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FFmpeg/libavcodec/aaccoder.c

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  1. /*

  2.  * AAC coefficients encoder

  3.  * Copyright (C) 2008-2009 Konstantin Shishkov

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

  7.  * FFmpeg is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * FFmpeg is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with FFmpeg; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * AAC coefficients encoder

  25.  */

  26. 

  27. /***********************************

  28.  *              TODOs:

  29.  * speedup quantizer selection

  30.  * add sane pulse detection

  31.  ***********************************/

  32. 

  33. #include "libavutil/libm.h" // brought forward to work around cygwin header breakage

  34. 

  35. #include <float.h>

  36. #include "libavutil/mathematics.h"

  37. #include "avcodec.h"

  38. #include "put_bits.h"

  39. #include "aac.h"

  40. #include "aacenc.h"

  41. #include "aactab.h"

  42. #include "aacenctab.h"

  43. #include "aacenc_utils.h"

  44. #include "aacenc_quantization.h"

  45. #include "aac_tablegen_decl.h"

  46. 

  47. #include "aacenc_is.h"

  48. 

  49. /** Frequency in Hz for lower limit of noise substitution **/

  50. #define NOISE_LOW_LIMIT 4500

  51. 

  52. /* Energy spread threshold value below which no PNS is used, this corresponds to

  53.  * typically around 17Khz, after which PNS usage decays ending at 19Khz */

  54. #define NOISE_SPREAD_THRESHOLD 0.5f

  55. 

  56. /* This constant gets divided by lambda to return ~1.65 which when multiplied

  57.  * by the band->threshold and compared to band->energy is the boundary between

  58.  * excessive PNS and little PNS usage. */

  59. #define NOISE_LAMBDA_NUMERATOR 252.1f

  60. 

  61. /**

  62.  * structure used in optimal codebook search

  63.  */

  64. typedef struct BandCodingPath {

  65.     int prev_idx; ///< pointer to the previous path point

  66.     float cost;   ///< path cost

  67.     int run;

  68. } BandCodingPath;

  69. 

  70. /**

  71.  * Encode band info for single window group bands.

  72.  */

  73. static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,

  74.                                      int win, int group_len, const float lambda)

  75. {

  76.     BandCodingPath path[120][CB_TOT_ALL];

  77.     int w, swb, cb, start, size;

  78.     int i, j;

  79.     const int max_sfb  = sce->ics.max_sfb;

  80.     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;

  81.     const int run_esc  = (1 << run_bits) - 1;

  82.     int idx, ppos, count;

  83.     int stackrun[120], stackcb[120], stack_len;

  84.     float next_minrd = INFINITY;

  85.     int next_mincb = 0;

  86. 

  87.     abs_pow34_v(s->scoefs, sce->coeffs, 1024);

  88.     start = win*128;

  89.     for (cb = 0; cb < CB_TOT_ALL; cb++) {

  90.         path[0][cb].cost     = 0.0f;

  91.         path[0][cb].prev_idx = -1;

  92.         path[0][cb].run      = 0;

  93.     }

  94.     for (swb = 0; swb < max_sfb; swb++) {

  95.         size = sce->ics.swb_sizes[swb];

  96.         if (sce->zeroes[win*16 + swb]) {

  97.             for (cb = 0; cb < CB_TOT_ALL; cb++) {

  98.                 path[swb+1][cb].prev_idx = cb;

  99.                 path[swb+1][cb].cost     = path[swb][cb].cost;

  100.                 path[swb+1][cb].run      = path[swb][cb].run + 1;

  101.             }

  102.         } else {

  103.             float minrd = next_minrd;

  104.             int mincb = next_mincb;

  105.             next_minrd = INFINITY;

  106.             next_mincb = 0;

  107.             for (cb = 0; cb < CB_TOT_ALL; cb++) {

  108.                 float cost_stay_here, cost_get_here;

  109.                 float rd = 0.0f;

  110.                 if (cb >= 12 && sce->band_type[win*16+swb] < aac_cb_out_map[cb] ||

  111.                     cb  < aac_cb_in_map[sce->band_type[win*16+swb]] && sce->band_type[win*16+swb] > aac_cb_out_map[cb]) {

  112.                     path[swb+1][cb].prev_idx = -1;

  113.                     path[swb+1][cb].cost     = INFINITY;

  114.                     path[swb+1][cb].run      = path[swb][cb].run + 1;

  115.                     continue;

  116.                 }

  117.                 for (w = 0; w < group_len; w++) {

  118.                     FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(win+w)*16+swb];

  119.                     rd += quantize_band_cost(s, &sce->coeffs[start + w*128],

  120.                                              &s->scoefs[start + w*128], size,

  121.                                              sce->sf_idx[(win+w)*16+swb], aac_cb_out_map[cb],

  122.                                              lambda / band->threshold, INFINITY, NULL, 0);

  123.                 }

  124.                 cost_stay_here = path[swb][cb].cost + rd;

  125.                 cost_get_here  = minrd              + rd + run_bits + 4;

  126.                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]

  127.                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])

  128.                     cost_stay_here += run_bits;

  129.                 if (cost_get_here < cost_stay_here) {

  130.                     path[swb+1][cb].prev_idx = mincb;

  131.                     path[swb+1][cb].cost     = cost_get_here;

  132.                     path[swb+1][cb].run      = 1;

  133.                 } else {

  134.                     path[swb+1][cb].prev_idx = cb;

  135.                     path[swb+1][cb].cost     = cost_stay_here;

  136.                     path[swb+1][cb].run      = path[swb][cb].run + 1;

  137.                 }

  138.                 if (path[swb+1][cb].cost < next_minrd) {

  139.                     next_minrd = path[swb+1][cb].cost;

  140.                     next_mincb = cb;

  141.                 }

  142.             }

  143.         }

  144.         start += sce->ics.swb_sizes[swb];

  145.     }

  146. 

  147.     //convert resulting path from backward-linked list

  148.     stack_len = 0;

  149.     idx       = 0;

  150.     for (cb = 1; cb < CB_TOT_ALL; cb++)

  151.         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)

  152.             idx = cb;

  153.     ppos = max_sfb;

  154.     while (ppos > 0) {

  155.         av_assert1(idx >= 0);

  156.         cb = idx;

  157.         stackrun[stack_len] = path[ppos][cb].run;

  158.         stackcb [stack_len] = cb;

  159.         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;

  160.         ppos -= path[ppos][cb].run;

  161.         stack_len++;

  162.     }

  163.     //perform actual band info encoding

  164.     start = 0;

  165.     for (i = stack_len - 1; i >= 0; i--) {

  166.         cb = aac_cb_out_map[stackcb[i]];

  167.         put_bits(&s->pb, 4, cb);

  168.         count = stackrun[i];

  169.         memset(sce->zeroes + win*16 + start, !cb, count);

  170.         //XXX: memset when band_type is also uint8_t

  171.         for (j = 0; j < count; j++) {

  172.             sce->band_type[win*16 + start] = cb;

  173.             start++;

  174.         }

  175.         while (count >= run_esc) {

  176.             put_bits(&s->pb, run_bits, run_esc);

  177.             count -= run_esc;

  178.         }

  179.         put_bits(&s->pb, run_bits, count);

  180.     }

  181. }

  182. 

  183. static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,

  184.                                   int win, int group_len, const float lambda)

  185. {

  186.     BandCodingPath path[120][CB_TOT_ALL];

  187.     int w, swb, cb, start, size;

  188.     int i, j;

  189.     const int max_sfb  = sce->ics.max_sfb;

  190.     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;

  191.     const int run_esc  = (1 << run_bits) - 1;

  192.     int idx, ppos, count;

  193.     int stackrun[120], stackcb[120], stack_len;

  194.     float next_minbits = INFINITY;

  195.     int next_mincb = 0;

  196. 

  197.     abs_pow34_v(s->scoefs, sce->coeffs, 1024);

  198.     start = win*128;

  199.     for (cb = 0; cb < CB_TOT_ALL; cb++) {

  200.         path[0][cb].cost     = run_bits+4;

  201.         path[0][cb].prev_idx = -1;

  202.         path[0][cb].run      = 0;

  203.     }

  204.     for (swb = 0; swb < max_sfb; swb++) {

  205.         size = sce->ics.swb_sizes[swb];

  206.         if (sce->zeroes[win*16 + swb]) {

  207.             float cost_stay_here = path[swb][0].cost;

  208.             float cost_get_here  = next_minbits + run_bits + 4;

  209.             if (   run_value_bits[sce->ics.num_windows == 8][path[swb][0].run]

  210.                 != run_value_bits[sce->ics.num_windows == 8][path[swb][0].run+1])

  211.                 cost_stay_here += run_bits;

  212.             if (cost_get_here < cost_stay_here) {

  213.                 path[swb+1][0].prev_idx = next_mincb;

  214.                 path[swb+1][0].cost     = cost_get_here;

  215.                 path[swb+1][0].run      = 1;

  216.             } else {

  217.                 path[swb+1][0].prev_idx = 0;

  218.                 path[swb+1][0].cost     = cost_stay_here;

  219.                 path[swb+1][0].run      = path[swb][0].run + 1;

  220.             }

  221.             next_minbits = path[swb+1][0].cost;

  222.             next_mincb = 0;

  223.             for (cb = 1; cb < CB_TOT_ALL; cb++) {

  224.                 path[swb+1][cb].cost = 61450;

  225.                 path[swb+1][cb].prev_idx = -1;

  226.                 path[swb+1][cb].run = 0;

  227.             }

  228.         } else {

  229.             float minbits = next_minbits;

  230.             int mincb = next_mincb;

  231.             int startcb = sce->band_type[win*16+swb];

  232.             startcb = aac_cb_in_map[startcb];

  233.             next_minbits = INFINITY;

  234.             next_mincb = 0;

  235.             for (cb = 0; cb < startcb; cb++) {

  236.                 path[swb+1][cb].cost = 61450;

  237.                 path[swb+1][cb].prev_idx = -1;

  238.                 path[swb+1][cb].run = 0;

  239.             }

  240.             for (cb = startcb; cb < CB_TOT_ALL; cb++) {

  241.                 float cost_stay_here, cost_get_here;

  242.                 float bits = 0.0f;

  243.                 if (cb >= 12 && sce->band_type[win*16+swb] != aac_cb_out_map[cb]) {

  244.                     path[swb+1][cb].cost = 61450;

  245.                     path[swb+1][cb].prev_idx = -1;

  246.                     path[swb+1][cb].run = 0;

  247.                     continue;

  248.                 }

  249.                 for (w = 0; w < group_len; w++) {

  250.                     bits += quantize_band_cost(s, &sce->coeffs[start + w*128],

  251.                                                &s->scoefs[start + w*128], size,

  252.                                                sce->sf_idx[win*16+swb],

  253.                                                aac_cb_out_map[cb],

  254.                                                0, INFINITY, NULL, 0);

  255.                 }

  256.                 cost_stay_here = path[swb][cb].cost + bits;

  257.                 cost_get_here  = minbits            + bits + run_bits + 4;

  258.                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]

  259.                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])

  260.                     cost_stay_here += run_bits;

  261.                 if (cost_get_here < cost_stay_here) {

  262.                     path[swb+1][cb].prev_idx = mincb;

  263.                     path[swb+1][cb].cost     = cost_get_here;

  264.                     path[swb+1][cb].run      = 1;

  265.                 } else {

  266.                     path[swb+1][cb].prev_idx = cb;

  267.                     path[swb+1][cb].cost     = cost_stay_here;

  268.                     path[swb+1][cb].run      = path[swb][cb].run + 1;

  269.                 }

  270.                 if (path[swb+1][cb].cost < next_minbits) {

  271.                     next_minbits = path[swb+1][cb].cost;

  272.                     next_mincb = cb;

  273.                 }

  274.             }

  275.         }

  276.         start += sce->ics.swb_sizes[swb];

  277.     }

  278. 

  279.     //convert resulting path from backward-linked list

  280.     stack_len = 0;

  281.     idx       = 0;

  282.     for (cb = 1; cb < CB_TOT_ALL; cb++)

  283.         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)

  284.             idx = cb;

  285.     ppos = max_sfb;

  286.     while (ppos > 0) {

  287.         av_assert1(idx >= 0);

  288.         cb = idx;

  289.         stackrun[stack_len] = path[ppos][cb].run;

  290.         stackcb [stack_len] = cb;

  291.         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;

  292.         ppos -= path[ppos][cb].run;

  293.         stack_len++;

  294.     }

  295.     //perform actual band info encoding

  296.     start = 0;

  297.     for (i = stack_len - 1; i >= 0; i--) {

  298.         cb = aac_cb_out_map[stackcb[i]];

  299.         put_bits(&s->pb, 4, cb);

  300.         count = stackrun[i];

  301.         memset(sce->zeroes + win*16 + start, !cb, count);

  302.         //XXX: memset when band_type is also uint8_t

  303.         for (j = 0; j < count; j++) {

  304.             sce->band_type[win*16 + start] = cb;

  305.             start++;

  306.         }

  307.         while (count >= run_esc) {

  308.             put_bits(&s->pb, run_bits, run_esc);

  309.             count -= run_esc;

  310.         }

  311.         put_bits(&s->pb, run_bits, count);

  312.     }

  313. }

  314. 

  315. typedef struct TrellisPath {

  316.     float cost;

  317.     int prev;

  318. } TrellisPath;

  319. 

  320. #define TRELLIS_STAGES 121

  321. #define TRELLIS_STATES (SCALE_MAX_DIFF+1)

  322. 

  323. static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement *sce)

  324. {

  325.     int w, g, start = 0;

  326.     int minscaler_n = sce->sf_idx[0], minscaler_i = sce->sf_idx[0];

  327.     int bands = 0;

  328. 

  329.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  330.         start = 0;

  331.         for (g = 0;  g < sce->ics.num_swb; g++) {

  332.             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {

  333.                 sce->sf_idx[w*16+g] = av_clip(ceilf(log2f(sce->is_ener[w*16+g])*2), -155, 100);

  334.                 minscaler_i = FFMIN(minscaler_i, sce->sf_idx[w*16+g]);

  335.                 bands++;

  336.             } else if (sce->band_type[w*16+g] == NOISE_BT) {

  337.                 sce->sf_idx[w*16+g] = av_clip(4+log2f(sce->pns_ener[w*16+g])*2, -100, 155);

  338.                 minscaler_n = FFMIN(minscaler_n, sce->sf_idx[w*16+g]);

  339.                 bands++;

  340.             }

  341.             start += sce->ics.swb_sizes[g];

  342.         }

  343.     }

  344. 

  345.     if (!bands)

  346.         return;

  347. 

  348.     /* Clip the scalefactor indices */

  349.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  350.         for (g = 0;  g < sce->ics.num_swb; g++) {

  351.             if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {

  352.                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_i, minscaler_i + SCALE_MAX_DIFF);

  353.             } else if (sce->band_type[w*16+g] == NOISE_BT) {

  354.                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler_n, minscaler_n + SCALE_MAX_DIFF);

  355.             }

  356.         }

  357.     }

  358. }

  359. 

  360. static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,

  361.                                        SingleChannelElement *sce,

  362.                                        const float lambda)

  363. {

  364.     int q, w, w2, g, start = 0;

  365.     int i, j;

  366.     int idx;

  367.     TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];

  368.     int bandaddr[TRELLIS_STAGES];

  369.     int minq;

  370.     float mincost;

  371.     float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f;

  372.     int q0, q1, qcnt = 0;

  373. 

  374.     for (i = 0; i < 1024; i++) {

  375.         float t = fabsf(sce->coeffs[i]);

  376.         if (t > 0.0f) {

  377.             q0f = FFMIN(q0f, t);

  378.             q1f = FFMAX(q1f, t);

  379.             qnrgf += t*t;

  380.             qcnt++;

  381.         }

  382.     }

  383. 

  384.     if (!qcnt) {

  385.         memset(sce->sf_idx, 0, sizeof(sce->sf_idx));

  386.         memset(sce->zeroes, 1, sizeof(sce->zeroes));

  387.         return;

  388.     }

  389. 

  390.     //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped

  391.     q0 = coef2minsf(q0f);

  392.     //maximum scalefactor index is when maximum coefficient after quantizing is still not zero

  393.     q1 = coef2maxsf(q1f);

  394.     if (q1 - q0 > 60) {

  395.         int q0low  = q0;

  396.         int q1high = q1;

  397.         //minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped

  398.         int qnrg = av_clip_uint8(log2f(sqrtf(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512);

  399.         q1 = qnrg + 30;

  400.         q0 = qnrg - 30;

  401.         if (q0 < q0low) {

  402.             q1 += q0low - q0;

  403.             q0  = q0low;

  404.         } else if (q1 > q1high) {

  405.             q0 -= q1 - q1high;

  406.             q1  = q1high;

  407.         }

  408.     }

  409. 

  410.     for (i = 0; i < TRELLIS_STATES; i++) {

  411.         paths[0][i].cost    = 0.0f;

  412.         paths[0][i].prev    = -1;

  413.     }

  414.     for (j = 1; j < TRELLIS_STAGES; j++) {

  415.         for (i = 0; i < TRELLIS_STATES; i++) {

  416.             paths[j][i].cost    = INFINITY;

  417.             paths[j][i].prev    = -2;

  418.         }

  419.     }

  420.     idx = 1;

  421.     abs_pow34_v(s->scoefs, sce->coeffs, 1024);

  422.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  423.         start = w*128;

  424.         for (g = 0; g < sce->ics.num_swb; g++) {

  425.             const float *coefs = &sce->coeffs[start];

  426.             float qmin, qmax;

  427.             int nz = 0;

  428. 

  429.             bandaddr[idx] = w * 16 + g;

  430.             qmin = INT_MAX;

  431.             qmax = 0.0f;

  432.             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {

  433.                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];

  434.                 if (band->energy <= band->threshold || band->threshold == 0.0f) {

  435.                     sce->zeroes[(w+w2)*16+g] = 1;

  436.                     continue;

  437.                 }

  438.                 sce->zeroes[(w+w2)*16+g] = 0;

  439.                 nz = 1;

  440.                 for (i = 0; i < sce->ics.swb_sizes[g]; i++) {

  441.                     float t = fabsf(coefs[w2*128+i]);

  442.                     if (t > 0.0f)

  443.                         qmin = FFMIN(qmin, t);

  444.                     qmax = FFMAX(qmax, t);

  445.                 }

  446.             }

  447.             if (nz) {

  448.                 int minscale, maxscale;

  449.                 float minrd = INFINITY;

  450.                 float maxval;

  451.                 //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped

  452.                 minscale = coef2minsf(qmin);

  453.                 //maximum scalefactor index is when maximum coefficient after quantizing is still not zero

  454.                 maxscale = coef2maxsf(qmax);

  455.                 minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);

  456.                 maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);

  457.                 maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start);

  458.                 for (q = minscale; q < maxscale; q++) {

  459.                     float dist = 0;

  460.                     int cb = find_min_book(maxval, sce->sf_idx[w*16+g]);

  461.                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {

  462.                         FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];

  463.                         dist += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],

  464.                                                    q + q0, cb, lambda / band->threshold, INFINITY, NULL, 0);

  465.                     }

  466.                     minrd = FFMIN(minrd, dist);

  467. 

  468.                     for (i = 0; i < q1 - q0; i++) {

  469.                         float cost;

  470.                         cost = paths[idx - 1][i].cost + dist

  471.                                + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];

  472.                         if (cost < paths[idx][q].cost) {

  473.                             paths[idx][q].cost    = cost;

  474.                             paths[idx][q].prev    = i;

  475.                         }

  476.                     }

  477.                 }

  478.             } else {

  479.                 for (q = 0; q < q1 - q0; q++) {

  480.                     paths[idx][q].cost = paths[idx - 1][q].cost + 1;

  481.                     paths[idx][q].prev = q;

  482.                 }

  483.             }

  484.             sce->zeroes[w*16+g] = !nz;

  485.             start += sce->ics.swb_sizes[g];

  486.             idx++;

  487.         }

  488.     }

  489.     idx--;

  490.     mincost = paths[idx][0].cost;

  491.     minq    = 0;

  492.     for (i = 1; i < TRELLIS_STATES; i++) {

  493.         if (paths[idx][i].cost < mincost) {

  494.             mincost = paths[idx][i].cost;

  495.             minq = i;

  496.         }

  497.     }

  498.     while (idx) {

  499.         sce->sf_idx[bandaddr[idx]] = minq + q0;

  500.         minq = paths[idx][minq].prev;

  501.         idx--;

  502.     }

  503.     //set the same quantizers inside window groups

  504.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])

  505.         for (g = 0;  g < sce->ics.num_swb; g++)

  506.             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)

  507.                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];

  508. }

  509. 

  510. /**

  511.  * two-loop quantizers search taken from ISO 13818-7 Appendix C

  512.  */

  513. static void search_for_quantizers_twoloop(AVCodecContext *avctx,

  514.                                           AACEncContext *s,

  515.                                           SingleChannelElement *sce,

  516.                                           const float lambda)

  517. {

  518.     int start = 0, i, w, w2, g;

  519.     int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels * (lambda / 120.f);

  520.     float dists[128] = { 0 }, uplims[128] = { 0 };

  521.     float maxvals[128];

  522.     int fflag, minscaler;

  523.     int its  = 0;

  524.     int allz = 0;

  525.     float minthr = INFINITY;

  526. 

  527.     // for values above this the decoder might end up in an endless loop

  528.     // due to always having more bits than what can be encoded.

  529.     destbits = FFMIN(destbits, 5800);

  530.     //XXX: some heuristic to determine initial quantizers will reduce search time

  531.     //determine zero bands and upper limits

  532.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  533.         for (g = 0;  g < sce->ics.num_swb; g++) {

  534.             int nz = 0;

  535.             float uplim = 0.0f, energy = 0.0f;

  536.             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {

  537.                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];

  538.                 uplim  += band->threshold;

  539.                 energy += band->energy;

  540.                 if (band->energy <= band->threshold || band->threshold == 0.0f) {

  541.                     sce->zeroes[(w+w2)*16+g] = 1;

  542.                     continue;

  543.                 }

  544.                 nz = 1;

  545.             }

  546.             uplims[w*16+g] = uplim *512;

  547.             sce->zeroes[w*16+g] = !nz;

  548.             if (nz)

  549.                 minthr = FFMIN(minthr, uplim);

  550.             allz |= nz;

  551.         }

  552.     }

  553.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  554.         for (g = 0;  g < sce->ics.num_swb; g++) {

  555.             if (sce->zeroes[w*16+g]) {

  556.                 sce->sf_idx[w*16+g] = SCALE_ONE_POS;

  557.                 continue;

  558.             }

  559.             sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2f(uplims[w*16+g]/minthr)*4,59);

  560.         }

  561.     }

  562. 

  563.     if (!allz)

  564.         return;

  565.     abs_pow34_v(s->scoefs, sce->coeffs, 1024);

  566. 

  567.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  568.         start = w*128;

  569.         for (g = 0;  g < sce->ics.num_swb; g++) {

  570.             const float *scaled = s->scoefs + start;

  571.             maxvals[w*16+g] = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled);

  572.             start += sce->ics.swb_sizes[g];

  573.         }

  574.     }

  575. 

  576.     //perform two-loop search

  577.     //outer loop - improve quality

  578.     do {

  579.         int tbits, qstep;

  580.         minscaler = sce->sf_idx[0];

  581.         //inner loop - quantize spectrum to fit into given number of bits

  582.         qstep = its ? 1 : 32;

  583.         do {

  584.             int prev = -1;

  585.             tbits = 0;

  586.             for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  587.                 start = w*128;

  588.                 for (g = 0;  g < sce->ics.num_swb; g++) {

  589.                     const float *coefs = &sce->coeffs[start];

  590.                     const float *scaled = &s->scoefs[start];

  591.                     int bits = 0;

  592.                     int cb;

  593.                     float dist = 0.0f;

  594. 

  595.                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {

  596.                         start += sce->ics.swb_sizes[g];

  597.                         continue;

  598.                     }

  599.                     minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);

  600.                     cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);

  601.                     for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {

  602.                         int b;

  603.                         dist += quantize_band_cost(s, coefs + w2*128,

  604.                                                    scaled + w2*128,

  605.                                                    sce->ics.swb_sizes[g],

  606.                                                    sce->sf_idx[w*16+g],

  607.                                                    cb,

  608.                                                    1.0f,

  609.                                                    INFINITY,

  610.                                                    &b,

  611.                                                    0);

  612.                         bits += b;

  613.                     }

  614.                     dists[w*16+g] = dist - bits;

  615.                     if (prev != -1) {

  616.                         bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];

  617.                     }

  618.                     tbits += bits;

  619.                     start += sce->ics.swb_sizes[g];

  620.                     prev = sce->sf_idx[w*16+g];

  621.                 }

  622.             }

  623.             if (tbits > destbits) {

  624.                 for (i = 0; i < 128; i++)

  625.                     if (sce->sf_idx[i] < 218 - qstep)

  626.                         sce->sf_idx[i] += qstep;

  627.             } else {

  628.                 for (i = 0; i < 128; i++)

  629.                     if (sce->sf_idx[i] > 60 - qstep)

  630.                         sce->sf_idx[i] -= qstep;

  631.             }

  632.             qstep >>= 1;

  633.             if (!qstep && tbits > destbits*1.02 && sce->sf_idx[0] < 217)

  634.                 qstep = 1;

  635.         } while (qstep);

  636. 

  637.         fflag = 0;

  638.         minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);

  639. 

  640.         for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  641.             for (g = 0; g < sce->ics.num_swb; g++) {

  642.                 int prevsc = sce->sf_idx[w*16+g];

  643.                 if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60) {

  644.                     if (find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]-1))

  645.                         sce->sf_idx[w*16+g]--;

  646.                     else //Try to make sure there is some energy in every band

  647.                         sce->sf_idx[w*16+g]-=2;

  648.                 }

  649.                 sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);

  650.                 sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);

  651.                 if (sce->sf_idx[w*16+g] != prevsc)

  652.                     fflag = 1;

  653.                 sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);

  654.             }

  655.         }

  656.         its++;

  657.     } while (fflag && its < 10);

  658. }

  659. 

  660. static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,

  661.                                        SingleChannelElement *sce,

  662.                                        const float lambda)

  663. {

  664.     int start = 0, i, w, w2, g;

  665.     float uplim[128], maxq[128];

  666.     int minq, maxsf;

  667.     float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;

  668.     int last = 0, lastband = 0, curband = 0;

  669.     float avg_energy = 0.0;

  670.     if (sce->ics.num_windows == 1) {

  671.         start = 0;

  672.         for (i = 0; i < 1024; i++) {

  673.             if (i - start >= sce->ics.swb_sizes[curband]) {

  674.                 start += sce->ics.swb_sizes[curband];

  675.                 curband++;

  676.             }

  677.             if (sce->coeffs[i]) {

  678.                 avg_energy += sce->coeffs[i] * sce->coeffs[i];

  679.                 last = i;

  680.                 lastband = curband;

  681.             }

  682.         }

  683.     } else {

  684.         for (w = 0; w < 8; w++) {

  685.             const float *coeffs = &sce->coeffs[w*128];

  686.             curband = start = 0;

  687.             for (i = 0; i < 128; i++) {

  688.                 if (i - start >= sce->ics.swb_sizes[curband]) {

  689.                     start += sce->ics.swb_sizes[curband];

  690.                     curband++;

  691.                 }

  692.                 if (coeffs[i]) {

  693.                     avg_energy += coeffs[i] * coeffs[i];

  694.                     last = FFMAX(last, i);

  695.                     lastband = FFMAX(lastband, curband);

  696.                 }

  697.             }

  698.         }

  699.     }

  700.     last++;

  701.     avg_energy /= last;

  702.     if (avg_energy == 0.0f) {

  703.         for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)

  704.             sce->sf_idx[i] = SCALE_ONE_POS;

  705.         return;

  706.     }

  707.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  708.         start = w*128;

  709.         for (g = 0; g < sce->ics.num_swb; g++) {

  710.             float *coefs   = &sce->coeffs[start];

  711.             const int size = sce->ics.swb_sizes[g];

  712.             int start2 = start, end2 = start + size, peakpos = start;

  713.             float maxval = -1, thr = 0.0f, t;

  714.             maxq[w*16+g] = 0.0f;

  715.             if (g > lastband) {

  716.                 maxq[w*16+g] = 0.0f;

  717.                 start += size;

  718.                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)

  719.                     memset(coefs + w2*128, 0, sizeof(coefs[0])*size);

  720.                 continue;

  721.             }

  722.             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {

  723.                 for (i = 0; i < size; i++) {

  724.                     float t = coefs[w2*128+i]*coefs[w2*128+i];

  725.                     maxq[w*16+g] = FFMAX(maxq[w*16+g], fabsf(coefs[w2*128 + i]));

  726.                     thr += t;

  727.                     if (sce->ics.num_windows == 1 && maxval < t) {

  728.                         maxval  = t;

  729.                         peakpos = start+i;

  730.                     }

  731.                 }

  732.             }

  733.             if (sce->ics.num_windows == 1) {

  734.                 start2 = FFMAX(peakpos - 2, start2);

  735.                 end2   = FFMIN(peakpos + 3, end2);

  736.             } else {

  737.                 start2 -= start;

  738.                 end2   -= start;

  739.             }

  740.             start += size;

  741.             thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);

  742.             t   = 1.0 - (1.0 * start2 / last);

  743.             uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);

  744.         }

  745.     }

  746.     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));

  747.     abs_pow34_v(s->scoefs, sce->coeffs, 1024);

  748.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  749.         start = w*128;

  750.         for (g = 0;  g < sce->ics.num_swb; g++) {

  751.             const float *coefs  = &sce->coeffs[start];

  752.             const float *scaled = &s->scoefs[start];

  753.             const int size      = sce->ics.swb_sizes[g];

  754.             int scf, prev_scf, step;

  755.             int min_scf = -1, max_scf = 256;

  756.             float curdiff;

  757.             if (maxq[w*16+g] < 21.544) {

  758.                 sce->zeroes[w*16+g] = 1;

  759.                 start += size;

  760.                 continue;

  761.             }

  762.             sce->zeroes[w*16+g] = 0;

  763.             scf  = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2f(1/maxq[w*16+g])*16/3, 60, 218);

  764.             for (;;) {

  765.                 float dist = 0.0f;

  766.                 int quant_max;

  767. 

  768.                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {

  769.                     int b;

  770.                     dist += quantize_band_cost(s, coefs + w2*128,

  771.                                                scaled + w2*128,

  772.                                                sce->ics.swb_sizes[g],

  773.                                                scf,

  774.                                                ESC_BT,

  775.                                                lambda,

  776.                                                INFINITY,

  777.                                                &b,

  778.                                                0);

  779.                     dist -= b;

  780.                 }

  781.                 dist *= 1.0f / 512.0f / lambda;

  782.                 quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[POW_SF2_ZERO - scf + SCALE_ONE_POS - SCALE_DIV_512], ROUND_STANDARD);

  783.                 if (quant_max >= 8191) { // too much, return to the previous quantizer

  784.                     sce->sf_idx[w*16+g] = prev_scf;

  785.                     break;

  786.                 }

  787.                 prev_scf = scf;

  788.                 curdiff = fabsf(dist - uplim[w*16+g]);

  789.                 if (curdiff <= 1.0f)

  790.                     step = 0;

  791.                 else

  792.                     step = log2f(curdiff);

  793.                 if (dist > uplim[w*16+g])

  794.                     step = -step;

  795.                 scf += step;

  796.                 scf = av_clip_uint8(scf);

  797.                 step = scf - prev_scf;

  798.                 if (FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)) {

  799.                     sce->sf_idx[w*16+g] = av_clip(scf, min_scf, max_scf);

  800.                     break;

  801.                 }

  802.                 if (step > 0)

  803.                     min_scf = prev_scf;

  804.                 else

  805.                     max_scf = prev_scf;

  806.             }

  807.             start += size;

  808.         }

  809.     }

  810.     minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;

  811.     for (i = 1; i < 128; i++) {

  812.         if (!sce->sf_idx[i])

  813.             sce->sf_idx[i] = sce->sf_idx[i-1];

  814.         else

  815.             minq = FFMIN(minq, sce->sf_idx[i]);

  816.     }

  817.     if (minq == INT_MAX)

  818.         minq = 0;

  819.     minq = FFMIN(minq, SCALE_MAX_POS);

  820.     maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);

  821.     for (i = 126; i >= 0; i--) {

  822.         if (!sce->sf_idx[i])

  823.             sce->sf_idx[i] = sce->sf_idx[i+1];

  824.         sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);

  825.     }

  826. }

  827. 

  828. static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,

  829.                                        SingleChannelElement *sce,

  830.                                        const float lambda)

  831. {

  832.     int i, w, w2, g;

  833.     int minq = 255;

  834. 

  835.     memset(sce->sf_idx, 0, sizeof(sce->sf_idx));

  836.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  837.         for (g = 0; g < sce->ics.num_swb; g++) {

  838.             for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {

  839.                 FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];

  840.                 if (band->energy <= band->threshold) {

  841.                     sce->sf_idx[(w+w2)*16+g] = 218;

  842.                     sce->zeroes[(w+w2)*16+g] = 1;

  843.                 } else {

  844.                     sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2f(band->threshold), 80, 218);

  845.                     sce->zeroes[(w+w2)*16+g] = 0;

  846.                 }

  847.                 minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);

  848.             }

  849.         }

  850.     }

  851.     for (i = 0; i < 128; i++) {

  852.         sce->sf_idx[i] = 140;

  853.         //av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);

  854.     }

  855.     //set the same quantizers inside window groups

  856.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])

  857.         for (g = 0;  g < sce->ics.num_swb; g++)

  858.             for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)

  859.                 sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];

  860. }

  861. 

  862. static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)

  863. {

  864.     int start = 0, w, w2, g;

  865.     const float lambda = s->lambda;

  866.     const float freq_mult = avctx->sample_rate/(1024.0f/sce->ics.num_windows)/2.0f;

  867.     const float spread_threshold = NOISE_SPREAD_THRESHOLD*(lambda/120.f);

  868.     const float thr_mult = NOISE_LAMBDA_NUMERATOR/lambda;

  869. 

  870.     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {

  871.         start = 0;

  872.         for (g = 0;  g < sce->ics.num_swb; g++) {

  873.             if (start*freq_mult > NOISE_LOW_LIMIT*(lambda/170.0f)) {

  874.                 float energy = 0.0f, threshold = 0.0f, spread = 0.0f;

  875.                 for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {

  876.                     FFPsyBand *band = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];

  877.                     energy += band->energy;

  878.                     threshold += band->threshold;

  879.                     spread += band->spread;

  880.                 }

  881.                 if (spread > spread_threshold*sce->ics.group_len[w] &&

  882.                     ((sce->zeroes[w*16+g] && energy >= threshold) ||

  883.                     energy < threshold*thr_mult*sce->ics.group_len[w])) {

  884.                     sce->band_type[w*16+g] = NOISE_BT;

  885.                     sce->pns_ener[w*16+g] = energy / sce->ics.group_len[w];

  886.                     sce->zeroes[w*16+g] = 0;

  887.                 }

  888.             }

  889.             start += sce->ics.swb_sizes[g];

  890.         }

  891.     }

  892. }

  893. 

  894. static void search_for_ms(AACEncContext *s, ChannelElement *cpe)

  895. {

  896.     int start = 0, i, w, w2, g;

  897.     float M[128], S[128];

  898.     float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;

  899.     const float lambda = s->lambda;

  900.     SingleChannelElement *sce0 = &cpe->ch[0];

  901.     SingleChannelElement *sce1 = &cpe->ch[1];

  902.     if (!cpe->common_window)

  903.         return;

  904.     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {

  905.         start = 0;

  906.         for (g = 0;  g < sce0->ics.num_swb; g++) {

  907.             if (!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]) {

  908.                 float dist1 = 0.0f, dist2 = 0.0f;

  909.                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {

  910.                     FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];

  911.                     FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];

  912.                     float minthr = FFMIN(band0->threshold, band1->threshold);

  913.                     float maxthr = FFMAX(band0->threshold, band1->threshold);

  914.                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {

  915.                         M[i] = (sce0->coeffs[start+(w+w2)*128+i]

  916.                               + sce1->coeffs[start+(w+w2)*128+i]) * 0.5;

  917.                         S[i] =  M[i]

  918.                               - sce1->coeffs[start+(w+w2)*128+i];

  919.                     }

  920.                     abs_pow34_v(L34, sce0->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);

  921.                     abs_pow34_v(R34, sce1->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);

  922.                     abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);

  923.                     abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);

  924.                     dist1 += quantize_band_cost(s, &sce0->coeffs[start + (w+w2)*128],

  925.                                                 L34,

  926.                                                 sce0->ics.swb_sizes[g],

  927.                                                 sce0->sf_idx[(w+w2)*16+g],

  928.                                                 sce0->band_type[(w+w2)*16+g],

  929.                                                 lambda / band0->threshold, INFINITY, NULL, 0);

  930.                     dist1 += quantize_band_cost(s, &sce1->coeffs[start + (w+w2)*128],

  931.                                                 R34,

  932.                                                 sce1->ics.swb_sizes[g],

  933.                                                 sce1->sf_idx[(w+w2)*16+g],

  934.                                                 sce1->band_type[(w+w2)*16+g],

  935.                                                 lambda / band1->threshold, INFINITY, NULL, 0);

  936.                     dist2 += quantize_band_cost(s, M,

  937.                                                 M34,

  938.                                                 sce0->ics.swb_sizes[g],

  939.                                                 sce0->sf_idx[(w+w2)*16+g],

  940.                                                 sce0->band_type[(w+w2)*16+g],

  941.                                                 lambda / maxthr, INFINITY, NULL, 0);

  942.                     dist2 += quantize_band_cost(s, S,

  943.                                                 S34,

  944.                                                 sce1->ics.swb_sizes[g],

  945.                                                 sce1->sf_idx[(w+w2)*16+g],

  946.                                                 sce1->band_type[(w+w2)*16+g],

  947.                                                 lambda / minthr, INFINITY, NULL, 0);

  948.                 }

  949.                 cpe->ms_mask[w*16+g] = dist2 < dist1;

  950.             }

  951.             start += sce0->ics.swb_sizes[g];

  952.         }

  953.     }

  954. }

  955. 

  956. AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = {

  957.     [AAC_CODER_FAAC] = {

  958.         search_for_quantizers_faac,

  959.         encode_window_bands_info,

  960.         quantize_and_encode_band,

  961.         set_special_band_scalefactors,

  962.         search_for_pns,

  963.         search_for_ms,

  964.         search_for_is,

  965.     },

  966.     [AAC_CODER_ANMR] = {

  967.         search_for_quantizers_anmr,

  968.         encode_window_bands_info,

  969.         quantize_and_encode_band,

  970.         set_special_band_scalefactors,

  971.         search_for_pns,

  972.         search_for_ms,

  973.         search_for_is,

  974.     },

  975.     [AAC_CODER_TWOLOOP] = {

  976.         search_for_quantizers_twoloop,

  977.         codebook_trellis_rate,

  978.         quantize_and_encode_band,

  979.         set_special_band_scalefactors,

  980.         search_for_pns,

  981.         search_for_ms,

  982.         search_for_is,

  983.     },

  984.     [AAC_CODER_FAST] = {

  985.         search_for_quantizers_fast,

  986.         encode_window_bands_info,

  987.         quantize_and_encode_band,

  988.         set_special_band_scalefactors,

  989.         search_for_pns,

  990.         search_for_ms,

  991.         search_for_is,

  992.     },

  993. };