            real_bits = inner_loop (gfc, cod_info, huff_bits, xrpow,
                                    l3_enc_w);
        }

        cod_info->part2_3_length = real_bits;

        /* compute the distortion in this quantization */
        if (gfc->noise_shaping)
            /* coefficients and thresholds both l/r (or both mid/side) */
            over = calc_noise (gfc, xr, l3_enc_w, cod_info, l3_xmin,
                               scalefac, &distort, &noise_info);
        else {
            /* fast mode, no noise shaping, we are ready */
            best_noise_info = noise_info;
            over = 0;
            copy = 0;
            memcpy(l3enc, l3_enc_w, sizeof(int)*576);
            break;
        }


        /* check if this quantization is better
         * than our saved quantization */
        if (iteration == 1) /* the first iteration is always better */
            better = 1;
        else
            better = quant_compare (gfp->experimentalX,
                                    &best_noise_info, &noise_info);

        /* save data so we can restore this quantization later */
        if (better) {
            copy = 0;
            best_noise_info = noise_info;
            memcpy(l3enc, l3_enc_w, sizeof(int)*576);
            age = 0;
        }
        else
            age ++;


        /******************************************************************/
        /* stopping criterion */
        /******************************************************************/
        /* if no bands with distortion and -X0, we are done */
        if (0==gfc->noise_shaping_stop &&
            0==gfp->experimentalX &&
	    (over == 0 || best_noise_info.over_count == 0) )
            break;
        /* Otherwise, allow up to 3 unsuccesful tries in serial, then stop
         * if our best quantization so far had no distorted bands. This
         * gives us more possibilities for different quant_compare modes.
         * Much more than 3 makes not a big difference, it is only slower.
         */
        if (age > 3 && best_noise_info.over_count == 0)
            break;





        /* Check if the last scalefactor band is distorted.
         * in VBR mode we can't get rid of the distortion, so quit now
         * and VBR mode will try again with more bits.
         * (makes a 10% speed increase, the files I tested were
         * binary identical, 2000/05/20 Robert.Hegemann@gmx.de)
         * distort[] > 1 means noise > allowed noise
         */
        if (gfc->sfb21_extra) {
            if (cod_info->block_type == SHORT_TYPE) {
                if (distort.s[SBMAX_s-1][0] > 1 ||
                    distort.s[SBMAX_s-1][1] > 1 ||
                    distort.s[SBMAX_s-1][2] > 1) break;
            } else {
                if (distort.l[SBMAX_l-1] > 1) break;
            }
        }

        /* save data so we can restore this quantization later */
        if (better) {
            copy = 1;
            save_scalefac = *scalefac;
            save_cod_info = *cod_info;
            if (gfp->VBR == vbr_rh || gfp->VBR == vbr_mtrh) {
                /* store for later reuse */
                memcpy(save_xrpow, xrpow, sizeof(FLOAT8)*576);
            }
        }

        notdone = balance_noise (gfp, cod_info, scalefac, &distort, xrpow);

        if (notdone == 0)
            break;
    }
    while (1); /* main iteration loop, breaks adjusted */

    /*  finish up
     */
    if (copy) {
        *cod_info = save_cod_info;
        *scalefac = save_scalefac;
        if (gfp->VBR == vbr_rh || gfp->VBR == vbr_mtrh)
            /* restore for reuse on next try */
            memcpy(xrpow, save_xrpow, sizeof(FLOAT8)*576);
    }
    cod_info->part2_3_length += cod_info->part2_length;

    assert (cod_info->global_gain < 256);

    return best_noise_info.over_count;
}




/************************************************************************
 *
 *      iteration_finish()
 *
 *  Robert Hegemann 2000-09-06
 *
 *  update reservoir status after FINAL quantization/bitrate
 *
 *  rh 2000-09-06: it will not work with CBR due to the bitstream formatter
 *            you will get "Error: MAX_HEADER_BUF too small in bitstream.c"
 *
 ************************************************************************/

static void
iteration_finish (
    lame_internal_flags *gfc,
    FLOAT8          xr      [2][2][576],
    int             l3_enc  [2][2][576],
    III_psy_ratio   ratio   [2][2],
    III_scalefac_t  scalefac[2][2],
    const int       mean_bits )
{
    III_side_info_t *l3_side = &gfc->l3_side;
    int gr, ch, i;

    for (gr = 0; gr < gfc->mode_gr; gr++) {
        for (ch = 0; ch < gfc->channels_out; ch++) {
            gr_info *cod_info = &l3_side->gr[gr].ch[ch].tt;

            /*  try some better scalefac storage
             */
            best_scalefac_store (gfc, gr, ch, l3_enc, l3_side, scalefac);

            /*  best huffman_divide may save some bits too
             */
            if (gfc->use_best_huffman == 1)
                best_huffman_divide (gfc, gr, ch, cod_info, l3_enc[gr][ch]);

            /*  update reservoir status after FINAL quantization/bitrate
             */
            ResvAdjust (gfc, cod_info, l3_side, mean_bits);

            /*  set the sign of l3_enc from the sign of xr
             */
            for (i = 0; i < 576; i++) {
                if (xr[gr][ch][i] < 0) l3_enc[gr][ch][i] *= -1;
            }
        } /* for ch */
    }    /* for gr */

    ResvFrameEnd (gfc, l3_side, mean_bits);
}



/*********************************************************************
 *
 *      VBR_encode_granule()
 *
 *  2000-09-04 Robert Hegemann
 *
 *********************************************************************/

static void
VBR_encode_granule (
          lame_global_flags *gfp,
          gr_info        * const cod_info,
          FLOAT8                 xr[576],     /* magnitudes of spectral values */
    const III_psy_xmin   * const l3_xmin,     /* allowed distortion of the scalefactor */
          III_scalefac_t * const scalefac,    /* scalefactors */
          FLOAT8                 xrpow[576],  /* coloured magnitudes of spectral values */
          int                    l3_enc[576], /* vector of quantized values ix(0..575) */
    const int                    ch,
          int                    min_bits,
          int                    max_bits )
{
    //lame_internal_flags *gfc=gfp->internal_flags;
    gr_info         bst_cod_info;
    III_scalefac_t  bst_scalefac;
    FLOAT8          bst_xrpow [576];
    int             bst_l3_enc[576];
    int Max_bits  = max_bits;
    int real_bits = max_bits+1;
    int this_bits = min_bits+(max_bits-min_bits)/2;
    int dbits, over;

    assert(Max_bits <= MAX_BITS);

    bst_cod_info = *cod_info;
    memset(&bst_scalefac, 0, sizeof(III_scalefac_t));
    memcpy(&bst_xrpow, xrpow, sizeof(FLOAT8)*576);

    /*  search within round about 40 bits of optimal
     */
    do {
        assert(this_bits >= min_bits);
        assert(this_bits <= max_bits);

        over = outer_loop ( gfp, cod_info, xr, l3_xmin, scalefac,
                            xrpow, l3_enc, ch, this_bits );

        /*  is quantization as good as we are looking for ?
         *  in this case: is no scalefactor band distorted?
         */
        if (over <= 0) {
            /*  now we know it can be done with "real_bits"
             *  and maybe we can skip some iterations
             */
            real_bits = cod_info->part2_3_length;

            /*  store best quantization so far
             */
            bst_cod_info = *cod_info;
            bst_scalefac = *scalefac;
            memcpy(bst_xrpow, xrpow, sizeof(FLOAT8)*576);
            memcpy(bst_l3_enc, l3_enc, sizeof(int)*576);

            /*  try with fewer bits
             */
            max_bits  = real_bits-32;
            dbits     = max_bits-min_bits;
            this_bits = min_bits+dbits/2;
        }
        else {
            /*  try with more bits
             */
            min_bits  = this_bits+32;
            dbits     = max_bits-min_bits;
            this_bits = min_bits+dbits/2;

            if (dbits>8) {
                /*  start again with best quantization so far
                 */
                *cod_info = bst_cod_info;
                *scalefac = bst_scalefac;
                memcpy(xrpow, bst_xrpow, sizeof(FLOAT8)*576);
            }
        }
    } while (dbits>8);

    if (real_bits <= Max_bits) {
        /*  restore best quantization found
         */
        *cod_info = bst_cod_info;
        *scalefac = bst_scalefac;
        memcpy(l3_enc, bst_l3_enc, sizeof(int)*576);
    }
    assert(cod_info->part2_3_length <= Max_bits);
}



/************************************************************************
 *
 *      get_framebits()
 *
 *  Robert Hegemann 2000-09-05
 *
 *  calculates
 *  * how many bits are available for analog silent granules
 *  * how many bits to use for the lowest allowed bitrate
 *  * how many bits each bitrate would provide
 *
 ************************************************************************/

static void
get_framebits (
    lame_global_flags *gfp,
    int     * const analog_mean_bits,
    int     * const min_mean_bits,
    int             frameBits[15] )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    int bitsPerFrame, mean_bits, i;
    III_side_info_t *l3_side = &gfc->l3_side;

    /*  always use at least this many bits per granule per channel
     *  unless we detect analog silence, see below
     */
    gfc->bitrate_index = gfc->VBR_min_bitrate;
    getframebits (gfp, &bitsPerFrame, &mean_bits);
    *min_mean_bits = mean_bits / gfc->channels_out;

    /*  bits for analog silence
     */
    gfc->bitrate_index = 1;
    getframebits (gfp, &bitsPerFrame, &mean_bits);
    *analog_mean_bits = mean_bits / gfc->channels_out;

    for (i = 1; i <= gfc->VBR_max_bitrate; i++) {
        gfc->bitrate_index = i;
        getframebits (gfp, &bitsPerFrame, &mean_bits);
        frameBits[i] = ResvFrameBegin (gfp, l3_side, mean_bits, bitsPerFrame);
    }
}



/************************************************************************
 *
 *      calc_min_bits()
 *
 *  Robert Hegemann 2000-09-04
 *
 *  determine minimal bit skeleton
 *
 ************************************************************************/
inline
static int
calc_min_bits (
    lame_global_flags *gfp,
    const gr_info * const cod_info,
    const int             pe,
    const FLOAT8          ms_ener_ratio,
    const int             bands,
    const int             mch_bits,
    const int             analog_mean_bits,
    const int             min_mean_bits,
    const int             analog_silence,
    const int             ch )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    int min_bits, min_pe_bits;

    if (gfc->nsPsy.use) return 1;

    /*  base amount of minimum bits
     */
    min_bits = Max (125, min_mean_bits);

    if (gfc->mode_ext == MPG_MD_MS_LR && ch == 1)
        min_bits = Max (min_bits, mch_bits/5);

    /*  bit skeleton based on PE
     */
    if (cod_info->block_type == SHORT_TYPE)
        /*  if LAME switches to short blocks then pe is
         *  >= 1000 on medium surge
         *  >= 3000 on big surge
         */
        min_pe_bits = (pe-350) * bands/39;
    else
        min_pe_bits = (pe-350) * bands/22;

    if (gfc->mode_ext == MPG_MD_MS_LR && ch == 1) {
        /*  side channel will use a lower bit skeleton based on PE
         */
        FLOAT8 fac  = .33 * (.5 - ms_ener_ratio) / .5;
        min_pe_bits = (int)(min_pe_bits * ((1-fac)/(1+fac)));
    }
    min_pe_bits = Min (min_pe_bits, (1820 * gfp->out_samplerate / 44100));

    /*  determine final minimum bits
     */
    if (analog_silence && !gfp->VBR_hard_min)
        min_bits = analog_mean_bits;
    else
        min_bits = Max (min_bits, min_pe_bits);

    return min_bits;
}



/************************************************************************
 *
 *      calc_max_bits()
 *
 *  Robert Hegemann 2000-09-05
 *
 *  determine maximal bit skeleton
 *
 ************************************************************************/
inline
static int
calc_max_bits (
    const lame_internal_flags * const gfc,
    const int             frameBits[15],
    const int             min_bits )
{
    int max_bits;

    max_bits  = frameBits[gfc->VBR_max_bitrate];
    max_bits /= gfc->channels_out * gfc->mode_gr;
    max_bits  = Min (1200 + max_bits, MAX_BITS - 195 * (gfc->channels_out - 1));
    max_bits  = Max (max_bits, min_bits);

    return max_bits;
}



/*********************************************************************
 *
 *      VBR_prepare()
 *
 *  2000-09-04 Robert Hegemann
 *
 *  * converts LR to MS coding when necessary
 *  * calculates allowed/adjusted quantization noise amounts
 *  * detects analog silent frames
 *
 *  some remarks:
 *  - lower masking depending on Quality setting
 *  - quality control together with adjusted ATH MDCT scaling
 *    on lower quality setting allocate more noise from
 *    ATH masking, and on higher quality setting allocate
 *    less noise from ATH masking.
 *  - experiments show that going more than 2dB over GPSYCHO's
 *    limits ends up in very annoying artefacts
 *
 *********************************************************************/

/* RH: this one needs to be overhauled sometime */

static int
VBR_prepare (
          lame_global_flags *gfp,
          FLOAT8          pe            [2][2],
          FLOAT8          ms_ener_ratio [2],
          FLOAT8          xr            [2][2][576],
          III_psy_ratio   ratio         [2][2],
          III_psy_xmin    l3_xmin       [2][2],
          int             frameBits     [16],
          int            *analog_mean_bits,
          int            *min_mean_bits,
          int             min_bits      [2][2],
          int             max_bits      [2][2],
          int             bands         [2][2] )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    static const FLOAT8 dbQ[10]={-2.,-1.0,-.66,-.33,0.,0.33,.66,1.0,1.33,1.66};
    static const FLOAT8 dbQns[10]={- 4,- 3,-2,-1,0,0.7,1.4,2.1,2.8,3.5};
    /*static const FLOAT8 atQns[10]={-16,-12,-8,-4,0,  1,  2,  3,  4,  5};*/

    static const FLOAT8 dbQmtrh[10]=
        { -4., -3., -2., -1., 0., 0.5, 1., 1.5, 2., 2.5 };

    FLOAT8   masking_lower_db, adjust = 0.0;
    int      gr, ch;
    int      used_bits = 0, bits;
    int      analog_silence = 1;

    assert( gfp->VBR_q <= 9 );
    assert( gfp->VBR_q >= 0 );

    get_framebits (gfp, analog_mean_bits, min_mean_bits, frameBits);

    for (gr = 0; gr < gfc->mode_gr; gr++) {
        if (gfc->mode_ext == MPG_MD_MS_LR)
            ms_convert (xr[gr], xr[gr]);

        for (ch = 0; ch < gfc->channels_out; ch++) {
            gr_info *cod_info = &gfc->l3_side.gr[gr].ch[ch].tt;

            if (cod_info->block_type == SHORT_TYPE)
                adjust = 5/(1+exp(3.5-pe[gr][ch]/300.))-0.14;
            else
                adjust = 2/(1+exp(3.5-pe[gr][ch]/300.))-0.05;

	    if (vbr_mtrh == gfp->VBR) {
	        masking_lower_db   = dbQmtrh[gfp->VBR_q] - adjust;
            }
            else if (gfc->nsPsy.use && gfp->ATHtype == 0) {
	        masking_lower_db   = dbQns[gfp->VBR_q] - adjust;
	    }
            else {
	        masking_lower_db   = dbQ[gfp->VBR_q] - adjust;
	    }
            gfc->masking_lower = pow (10.0, masking_lower_db * 0.1);

            bands[gr][ch] = calc_xmin (gfp, xr[gr][ch], ratio[gr]+ch,
                                       cod_info, l3_xmin[gr]+ch);
            if (bands[gr][ch])
                analog_silence = 0;


            min_bits[gr][ch] = calc_min_bits (gfp, cod_info, (int)pe[gr][ch],
                                      ms_ener_ratio[gr], bands[gr][ch],
                                      0, *analog_mean_bits,
                                      *min_mean_bits, analog_silence, ch);

            max_bits[gr][ch] = calc_max_bits (gfc, frameBits, min_bits[gr][ch]);
            used_bits += min_bits[gr][ch];

        } /* for ch */
    }  /* for gr */

    *min_mean_bits = Max(125, *min_mean_bits);
    bits = 0.8*frameBits[gfc->VBR_max_bitrate];
    if (used_bits >= bits)
        for (gr = 0; gr < gfc->mode_gr; gr++) {
            for (ch = 0; ch < gfc->channels_out; ch++) {
                min_bits[gr][ch] *= bits;
                min_bits[gr][ch] /= used_bits;
                if (min_bits[gr][ch] < *min_mean_bits)
                    min_bits[gr][ch] = *min_mean_bits;
                max_bits[gr][ch] *= bits;
                max_bits[gr][ch] /= used_bits;
                if (max_bits[gr][ch] < *min_mean_bits)
                    max_bits[gr][ch] = *min_mean_bits;
            }
        }


    return analog_silence;
}



/************************************************************************
 *
 *      VBR_iteration_loop()
 *
 *  tries to find out how many bits are needed for each granule and channel
 *  to get an acceptable quantization. An appropriate bitrate will then be
 *  choosed for quantization.  rh 8/99
 *
 *  Robert Hegemann 2000-09-06 rewrite
 *
 ************************************************************************/

void
VBR_iteration_loop (
    lame_global_flags *gfp,
    FLOAT8             pe           [2][2],
    FLOAT8             ms_ener_ratio[2],
    FLOAT8             xr           [2][2][576],
    III_psy_ratio      ratio        [2][2],
    int                l3_enc       [2][2][576],
    III_scalefac_t     scalefac     [2][2] )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    III_psy_xmin l3_xmin[2][2];

    FLOAT8    xrpow[576];
    int       bands[2][2];
    int       frameBits[15];
    int       bitsPerFrame;
    int       save_bits[2][2];
    int       used_bits, used_bits2;
    int       bits;
    int       min_bits[2][2], max_bits[2][2];
    int       analog_mean_bits, min_mean_bits;
    int       mean_bits;
    int       ch, num_chan, gr, analog_silence;
    int       reduce_s_ch, sfb21_extra;
    gr_info             *cod_info;
    III_side_info_t     *l3_side  = &gfc->l3_side;

    if (gfc->mode_ext == MPG_MD_MS_LR && gfp->quality >= 5) {
        /*  my experiences are, that side channel reduction
         *  does more harm than good when VBR encoding
         *  (Robert.Hegemann@gmx.de 2000-02-18)
         *  2000-09-06: code is enabled at quality level 5
         */
        reduce_s_ch = 1;
        num_chan    = 1;
    } else {
        reduce_s_ch = 0;
        num_chan    = gfc->channels_out;
    }

    analog_silence = VBR_prepare (gfp, pe, ms_ener_ratio, xr, ratio,
                                  l3_xmin, frameBits, &analog_mean_bits,
                                  &min_mean_bits, min_bits, max_bits, bands);

    /*---------------------------------*/
    do {

    /*  quantize granules with lowest possible number of bits
     */

    used_bits = 0;
    used_bits2 = 0;

    for (gr = 0; gr < gfc->mode_gr; gr++) {
        for (ch = 0; ch < num_chan; ch++) {
            int ret;
            cod_info = &l3_side->gr[gr].ch[ch].tt;

            /*  init_outer_loop sets up cod_info, scalefac and xrpow
             */
            ret = init_outer_loop(cod_info, &scalefac[gr][ch], gfc->is_mpeg1,
				  xr[gr][ch], xrpow);
            if (ret == 0) {
                /*  xr contains no energy
                 *  l3_enc, our encoding data, will be quantized to zero
                 */
                memset(l3_enc[gr][ch], 0, sizeof(int)*576);
                save_bits[gr][ch] = 0;
                continue; /* with next channel */
            }
#if 0
            if (gfc->mode_ext == MPG_MD_MS_LR && ch == 1)
                min_bits[gr][ch] = Max (min_bits[gr][ch], save_bits[gr][0]/5);
#endif

            if (gfp->VBR == vbr_mtrh) {
                ret = VBR_noise_shaping2 (gfp, xr[gr][ch], xrpow,
                                        &ratio[gr][ch], l3_enc[gr][ch], 0,
                                        min_bits[gr][ch], max_bits[gr][ch],
                                        &scalefac[gr][ch],
                                        &l3_xmin[gr][ch], gr, ch );
                if (ret < 0)
                    cod_info->part2_3_length = 100000;
            }
            else
                VBR_encode_granule (gfp, cod_info, xr[gr][ch], &l3_xmin[gr][ch],
                                    &scalefac[gr][ch], xrpow, l3_enc[gr][ch],
                                    ch, min_bits[gr][ch], max_bits[gr][ch] );

            used_bits += cod_info->part2_3_length;
            save_bits[gr][ch] = Min(MAX_BITS, cod_info->part2_3_length);
            used_bits2 += Min(MAX_BITS, cod_info->part2_3_length);
        } /* for ch */
    }    /* for gr */

    /*  special on quality=5, we didn't quantize side channel above
     */
    if (reduce_s_ch) {
        /*  number of bits needed was found for MID channel above.  Use formula
         *  (fixed bitrate code) to set the side channel bits */
        for (gr = 0; gr < gfc->mode_gr; gr++) {
            FLOAT8 fac = .33*(.5-ms_ener_ratio[gr])/.5;
            save_bits[gr][1] = (int)(((1-fac)/(1+fac)) * save_bits[gr][0]);
            save_bits[gr][1] = Max (analog_mean_bits, save_bits[gr][1]);
            used_bits += save_bits[gr][1];
        }
    }

    /*  find lowest bitrate able to hold used bits
     */
    if (analog_silence && !gfp->VBR_hard_min)
        /*  we detected analog silence and the user did not specify
         *  any hard framesize limit, so start with smallest possible frame
         */
        gfc->bitrate_index = 1;
    else
        gfc->bitrate_index = gfc->VBR_min_bitrate;

    for( ; gfc->bitrate_index < gfc->VBR_max_bitrate; gfc->bitrate_index++) {
        if (used_bits <= frameBits[gfc->bitrate_index]) break;
    }

    getframebits (gfp, &bitsPerFrame, &mean_bits);
    bits = ResvFrameBegin (gfp, l3_side, mean_bits, bitsPerFrame);

    if (used_bits > bits){
        //printf("# %d used %d have %d\n",gfp->frameNum,used_bits,bits);
        if(gfp->VBR == vbr_mtrh) {
            for (gr = 0; gr < gfc->mode_gr; gr++) {
                for (ch = 0; ch < gfc->channels_out; ch++) {
                    max_bits[gr][ch] = save_bits[gr][ch];
                    max_bits[gr][ch] *= frameBits[gfc->bitrate_index];
                    max_bits[gr][ch] /= used_bits2;
                    max_bits[gr][ch] = Max(min_bits[gr][ch],max_bits[gr][ch]);
                }
            }
        }
        else {
            for (gr = 0; gr < gfc->mode_gr; gr++) {
                for (ch = 0; ch < gfc->channels_out; ch++) {
                    int sfb;
                    cod_info = &l3_side->gr[gr].ch[ch].tt;
                    if (cod_info->block_type == SHORT_TYPE) {
                        for (sfb = 0; sfb < SBMAX_s; sfb++) {
                            l3_xmin[gr][ch].s[sfb][0] *= 1.+.029*sfb*sfb/SBMAX_s/SBMAX_s;
                            l3_xmin[gr][ch].s[sfb][1] *= 1.+.029*sfb*sfb/SBMAX_s/SBMAX_s;
                            l3_xmin[gr][ch].s[sfb][2] *= 1.+.029*sfb*sfb/SBMAX_s/SBMAX_s;
                        }
                    }
                    else {
                        for (sfb = 0; sfb < SBMAX_l; sfb++)
                            l3_xmin[gr][ch].l[sfb] *= 1.+.029*sfb*sfb/SBMAX_l/SBMAX_l;
                    }
//                  min_bits[gr][ch] = Max(min_mean_bits, 0.9*min_bits[gr][ch]);
                    max_bits[gr][ch] = Max(min_mean_bits, 0.9*max_bits[gr][ch]);
                }
            }
        }
    }

    } while (used_bits > bits);
    /*--------------------------------------*/

    /*  ignore sfb21 by the following (maybe) noise shaping
     */
    sfb21_extra = gfc->sfb21_extra;
    gfc->sfb21_extra = 0;

    /*  quantize granules which violate bit constraints again
     *  and side channel when in quality=5 reduce_side is used
     */
    for (gr = 0; gr < gfc->mode_gr; gr++) {
        for (ch = 0; ch < gfc->channels_out; ch++) {
            int ret;
            cod_info = &l3_side->gr[gr].ch[ch].tt;

            if (used_bits <= bits && ! (reduce_s_ch && ch == 1))
                /*  we have enough bits
                 *  and have already encoded the side channel
                 */
                continue; /* with next ch */

            if (used_bits > bits) {
                /*  repartion available bits in same proportion
                 */
                save_bits[gr][ch] *= frameBits[gfc->bitrate_index];
                save_bits[gr][ch] /= used_bits;
            }
            /*  init_outer_loop sets up cod_info, scalefac and xrpow
             */
            ret = init_outer_loop(cod_info, &scalefac[gr][ch], gfc->is_mpeg1,
				  xr[gr][ch], xrpow);
            if (ret == 0)
            {
                /*  xr contains no energy
                 *  l3_enc, our encoding data, will be quantized to zero
                 */
                memset(l3_enc[gr][ch], 0, sizeof(int)*576);
            }
            else {
                /*  xr contains energy we will have to encode
                 *  masking abilities were previously calculated
                 *  find some good quantization in outer_loop
                 */
                outer_loop (gfp, cod_info, xr[gr][ch], &l3_xmin[gr][ch],
                            &scalefac[gr][ch], xrpow, l3_enc[gr][ch], ch,
                            save_bits[gr][ch]);
            }
        } /* ch */
    }  /* gr */

    gfc->sfb21_extra = sfb21_extra;

    iteration_finish (gfc, xr, l3_enc, ratio, scalefac, mean_bits);
}






/********************************************************************
 *
 *  calc_target_bits()
 *
 *  calculates target bits for ABR encoding
 *
 *  mt 2000/05/31
 *
 ********************************************************************/

static void
calc_target_bits (
    lame_global_flags * gfp,
    FLOAT8               pe            [2][2],
    FLOAT8               ms_ener_ratio [2],
    int                  targ_bits     [2][2],
    int                 *analog_silence_bits,
    int                 *max_frame_bits )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    III_side_info_t *l3_side = &gfc->l3_side;
    FLOAT8 res_factor;
    int gr, ch, totbits, mean_bits, bitsPerFrame;

    gfc->bitrate_index = gfc->VBR_max_bitrate;
    getframebits (gfp, &bitsPerFrame, &mean_bits);
    *max_frame_bits = ResvFrameBegin (gfp, l3_side, mean_bits, bitsPerFrame);

    gfc->bitrate_index = 1;
    getframebits (gfp, &bitsPerFrame, &mean_bits);
    *analog_silence_bits = mean_bits / gfc->channels_out;

    mean_bits  = gfp->VBR_mean_bitrate_kbps * gfp->framesize * 1000;
    mean_bits /= gfp->out_samplerate;
    mean_bits -= gfc->sideinfo_len*8;
    mean_bits /= gfc->mode_gr;

    res_factor = .90 + .10 * (11.0 - gfp->compression_ratio) / (11.0 - 5.5);
    if (res_factor <  .90)
        res_factor =  .90;
    if (res_factor > 1.00)
        res_factor = 1.00;

    for (gr = 0; gr < gfc->mode_gr; gr++) {
        for (ch = 0; ch < gfc->channels_out; ch++) {
            targ_bits[gr][ch] = res_factor * (mean_bits / gfc->channels_out);

            if (pe[gr][ch] > 700) {
                int add_bits = (pe[gr][ch] - 700) / 1.4;

                gr_info *cod_info = &l3_side->gr[gr].ch[ch].tt;
                targ_bits[gr][ch] = res_factor * (mean_bits / gfc->channels_out);

                /* short blocks use a little extra, no matter what the pe */
                if (cod_info->block_type == SHORT_TYPE) {
                    if (add_bits < mean_bits/4)
                        add_bits = mean_bits/4;
                }
                /* at most increase bits by 1.5*average */
                if (add_bits > mean_bits*3/4)
                    add_bits = mean_bits*3/4;
                else
                if (add_bits < 0)
                    add_bits = 0;

                targ_bits[gr][ch] += add_bits;
            }
        }/* for ch */
    }   /* for gr */

    if (gfc->mode_ext == MPG_MD_MS_LR)
        for (gr = 0; gr < gfc->mode_gr; gr++) {
            reduce_side (targ_bits[gr], ms_ener_ratio[gr], mean_bits,
			 MAX_BITS);
        }

    /*  sum target bits
     */
    totbits=0;
    for (gr = 0; gr < gfc->mode_gr; gr++) {
        for (ch = 0; ch < gfc->channels_out; ch++) {
            if (targ_bits[gr][ch] > MAX_BITS)
                targ_bits[gr][ch] = MAX_BITS;
            totbits += targ_bits[gr][ch];
        }
    }

    /*  repartion target bits if needed
     */
    if (totbits > *max_frame_bits) {
        for(gr = 0; gr < gfc->mode_gr; gr++) {
            for(ch = 0; ch < gfc->channels_out; ch++) {
                targ_bits[gr][ch] *= *max_frame_bits;
                targ_bits[gr][ch] /= totbits;
            }
        }
    }
}






/********************************************************************
 *
 *  ABR_iteration_loop()
 *
 *  encode a frame with a disired average bitrate
 *
 *  mt 2000/05/31
 *
 ********************************************************************/

void
ABR_iteration_loop(
    lame_global_flags *gfp,
    FLOAT8             pe           [2][2],
    FLOAT8             ms_ener_ratio[2],
    FLOAT8             xr           [2][2][576],
    III_psy_ratio      ratio        [2][2],
    int                l3_enc       [2][2][576],
    III_scalefac_t     scalefac     [2][2] )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    III_psy_xmin l3_xmin;
    FLOAT8    xrpow[576];
    int       targ_bits[2][2];
    int       bitsPerFrame, mean_bits, totbits, max_frame_bits;
    int       ch, gr, ath_over, ret;
    int       analog_silence_bits;
    gr_info             *cod_info = NULL;
    III_side_info_t     *l3_side  = &gfc->l3_side;

    calc_target_bits (gfp, pe, ms_ener_ratio, targ_bits,
                      &analog_silence_bits, &max_frame_bits);

    /*  encode granules
     */
    totbits=0;
    for (gr = 0; gr < gfc->mode_gr; gr++) {

        if (gfc->mode_ext == MPG_MD_MS_LR)
            ms_convert (xr[gr], xr[gr]);

        for (ch = 0; ch < gfc->channels_out; ch++) {
            cod_info = &l3_side->gr[gr].ch[ch].tt;

            /*  cod_info, scalefac and xrpow get initialized in init_outer_loop
             */
            ret = init_outer_loop(cod_info, &scalefac[gr][ch], gfc->is_mpeg1,
				  xr[gr][ch], xrpow);
            if (ret == 0) {
                /*  xr contains no energy
                 *  l3_enc, our encoding data, will be quantized to zero
                 */
                memset(l3_enc[gr][ch], 0, sizeof(int)*576);
            }
            else {
                /*  xr contains energy we will have to encode
                 *  calculate the masking abilities
                 *  find some good quantization in outer_loop
                 */
                ath_over = calc_xmin (gfp, xr[gr][ch], &ratio[gr][ch],
                                      cod_info, &l3_xmin);
                if (0 == ath_over) /* analog silence */
                    targ_bits[gr][ch] = analog_silence_bits;

                outer_loop (gfp, cod_info, xr[gr][ch], &l3_xmin,
                            &scalefac[gr][ch], xrpow, l3_enc[gr][ch],
                            ch, targ_bits[gr][ch]);
            }

            totbits += cod_info->part2_3_length;
        } /* ch */
    }  /* gr */

    /*  find a bitrate which can handle totbits
     */
    for (gfc->bitrate_index =  gfc->VBR_min_bitrate ;
         gfc->bitrate_index <= gfc->VBR_max_bitrate;
         gfc->bitrate_index++    ) {
        getframebits (gfp, &bitsPerFrame, &mean_bits);
        max_frame_bits = ResvFrameBegin (gfp, l3_side, mean_bits, bitsPerFrame);
        if (totbits <= max_frame_bits) break;
    }
    assert (gfc->bitrate_index <= gfc->VBR_max_bitrate);

    iteration_finish (gfc, xr, l3_enc, ratio, scalefac, mean_bits);
}






/************************************************************************
 *
 *      iteration_loop()
 *
 *  author/date??
 *
 *  encodes one frame of MP3 data with constant bitrate
 *
 ************************************************************************/

void
iteration_loop(
    lame_global_flags *gfp,
    FLOAT8             pe           [2][2],
    FLOAT8             ms_ener_ratio[2],
    FLOAT8             xr           [2][2][576],
    III_psy_ratio      ratio        [2][2],
    int                l3_enc       [2][2][576],
    III_scalefac_t     scalefac     [2][2] )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    III_psy_xmin l3_xmin[2];
    FLOAT8 xrpow[576];
    int    targ_bits[2];
    int    bitsPerFrame;
    int    mean_bits, max_bits, bit_rate;
    int    gr, ch, i;
    III_side_info_t     *l3_side = &gfc->l3_side;
    gr_info             *cod_info;

    bit_rate = bitrate_table [gfp->version] [gfc->bitrate_index];
    getframebits (gfp, &bitsPerFrame, &mean_bits);
    ResvFrameBegin (gfp, l3_side, mean_bits, bitsPerFrame );

    /* quantize! */
    for (gr = 0; gr < gfc->mode_gr; gr++) {

        /*  calculate needed bits
         */
        max_bits = on_pe (gfp, pe, l3_side, targ_bits, mean_bits, gr);

        if (gfc->mode_ext == MPG_MD_MS_LR) {
            ms_convert (xr[gr], xr[gr]);
            reduce_side (targ_bits, ms_ener_ratio[gr], mean_bits, max_bits);
        }

        for (ch=0 ; ch < gfc->channels_out ; ch ++) {
            cod_info = &l3_side->gr[gr].ch[ch].tt;

            /*  init_outer_loop sets up cod_info, scalefac and xrpow
             */
            i = init_outer_loop(cod_info, &scalefac[gr][ch], gfc->is_mpeg1,
				xr[gr][ch], xrpow);
            if (i == 0) {
                /*  xr contains no energy, l3_enc will be quantized to zero
                 */
                memset(l3_enc[gr][ch], 0, sizeof(int)*576);
            }
            else {
                /*  xr contains energy we will have to encode
                 *  calculate the masking abilities
                 *  find some good quantization in outer_loop
                 */
                calc_xmin (gfp, xr[gr][ch], &ratio[gr][ch], cod_info,
                           &l3_xmin[ch]);
                outer_loop (gfp, cod_info, xr[gr][ch], &l3_xmin[ch],
                            &scalefac[gr][ch], xrpow, l3_enc[gr][ch],
                            ch, targ_bits[ch]);
            }
            assert (cod_info->part2_3_length <= MAX_BITS);

            /*  try some better scalefac storage
             */
            best_scalefac_store (gfc, gr, ch, l3_enc, l3_side, scalefac);

            /*  best huffman_divide may save some bits too
             */
            if (gfc->use_best_huffman == 1)
                best_huffman_divide (gfc, gr, ch, cod_info, l3_enc[gr][ch]);

            /*  update reservoir status after FINAL quantization/bitrate
             */
#undef  NORES_TEST
#ifndef NORES_TEST
            ResvAdjust (gfc, cod_info, l3_side, mean_bits);
#endif
            /*  set the sign of l3_enc from the sign of xr
             */
            for (i = 0; i < 576; i++) {
                if (xr[gr][ch][i] < 0) l3_enc[gr][ch][i] *= -1;
            }
        } /* for ch */
    }    /* for gr */

#ifdef NORES_TEST
    /* replace ResvAdjust above with this code if you do not want
       the second granule to use bits saved by the first granule.
       Requires using the --nores.  This is useful for testing only */
    for (gr = 0; gr < gfc->mode_gr; gr++) {
        for (ch =  0; ch < gfc->channels_out; ch++) {
            cod_info = &l3_side->gr[gr].ch[ch].tt;
            ResvAdjust (gfc, cod_info, l3_side, mean_bits);
        }
    }
#endif

    ResvFrameEnd (gfc, l3_side, mean_bits);
}