LCOV - code coverage report
Current view: top level - src/libavcodec - aacpsy.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 367 445 82.5 %
Date: 2017-01-28 02:43:52 Functions: 16 18 88.9 %

          Line data    Source code
       1             : /*
       2             :  * AAC encoder psychoacoustic model
       3             :  * Copyright (C) 2008 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 encoder psychoacoustic model
      25             :  */
      26             : 
      27             : #include "libavutil/attributes.h"
      28             : #include "libavutil/ffmath.h"
      29             : 
      30             : #include "avcodec.h"
      31             : #include "aactab.h"
      32             : #include "psymodel.h"
      33             : 
      34             : /***********************************
      35             :  *              TODOs:
      36             :  * try other bitrate controlling mechanism (maybe use ratecontrol.c?)
      37             :  * control quality for quality-based output
      38             :  **********************************/
      39             : 
      40             : /**
      41             :  * constants for 3GPP AAC psychoacoustic model
      42             :  * @{
      43             :  */
      44             : #define PSY_3GPP_THR_SPREAD_HI   1.5f // spreading factor for low-to-hi threshold spreading  (15 dB/Bark)
      45             : #define PSY_3GPP_THR_SPREAD_LOW  3.0f // spreading factor for hi-to-low threshold spreading  (30 dB/Bark)
      46             : /* spreading factor for low-to-hi energy spreading, long block, > 22kbps/channel (20dB/Bark) */
      47             : #define PSY_3GPP_EN_SPREAD_HI_L1 2.0f
      48             : /* spreading factor for low-to-hi energy spreading, long block, <= 22kbps/channel (15dB/Bark) */
      49             : #define PSY_3GPP_EN_SPREAD_HI_L2 1.5f
      50             : /* spreading factor for low-to-hi energy spreading, short block (15 dB/Bark) */
      51             : #define PSY_3GPP_EN_SPREAD_HI_S  1.5f
      52             : /* spreading factor for hi-to-low energy spreading, long block (30dB/Bark) */
      53             : #define PSY_3GPP_EN_SPREAD_LOW_L 3.0f
      54             : /* spreading factor for hi-to-low energy spreading, short block (20dB/Bark) */
      55             : #define PSY_3GPP_EN_SPREAD_LOW_S 2.0f
      56             : 
      57             : #define PSY_3GPP_RPEMIN      0.01f
      58             : #define PSY_3GPP_RPELEV      2.0f
      59             : 
      60             : #define PSY_3GPP_C1          3.0f           /* log2(8) */
      61             : #define PSY_3GPP_C2          1.3219281f     /* log2(2.5) */
      62             : #define PSY_3GPP_C3          0.55935729f    /* 1 - C2 / C1 */
      63             : 
      64             : #define PSY_SNR_1DB          7.9432821e-1f  /* -1dB */
      65             : #define PSY_SNR_25DB         3.1622776e-3f  /* -25dB */
      66             : 
      67             : #define PSY_3GPP_SAVE_SLOPE_L  -0.46666667f
      68             : #define PSY_3GPP_SAVE_SLOPE_S  -0.36363637f
      69             : #define PSY_3GPP_SAVE_ADD_L    -0.84285712f
      70             : #define PSY_3GPP_SAVE_ADD_S    -0.75f
      71             : #define PSY_3GPP_SPEND_SLOPE_L  0.66666669f
      72             : #define PSY_3GPP_SPEND_SLOPE_S  0.81818181f
      73             : #define PSY_3GPP_SPEND_ADD_L   -0.35f
      74             : #define PSY_3GPP_SPEND_ADD_S   -0.26111111f
      75             : #define PSY_3GPP_CLIP_LO_L      0.2f
      76             : #define PSY_3GPP_CLIP_LO_S      0.2f
      77             : #define PSY_3GPP_CLIP_HI_L      0.95f
      78             : #define PSY_3GPP_CLIP_HI_S      0.75f
      79             : 
      80             : #define PSY_3GPP_AH_THR_LONG    0.5f
      81             : #define PSY_3GPP_AH_THR_SHORT   0.63f
      82             : 
      83             : #define PSY_PE_FORGET_SLOPE  511
      84             : 
      85             : enum {
      86             :     PSY_3GPP_AH_NONE,
      87             :     PSY_3GPP_AH_INACTIVE,
      88             :     PSY_3GPP_AH_ACTIVE
      89             : };
      90             : 
      91             : #define PSY_3GPP_BITS_TO_PE(bits) ((bits) * 1.18f)
      92             : #define PSY_3GPP_PE_TO_BITS(bits) ((bits) / 1.18f)
      93             : 
      94             : /* LAME psy model constants */
      95             : #define PSY_LAME_FIR_LEN 21         ///< LAME psy model FIR order
      96             : #define AAC_BLOCK_SIZE_LONG 1024    ///< long block size
      97             : #define AAC_BLOCK_SIZE_SHORT 128    ///< short block size
      98             : #define AAC_NUM_BLOCKS_SHORT 8      ///< number of blocks in a short sequence
      99             : #define PSY_LAME_NUM_SUBBLOCKS 3    ///< Number of sub-blocks in each short block
     100             : 
     101             : /**
     102             :  * @}
     103             :  */
     104             : 
     105             : /**
     106             :  * information for single band used by 3GPP TS26.403-inspired psychoacoustic model
     107             :  */
     108             : typedef struct AacPsyBand{
     109             :     float energy;       ///< band energy
     110             :     float thr;          ///< energy threshold
     111             :     float thr_quiet;    ///< threshold in quiet
     112             :     float nz_lines;     ///< number of non-zero spectral lines
     113             :     float active_lines; ///< number of active spectral lines
     114             :     float pe;           ///< perceptual entropy
     115             :     float pe_const;     ///< constant part of the PE calculation
     116             :     float norm_fac;     ///< normalization factor for linearization
     117             :     int   avoid_holes;  ///< hole avoidance flag
     118             : }AacPsyBand;
     119             : 
     120             : /**
     121             :  * single/pair channel context for psychoacoustic model
     122             :  */
     123             : typedef struct AacPsyChannel{
     124             :     AacPsyBand band[128];               ///< bands information
     125             :     AacPsyBand prev_band[128];          ///< bands information from the previous frame
     126             : 
     127             :     float       win_energy;              ///< sliding average of channel energy
     128             :     float       iir_state[2];            ///< hi-pass IIR filter state
     129             :     uint8_t     next_grouping;           ///< stored grouping scheme for the next frame (in case of 8 short window sequence)
     130             :     enum WindowSequence next_window_seq; ///< window sequence to be used in the next frame
     131             :     /* LAME psy model specific members */
     132             :     float attack_threshold;              ///< attack threshold for this channel
     133             :     float prev_energy_subshort[AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS];
     134             :     int   prev_attack;                   ///< attack value for the last short block in the previous sequence
     135             : }AacPsyChannel;
     136             : 
     137             : /**
     138             :  * psychoacoustic model frame type-dependent coefficients
     139             :  */
     140             : typedef struct AacPsyCoeffs{
     141             :     float ath;           ///< absolute threshold of hearing per bands
     142             :     float barks;         ///< Bark value for each spectral band in long frame
     143             :     float spread_low[2]; ///< spreading factor for low-to-high threshold spreading in long frame
     144             :     float spread_hi [2]; ///< spreading factor for high-to-low threshold spreading in long frame
     145             :     float min_snr;       ///< minimal SNR
     146             : }AacPsyCoeffs;
     147             : 
     148             : /**
     149             :  * 3GPP TS26.403-inspired psychoacoustic model specific data
     150             :  */
     151             : typedef struct AacPsyContext{
     152             :     int chan_bitrate;     ///< bitrate per channel
     153             :     int frame_bits;       ///< average bits per frame
     154             :     int fill_level;       ///< bit reservoir fill level
     155             :     struct {
     156             :         float min;        ///< minimum allowed PE for bit factor calculation
     157             :         float max;        ///< maximum allowed PE for bit factor calculation
     158             :         float previous;   ///< allowed PE of the previous frame
     159             :         float correction; ///< PE correction factor
     160             :     } pe;
     161             :     AacPsyCoeffs psy_coef[2][64];
     162             :     AacPsyChannel *ch;
     163             :     float global_quality; ///< normalized global quality taken from avctx
     164             : }AacPsyContext;
     165             : 
     166             : /**
     167             :  * LAME psy model preset struct
     168             :  */
     169             : typedef struct PsyLamePreset {
     170             :     int   quality;  ///< Quality to map the rest of the vaules to.
     171             :      /* This is overloaded to be both kbps per channel in ABR mode, and
     172             :       * requested quality in constant quality mode.
     173             :       */
     174             :     float st_lrm;   ///< short threshold for L, R, and M channels
     175             : } PsyLamePreset;
     176             : 
     177             : /**
     178             :  * LAME psy model preset table for ABR
     179             :  */
     180             : static const PsyLamePreset psy_abr_map[] = {
     181             : /* TODO: Tuning. These were taken from LAME. */
     182             : /* kbps/ch st_lrm   */
     183             :     {  8,  6.60},
     184             :     { 16,  6.60},
     185             :     { 24,  6.60},
     186             :     { 32,  6.60},
     187             :     { 40,  6.60},
     188             :     { 48,  6.60},
     189             :     { 56,  6.60},
     190             :     { 64,  6.40},
     191             :     { 80,  6.00},
     192             :     { 96,  5.60},
     193             :     {112,  5.20},
     194             :     {128,  5.20},
     195             :     {160,  5.20}
     196             : };
     197             : 
     198             : /**
     199             : * LAME psy model preset table for constant quality
     200             : */
     201             : static const PsyLamePreset psy_vbr_map[] = {
     202             : /* vbr_q  st_lrm    */
     203             :     { 0,  4.20},
     204             :     { 1,  4.20},
     205             :     { 2,  4.20},
     206             :     { 3,  4.20},
     207             :     { 4,  4.20},
     208             :     { 5,  4.20},
     209             :     { 6,  4.20},
     210             :     { 7,  4.20},
     211             :     { 8,  4.20},
     212             :     { 9,  4.20},
     213             :     {10,  4.20}
     214             : };
     215             : 
     216             : /**
     217             :  * LAME psy model FIR coefficient table
     218             :  */
     219             : static const float psy_fir_coeffs[] = {
     220             :     -8.65163e-18 * 2, -0.00851586 * 2, -6.74764e-18 * 2, 0.0209036 * 2,
     221             :     -3.36639e-17 * 2, -0.0438162 * 2,  -1.54175e-17 * 2, 0.0931738 * 2,
     222             :     -5.52212e-17 * 2, -0.313819 * 2
     223             : };
     224             : 
     225             : #if ARCH_MIPS
     226             : #   include "mips/aacpsy_mips.h"
     227             : #endif /* ARCH_MIPS */
     228             : 
     229             : /**
     230             :  * Calculate the ABR attack threshold from the above LAME psymodel table.
     231             :  */
     232          27 : static float lame_calc_attack_threshold(int bitrate)
     233             : {
     234             :     /* Assume max bitrate to start with */
     235          27 :     int lower_range = 12, upper_range = 12;
     236          27 :     int lower_range_kbps = psy_abr_map[12].quality;
     237          27 :     int upper_range_kbps = psy_abr_map[12].quality;
     238             :     int i;
     239             : 
     240             :     /* Determine which bitrates the value specified falls between.
     241             :      * If the loop ends without breaking our above assumption of 320kbps was correct.
     242             :      */
     243         218 :     for (i = 1; i < 13; i++) {
     244         214 :         if (FFMAX(bitrate, psy_abr_map[i].quality) != bitrate) {
     245          23 :             upper_range = i;
     246          23 :             upper_range_kbps = psy_abr_map[i    ].quality;
     247          23 :             lower_range = i - 1;
     248          23 :             lower_range_kbps = psy_abr_map[i - 1].quality;
     249          23 :             break; /* Upper range found */
     250             :         }
     251             :     }
     252             : 
     253             :     /* Determine which range the value specified is closer to */
     254          27 :     if ((upper_range_kbps - bitrate) > (bitrate - lower_range_kbps))
     255          23 :         return psy_abr_map[lower_range].st_lrm;
     256           4 :     return psy_abr_map[upper_range].st_lrm;
     257             : }
     258             : 
     259             : /**
     260             :  * LAME psy model specific initialization
     261             :  */
     262          12 : static av_cold void lame_window_init(AacPsyContext *ctx, AVCodecContext *avctx)
     263             : {
     264             :     int i, j;
     265             : 
     266          39 :     for (i = 0; i < avctx->channels; i++) {
     267          27 :         AacPsyChannel *pch = &ctx->ch[i];
     268             : 
     269          27 :         if (avctx->flags & AV_CODEC_FLAG_QSCALE)
     270           0 :             pch->attack_threshold = psy_vbr_map[avctx->global_quality / FF_QP2LAMBDA].st_lrm;
     271             :         else
     272          27 :             pch->attack_threshold = lame_calc_attack_threshold(avctx->bit_rate / avctx->channels / 1000);
     273             : 
     274         675 :         for (j = 0; j < AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS; j++)
     275         648 :             pch->prev_energy_subshort[j] = 10.0f;
     276             :     }
     277          12 : }
     278             : 
     279             : /**
     280             :  * Calculate Bark value for given line.
     281             :  */
     282         768 : static av_cold float calc_bark(float f)
     283             : {
     284         768 :     return 13.3f * atanf(0.00076f * f) + 3.5f * atanf((f / 7500.0f) * (f / 7500.0f));
     285             : }
     286             : 
     287             : #define ATH_ADD 4
     288             : /**
     289             :  * Calculate ATH value for given frequency.
     290             :  * Borrowed from Lame.
     291             :  */
     292       15646 : static av_cold float ath(float f, float add)
     293             : {
     294       15646 :     f /= 1000.0f;
     295       15646 :     return    3.64 * pow(f, -0.8)
     296       15646 :             - 6.8  * exp(-0.6  * (f - 3.4) * (f - 3.4))
     297       15646 :             + 6.0  * exp(-0.15 * (f - 8.7) * (f - 8.7))
     298       15646 :             + (0.6 + 0.04 * add) * 0.001 * f * f * f * f;
     299             : }
     300             : 
     301          12 : static av_cold int psy_3gpp_init(FFPsyContext *ctx) {
     302             :     AacPsyContext *pctx;
     303             :     float bark;
     304             :     int i, j, g, start;
     305             :     float prev, minscale, minath, minsnr, pe_min;
     306          12 :     int chan_bitrate = ctx->avctx->bit_rate / ((ctx->avctx->flags & CODEC_FLAG_QSCALE) ? 2.0f : ctx->avctx->channels);
     307             : 
     308          12 :     const int bandwidth    = ctx->cutoff ? ctx->cutoff : AAC_CUTOFF(ctx->avctx);
     309          12 :     const float num_bark   = calc_bark((float)bandwidth);
     310             : 
     311          12 :     ctx->model_priv_data = av_mallocz(sizeof(AacPsyContext));
     312          12 :     if (!ctx->model_priv_data)
     313           0 :         return AVERROR(ENOMEM);
     314          12 :     pctx = (AacPsyContext*) ctx->model_priv_data;
     315          12 :     pctx->global_quality = (ctx->avctx->global_quality ? ctx->avctx->global_quality : 120) * 0.01f;
     316             : 
     317          12 :     if (ctx->avctx->flags & CODEC_FLAG_QSCALE) {
     318             :         /* Use the target average bitrate to compute spread parameters */
     319           0 :         chan_bitrate = (int)(chan_bitrate / 120.0 * (ctx->avctx->global_quality ? ctx->avctx->global_quality : 120));
     320             :     }
     321             : 
     322          12 :     pctx->chan_bitrate = chan_bitrate;
     323          12 :     pctx->frame_bits   = FFMIN(2560, chan_bitrate * AAC_BLOCK_SIZE_LONG / ctx->avctx->sample_rate);
     324          12 :     pctx->pe.min       =  8.0f * AAC_BLOCK_SIZE_LONG * bandwidth / (ctx->avctx->sample_rate * 2.0f);
     325          12 :     pctx->pe.max       = 12.0f * AAC_BLOCK_SIZE_LONG * bandwidth / (ctx->avctx->sample_rate * 2.0f);
     326          12 :     ctx->bitres.size   = 6144 - pctx->frame_bits;
     327          12 :     ctx->bitres.size  -= ctx->bitres.size % 8;
     328          12 :     pctx->fill_level   = ctx->bitres.size;
     329          12 :     minath = ath(3410 - 0.733 * ATH_ADD, ATH_ADD);
     330          36 :     for (j = 0; j < 2; j++) {
     331          24 :         AacPsyCoeffs *coeffs = pctx->psy_coef[j];
     332          24 :         const uint8_t *band_sizes = ctx->bands[j];
     333          24 :         float line_to_frequency = ctx->avctx->sample_rate / (j ? 256.f : 2048.0f);
     334          24 :         float avg_chan_bits = chan_bitrate * (j ? 128.0f : 1024.0f) / ctx->avctx->sample_rate;
     335             :         /* reference encoder uses 2.4% here instead of 60% like the spec says */
     336          24 :         float bark_pe = 0.024f * PSY_3GPP_BITS_TO_PE(avg_chan_bits) / num_bark;
     337          24 :         float en_spread_low = j ? PSY_3GPP_EN_SPREAD_LOW_S : PSY_3GPP_EN_SPREAD_LOW_L;
     338             :         /* High energy spreading for long blocks <= 22kbps/channel and short blocks are the same. */
     339          24 :         float en_spread_hi  = (j || (chan_bitrate <= 22.0f)) ? PSY_3GPP_EN_SPREAD_HI_S : PSY_3GPP_EN_SPREAD_HI_L1;
     340             : 
     341          24 :         i = 0;
     342          24 :         prev = 0.0;
     343         780 :         for (g = 0; g < ctx->num_bands[j]; g++) {
     344         756 :             i += band_sizes[g];
     345         756 :             bark = calc_bark((i-1) * line_to_frequency);
     346         756 :             coeffs[g].barks = (bark + prev) / 2.0;
     347         756 :             prev = bark;
     348             :         }
     349         756 :         for (g = 0; g < ctx->num_bands[j] - 1; g++) {
     350         732 :             AacPsyCoeffs *coeff = &coeffs[g];
     351         732 :             float bark_width = coeffs[g+1].barks - coeffs->barks;
     352         732 :             coeff->spread_low[0] = ff_exp10(-bark_width * PSY_3GPP_THR_SPREAD_LOW);
     353         732 :             coeff->spread_hi [0] = ff_exp10(-bark_width * PSY_3GPP_THR_SPREAD_HI);
     354         732 :             coeff->spread_low[1] = ff_exp10(-bark_width * en_spread_low);
     355         732 :             coeff->spread_hi [1] = ff_exp10(-bark_width * en_spread_hi);
     356         732 :             pe_min = bark_pe * bark_width;
     357         732 :             minsnr = exp2(pe_min / band_sizes[g]) - 1.5f;
     358         732 :             coeff->min_snr = av_clipf(1.0f / minsnr, PSY_SNR_25DB, PSY_SNR_1DB);
     359             :         }
     360          24 :         start = 0;
     361         780 :         for (g = 0; g < ctx->num_bands[j]; g++) {
     362         756 :             minscale = ath(start * line_to_frequency, ATH_ADD);
     363       13824 :             for (i = 1; i < band_sizes[g]; i++)
     364       13068 :                 minscale = FFMIN(minscale, ath((start + i) * line_to_frequency, ATH_ADD));
     365         756 :             coeffs[g].ath = minscale - minath;
     366         756 :             start += band_sizes[g];
     367             :         }
     368             :     }
     369             : 
     370          12 :     pctx->ch = av_mallocz_array(ctx->avctx->channels, sizeof(AacPsyChannel));
     371          12 :     if (!pctx->ch) {
     372           0 :         av_freep(&ctx->model_priv_data);
     373           0 :         return AVERROR(ENOMEM);
     374             :     }
     375             : 
     376          12 :     lame_window_init(pctx, ctx->avctx);
     377             : 
     378          12 :     return 0;
     379             : }
     380             : 
     381             : /**
     382             :  * IIR filter used in block switching decision
     383             :  */
     384           0 : static float iir_filter(int in, float state[2])
     385             : {
     386             :     float ret;
     387             : 
     388           0 :     ret = 0.7548f * (in - state[0]) + 0.5095f * state[1];
     389           0 :     state[0] = in;
     390           0 :     state[1] = ret;
     391           0 :     return ret;
     392             : }
     393             : 
     394             : /**
     395             :  * window grouping information stored as bits (0 - new group, 1 - group continues)
     396             :  */
     397             : static const uint8_t window_grouping[9] = {
     398             :     0xB6, 0x6C, 0xD8, 0xB2, 0x66, 0xC6, 0x96, 0x36, 0x36
     399             : };
     400             : 
     401             : /**
     402             :  * Tell encoder which window types to use.
     403             :  * @see 3GPP TS26.403 5.4.1 "Blockswitching"
     404             :  */
     405           0 : static av_unused FFPsyWindowInfo psy_3gpp_window(FFPsyContext *ctx,
     406             :                                                  const int16_t *audio,
     407             :                                                  const int16_t *la,
     408             :                                                  int channel, int prev_type)
     409             : {
     410             :     int i, j;
     411           0 :     int br               = ((AacPsyContext*)ctx->model_priv_data)->chan_bitrate;
     412           0 :     int attack_ratio     = br <= 16000 ? 18 : 10;
     413           0 :     AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data;
     414           0 :     AacPsyChannel *pch  = &pctx->ch[channel];
     415           0 :     uint8_t grouping     = 0;
     416           0 :     int next_type        = pch->next_window_seq;
     417           0 :     FFPsyWindowInfo wi  = { { 0 } };
     418             : 
     419           0 :     if (la) {
     420             :         float s[8], v;
     421           0 :         int switch_to_eight = 0;
     422           0 :         float sum = 0.0, sum2 = 0.0;
     423           0 :         int attack_n = 0;
     424           0 :         int stay_short = 0;
     425           0 :         for (i = 0; i < 8; i++) {
     426           0 :             for (j = 0; j < 128; j++) {
     427           0 :                 v = iir_filter(la[i*128+j], pch->iir_state);
     428           0 :                 sum += v*v;
     429             :             }
     430           0 :             s[i]  = sum;
     431           0 :             sum2 += sum;
     432             :         }
     433           0 :         for (i = 0; i < 8; i++) {
     434           0 :             if (s[i] > pch->win_energy * attack_ratio) {
     435           0 :                 attack_n        = i + 1;
     436           0 :                 switch_to_eight = 1;
     437           0 :                 break;
     438             :             }
     439             :         }
     440           0 :         pch->win_energy = pch->win_energy*7/8 + sum2/64;
     441             : 
     442           0 :         wi.window_type[1] = prev_type;
     443           0 :         switch (prev_type) {
     444             :         case ONLY_LONG_SEQUENCE:
     445           0 :             wi.window_type[0] = switch_to_eight ? LONG_START_SEQUENCE : ONLY_LONG_SEQUENCE;
     446           0 :             next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : ONLY_LONG_SEQUENCE;
     447           0 :             break;
     448             :         case LONG_START_SEQUENCE:
     449           0 :             wi.window_type[0] = EIGHT_SHORT_SEQUENCE;
     450           0 :             grouping = pch->next_grouping;
     451           0 :             next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE;
     452           0 :             break;
     453             :         case LONG_STOP_SEQUENCE:
     454           0 :             wi.window_type[0] = switch_to_eight ? LONG_START_SEQUENCE : ONLY_LONG_SEQUENCE;
     455           0 :             next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : ONLY_LONG_SEQUENCE;
     456           0 :             break;
     457             :         case EIGHT_SHORT_SEQUENCE:
     458           0 :             stay_short = next_type == EIGHT_SHORT_SEQUENCE || switch_to_eight;
     459           0 :             wi.window_type[0] = stay_short ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE;
     460           0 :             grouping = next_type == EIGHT_SHORT_SEQUENCE ? pch->next_grouping : 0;
     461           0 :             next_type = switch_to_eight ? EIGHT_SHORT_SEQUENCE : LONG_STOP_SEQUENCE;
     462           0 :             break;
     463             :         }
     464             : 
     465           0 :         pch->next_grouping = window_grouping[attack_n];
     466           0 :         pch->next_window_seq = next_type;
     467             :     } else {
     468           0 :         for (i = 0; i < 3; i++)
     469           0 :             wi.window_type[i] = prev_type;
     470           0 :         grouping = (prev_type == EIGHT_SHORT_SEQUENCE) ? window_grouping[0] : 0;
     471             :     }
     472             : 
     473           0 :     wi.window_shape   = 1;
     474           0 :     if (wi.window_type[0] != EIGHT_SHORT_SEQUENCE) {
     475           0 :         wi.num_windows = 1;
     476           0 :         wi.grouping[0] = 1;
     477             :     } else {
     478           0 :         int lastgrp = 0;
     479           0 :         wi.num_windows = 8;
     480           0 :         for (i = 0; i < 8; i++) {
     481           0 :             if (!((grouping >> i) & 1))
     482           0 :                 lastgrp = i;
     483           0 :             wi.grouping[lastgrp]++;
     484             :         }
     485             :     }
     486             : 
     487           0 :     return wi;
     488             : }
     489             : 
     490             : /* 5.6.1.2 "Calculation of Bit Demand" */
     491       12123 : static int calc_bit_demand(AacPsyContext *ctx, float pe, int bits, int size,
     492             :                            int short_window)
     493             : {
     494       12123 :     const float bitsave_slope  = short_window ? PSY_3GPP_SAVE_SLOPE_S  : PSY_3GPP_SAVE_SLOPE_L;
     495       12123 :     const float bitsave_add    = short_window ? PSY_3GPP_SAVE_ADD_S    : PSY_3GPP_SAVE_ADD_L;
     496       12123 :     const float bitspend_slope = short_window ? PSY_3GPP_SPEND_SLOPE_S : PSY_3GPP_SPEND_SLOPE_L;
     497       12123 :     const float bitspend_add   = short_window ? PSY_3GPP_SPEND_ADD_S   : PSY_3GPP_SPEND_ADD_L;
     498       12123 :     const float clip_low       = short_window ? PSY_3GPP_CLIP_LO_S     : PSY_3GPP_CLIP_LO_L;
     499       12123 :     const float clip_high      = short_window ? PSY_3GPP_CLIP_HI_S     : PSY_3GPP_CLIP_HI_L;
     500             :     float clipped_pe, bit_save, bit_spend, bit_factor, fill_level, forgetful_min_pe;
     501             : 
     502       12123 :     ctx->fill_level += ctx->frame_bits - bits;
     503       12123 :     ctx->fill_level  = av_clip(ctx->fill_level, 0, size);
     504       12123 :     fill_level = av_clipf((float)ctx->fill_level / size, clip_low, clip_high);
     505       12123 :     clipped_pe = av_clipf(pe, ctx->pe.min, ctx->pe.max);
     506       12123 :     bit_save   = (fill_level + bitsave_add) * bitsave_slope;
     507             :     assert(bit_save <= 0.3f && bit_save >= -0.05000001f);
     508       12123 :     bit_spend  = (fill_level + bitspend_add) * bitspend_slope;
     509             :     assert(bit_spend <= 0.5f && bit_spend >= -0.1f);
     510             :     /* The bit factor graph in the spec is obviously incorrect.
     511             :      *      bit_spend + ((bit_spend - bit_spend))...
     512             :      * The reference encoder subtracts everything from 1, but also seems incorrect.
     513             :      *      1 - bit_save + ((bit_spend + bit_save))...
     514             :      * Hopefully below is correct.
     515             :      */
     516       12123 :     bit_factor = 1.0f - bit_save + ((bit_spend - bit_save) / (ctx->pe.max - ctx->pe.min)) * (clipped_pe - ctx->pe.min);
     517             :     /* NOTE: The reference encoder attempts to center pe max/min around the current pe.
     518             :      * Here we do that by slowly forgetting pe.min when pe stays in a range that makes
     519             :      * it unlikely (ie: above the mean)
     520             :      */
     521       12123 :     ctx->pe.max = FFMAX(pe, ctx->pe.max);
     522       24246 :     forgetful_min_pe = ((ctx->pe.min * PSY_PE_FORGET_SLOPE)
     523       12123 :         + FFMAX(ctx->pe.min, pe * (pe / ctx->pe.max))) / (PSY_PE_FORGET_SLOPE + 1);
     524       12123 :     ctx->pe.min = FFMIN(pe, forgetful_min_pe);
     525             : 
     526             :     /* NOTE: allocate a minimum of 1/8th average frame bits, to avoid
     527             :      *   reservoir starvation from producing zero-bit frames
     528             :      */
     529       12123 :     return FFMIN(
     530             :         ctx->frame_bits * bit_factor,
     531             :         FFMAX(ctx->frame_bits + size - bits, ctx->frame_bits / 8));
     532             : }
     533             : 
     534     2114840 : static float calc_pe_3gpp(AacPsyBand *band)
     535             : {
     536             :     float pe, a;
     537             : 
     538     2114840 :     band->pe           = 0.0f;
     539     2114840 :     band->pe_const     = 0.0f;
     540     2114840 :     band->active_lines = 0.0f;
     541     2114840 :     if (band->energy > band->thr) {
     542     1983000 :         a  = log2f(band->energy);
     543     1983000 :         pe = a - log2f(band->thr);
     544     1983000 :         band->active_lines = band->nz_lines;
     545     1983000 :         if (pe < PSY_3GPP_C1) {
     546      867753 :             pe = pe * PSY_3GPP_C3 + PSY_3GPP_C2;
     547      867753 :             a  = a  * PSY_3GPP_C3 + PSY_3GPP_C2;
     548      867753 :             band->active_lines *= PSY_3GPP_C3;
     549             :         }
     550     1983000 :         band->pe       = pe * band->nz_lines;
     551     1983000 :         band->pe_const = a  * band->nz_lines;
     552             :     }
     553             : 
     554     2114840 :     return band->pe;
     555             : }
     556             : 
     557       31525 : static float calc_reduction_3gpp(float a, float desired_pe, float pe,
     558             :                                  float active_lines)
     559             : {
     560             :     float thr_avg, reduction;
     561             : 
     562       31525 :     if(active_lines == 0.0)
     563          24 :         return 0;
     564             : 
     565       31501 :     thr_avg   = exp2f((a - pe) / (4.0f * active_lines));
     566       31501 :     reduction = exp2f((a - desired_pe) / (4.0f * active_lines)) - thr_avg;
     567             : 
     568       31501 :     return FFMAX(reduction, 0.0f);
     569             : }
     570             : 
     571     1501976 : static float calc_reduced_thr_3gpp(AacPsyBand *band, float min_snr,
     572             :                                    float reduction)
     573             : {
     574     1501976 :     float thr = band->thr;
     575             : 
     576     1501976 :     if (band->energy > thr) {
     577     1412898 :         thr = sqrtf(thr);
     578     1412898 :         thr = sqrtf(thr) + reduction;
     579     1412898 :         thr *= thr;
     580     1412898 :         thr *= thr;
     581             : 
     582             :         /* This deviates from the 3GPP spec to match the reference encoder.
     583             :          * It performs min(thr_reduced, max(thr, energy/min_snr)) only for bands
     584             :          * that have hole avoidance on (active or inactive). It always reduces the
     585             :          * threshold of bands with hole avoidance off.
     586             :          */
     587     1412898 :         if (thr > band->energy * min_snr && band->avoid_holes != PSY_3GPP_AH_NONE) {
     588      385130 :             thr = FFMAX(band->thr, band->energy * min_snr);
     589      385130 :             band->avoid_holes = PSY_3GPP_AH_ACTIVE;
     590             :         }
     591             :     }
     592             : 
     593     1501976 :     return thr;
     594             : }
     595             : 
     596             : #ifndef calc_thr_3gpp
     597       12123 : static void calc_thr_3gpp(const FFPsyWindowInfo *wi, const int num_bands, AacPsyChannel *pch,
     598             :                           const uint8_t *band_sizes, const float *coefs, const int cutoff)
     599             : {
     600             :     int i, w, g;
     601       12123 :     int start = 0, wstart = 0;
     602       26339 :     for (w = 0; w < wi->num_windows*16; w += 16) {
     603       14216 :         wstart = 0;
     604      627080 :         for (g = 0; g < num_bands; g++) {
     605      612864 :             AacPsyBand *band = &pch->band[w+g];
     606             : 
     607      612864 :             float form_factor = 0.0f;
     608             :             float Temp;
     609      612864 :             band->energy = 0.0f;
     610      612864 :             if (wstart < cutoff) {
     611    12030293 :                 for (i = 0; i < band_sizes[g]; i++) {
     612    11446592 :                     band->energy += coefs[start+i] * coefs[start+i];
     613    11446592 :                     form_factor  += sqrtf(fabs(coefs[start+i]));
     614             :                 }
     615             :             }
     616      612864 :             Temp = band->energy > 0 ? sqrtf((float)band_sizes[g] / band->energy) : 0;
     617      612864 :             band->thr      = band->energy * 0.001258925f;
     618      612864 :             band->nz_lines = form_factor * sqrtf(Temp);
     619             : 
     620      612864 :             start += band_sizes[g];
     621      612864 :             wstart += band_sizes[g];
     622             :         }
     623             :     }
     624       12123 : }
     625             : #endif /* calc_thr_3gpp */
     626             : 
     627             : #ifndef psy_hp_filter
     628        8006 : static void psy_hp_filter(const float *firbuf, float *hpfsmpl, const float *psy_fir_coeffs)
     629             : {
     630             :     int i, j;
     631     8206150 :     for (i = 0; i < AAC_BLOCK_SIZE_LONG; i++) {
     632             :         float sum1, sum2;
     633     8198144 :         sum1 = firbuf[i + (PSY_LAME_FIR_LEN - 1) / 2];
     634     8198144 :         sum2 = 0.0;
     635    49188864 :         for (j = 0; j < ((PSY_LAME_FIR_LEN - 1) / 2) - 1; j += 2) {
     636    40990720 :             sum1 += psy_fir_coeffs[j] * (firbuf[i + j] + firbuf[i + PSY_LAME_FIR_LEN - j]);
     637    40990720 :             sum2 += psy_fir_coeffs[j + 1] * (firbuf[i + j + 1] + firbuf[i + PSY_LAME_FIR_LEN - j - 1]);
     638             :         }
     639             :         /* NOTE: The LAME psymodel expects it's input in the range -32768 to 32768.
     640             :          *       Tuning this for normalized floats would be difficult. */
     641     8198144 :         hpfsmpl[i] = (sum1 + sum2) * 32768.0f;
     642             :     }
     643        8006 : }
     644             : #endif /* psy_hp_filter */
     645             : 
     646             : /**
     647             :  * Calculate band thresholds as suggested in 3GPP TS26.403
     648             :  */
     649       12123 : static void psy_3gpp_analyze_channel(FFPsyContext *ctx, int channel,
     650             :                                      const float *coefs, const FFPsyWindowInfo *wi)
     651             : {
     652       12123 :     AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data;
     653       12123 :     AacPsyChannel *pch  = &pctx->ch[channel];
     654             :     int i, w, g;
     655       12123 :     float desired_bits, desired_pe, delta_pe, reduction= NAN, spread_en[128] = {0};
     656       12123 :     float a = 0.0f, active_lines = 0.0f, norm_fac = 0.0f;
     657       12123 :     float pe = pctx->chan_bitrate > 32000 ? 0.0f : FFMAX(50.0f, 100.0f - pctx->chan_bitrate * 100.0f / 32000.0f);
     658       12123 :     const int      num_bands   = ctx->num_bands[wi->num_windows == 8];
     659       12123 :     const uint8_t *band_sizes  = ctx->bands[wi->num_windows == 8];
     660       12123 :     AacPsyCoeffs  *coeffs      = pctx->psy_coef[wi->num_windows == 8];
     661       12123 :     const float avoid_hole_thr = wi->num_windows == 8 ? PSY_3GPP_AH_THR_SHORT : PSY_3GPP_AH_THR_LONG;
     662       12123 :     const int bandwidth        = ctx->cutoff ? ctx->cutoff : AAC_CUTOFF(ctx->avctx);
     663       12123 :     const int cutoff           = bandwidth * 2048 / wi->num_windows / ctx->avctx->sample_rate;
     664             : 
     665             :     //calculate energies, initial thresholds and related values - 5.4.2 "Threshold Calculation"
     666       12123 :     calc_thr_3gpp(wi, num_bands, pch, band_sizes, coefs, cutoff);
     667             : 
     668             :     //modify thresholds and energies - spread, threshold in quiet, pre-echo control
     669       26339 :     for (w = 0; w < wi->num_windows*16; w += 16) {
     670       14216 :         AacPsyBand *bands = &pch->band[w];
     671             : 
     672             :         /* 5.4.2.3 "Spreading" & 5.4.3 "Spread Energy Calculation" */
     673       14216 :         spread_en[0] = bands[0].energy;
     674      612864 :         for (g = 1; g < num_bands; g++) {
     675      598648 :             bands[g].thr   = FFMAX(bands[g].thr,    bands[g-1].thr * coeffs[g].spread_hi[0]);
     676      598648 :             spread_en[w+g] = FFMAX(bands[g].energy, spread_en[w+g-1] * coeffs[g].spread_hi[1]);
     677             :         }
     678      612864 :         for (g = num_bands - 2; g >= 0; g--) {
     679      598648 :             bands[g].thr   = FFMAX(bands[g].thr,   bands[g+1].thr * coeffs[g].spread_low[0]);
     680      598648 :             spread_en[w+g] = FFMAX(spread_en[w+g], spread_en[w+g+1] * coeffs[g].spread_low[1]);
     681             :         }
     682             :         //5.4.2.4 "Threshold in quiet"
     683      627080 :         for (g = 0; g < num_bands; g++) {
     684      612864 :             AacPsyBand *band = &bands[g];
     685             : 
     686      612864 :             band->thr_quiet = band->thr = FFMAX(band->thr, coeffs[g].ath);
     687             :             //5.4.2.5 "Pre-echo control"
     688      612864 :             if (!(wi->window_type[0] == LONG_STOP_SEQUENCE || (!w && wi->window_type[1] == LONG_START_SEQUENCE)))
     689      602763 :                 band->thr = FFMAX(PSY_3GPP_RPEMIN*band->thr, FFMIN(band->thr,
     690             :                                   PSY_3GPP_RPELEV*pch->prev_band[w+g].thr_quiet));
     691             : 
     692             :             /* 5.6.1.3.1 "Preparatory steps of the perceptual entropy calculation" */
     693      612864 :             pe += calc_pe_3gpp(band);
     694      612864 :             a  += band->pe_const;
     695      612864 :             active_lines += band->active_lines;
     696             : 
     697             :             /* 5.6.1.3.3 "Selection of the bands for avoidance of holes" */
     698      612864 :             if (spread_en[w+g] * avoid_hole_thr > band->energy || coeffs[g].min_snr > 1.0f)
     699        1200 :                 band->avoid_holes = PSY_3GPP_AH_NONE;
     700             :             else
     701      611664 :                 band->avoid_holes = PSY_3GPP_AH_INACTIVE;
     702             :         }
     703             :     }
     704             : 
     705             :     /* 5.6.1.3.2 "Calculation of the desired perceptual entropy" */
     706       12123 :     ctx->ch[channel].entropy = pe;
     707       12123 :     if (ctx->avctx->flags & CODEC_FLAG_QSCALE) {
     708             :         /* (2.5 * 120) achieves almost transparent rate, and we want to give
     709             :          * ample room downwards, so we make that equivalent to QSCALE=2.4
     710             :          */
     711           0 :         desired_pe = pe * (ctx->avctx->global_quality ? ctx->avctx->global_quality : 120) / (2 * 2.5f * 120.0f);
     712           0 :         desired_bits = FFMIN(2560, PSY_3GPP_PE_TO_BITS(desired_pe));
     713           0 :         desired_pe = PSY_3GPP_BITS_TO_PE(desired_bits); // reflect clipping
     714             : 
     715             :         /* PE slope smoothing */
     716           0 :         if (ctx->bitres.bits > 0) {
     717           0 :             desired_bits = FFMIN(2560, PSY_3GPP_PE_TO_BITS(desired_pe));
     718           0 :             desired_pe = PSY_3GPP_BITS_TO_PE(desired_bits); // reflect clipping
     719             :         }
     720             : 
     721           0 :         pctx->pe.max = FFMAX(pe, pctx->pe.max);
     722           0 :         pctx->pe.min = FFMIN(pe, pctx->pe.min);
     723             :     } else {
     724       12123 :         desired_bits = calc_bit_demand(pctx, pe, ctx->bitres.bits, ctx->bitres.size, wi->num_windows == 8);
     725       12123 :         desired_pe = PSY_3GPP_BITS_TO_PE(desired_bits);
     726             : 
     727             :         /* NOTE: PE correction is kept simple. During initial testing it had very
     728             :          *       little effect on the final bitrate. Probably a good idea to come
     729             :          *       back and do more testing later.
     730             :          */
     731       12123 :         if (ctx->bitres.bits > 0)
     732       12078 :             desired_pe *= av_clipf(pctx->pe.previous / PSY_3GPP_BITS_TO_PE(ctx->bitres.bits),
     733             :                                    0.85f, 1.15f);
     734             :     }
     735       12123 :     pctx->pe.previous = PSY_3GPP_BITS_TO_PE(desired_bits);
     736       12123 :     ctx->bitres.alloc = desired_bits;
     737             : 
     738       12123 :     if (desired_pe < pe) {
     739             :         /* 5.6.1.3.4 "First Estimation of the reduction value" */
     740       25417 :         for (w = 0; w < wi->num_windows*16; w += 16) {
     741       13398 :             reduction = calc_reduction_3gpp(a, desired_pe, pe, active_lines);
     742       13398 :             pe = 0.0f;
     743       13398 :             a  = 0.0f;
     744       13398 :             active_lines = 0.0f;
     745      614740 :             for (g = 0; g < num_bands; g++) {
     746      601342 :                 AacPsyBand *band = &pch->band[w+g];
     747             : 
     748      601342 :                 band->thr = calc_reduced_thr_3gpp(band, coeffs[g].min_snr, reduction);
     749             :                 /* recalculate PE */
     750      601342 :                 pe += calc_pe_3gpp(band);
     751      601342 :                 a  += band->pe_const;
     752      601342 :                 active_lines += band->active_lines;
     753             :             }
     754             :         }
     755             : 
     756             :         /* 5.6.1.3.5 "Second Estimation of the reduction value" */
     757       24235 :         for (i = 0; i < 2; i++) {
     758       18127 :             float pe_no_ah = 0.0f, desired_pe_no_ah;
     759       18127 :             active_lines = a = 0.0f;
     760       37633 :             for (w = 0; w < wi->num_windows*16; w += 16) {
     761      920140 :                 for (g = 0; g < num_bands; g++) {
     762      900634 :                     AacPsyBand *band = &pch->band[w+g];
     763             : 
     764      900634 :                     if (band->avoid_holes != PSY_3GPP_AH_ACTIVE) {
     765      725053 :                         pe_no_ah += band->pe;
     766      725053 :                         a        += band->pe_const;
     767      725053 :                         active_lines += band->active_lines;
     768             :                     }
     769             :                 }
     770             :             }
     771       18127 :             desired_pe_no_ah = FFMAX(desired_pe - (pe - pe_no_ah), 0.0f);
     772       18127 :             if (active_lines > 0.0f)
     773       18127 :                 reduction = calc_reduction_3gpp(a, desired_pe_no_ah, pe_no_ah, active_lines);
     774             : 
     775       18127 :             pe = 0.0f;
     776       37633 :             for (w = 0; w < wi->num_windows*16; w += 16) {
     777      920140 :                 for (g = 0; g < num_bands; g++) {
     778      900634 :                     AacPsyBand *band = &pch->band[w+g];
     779             : 
     780      900634 :                     if (active_lines > 0.0f)
     781      900634 :                         band->thr = calc_reduced_thr_3gpp(band, coeffs[g].min_snr, reduction);
     782      900634 :                     pe += calc_pe_3gpp(band);
     783      900634 :                     if (band->thr > 0.0f)
     784      900634 :                         band->norm_fac = band->active_lines / band->thr;
     785             :                     else
     786           0 :                         band->norm_fac = 0.0f;
     787      900634 :                     norm_fac += band->norm_fac;
     788             :                 }
     789             :             }
     790       18127 :             delta_pe = desired_pe - pe;
     791       18127 :             if (fabs(delta_pe) > 0.05f * desired_pe)
     792        5911 :                 break;
     793             :         }
     794             : 
     795       12019 :         if (pe < 1.15f * desired_pe) {
     796             :             /* 6.6.1.3.6 "Final threshold modification by linearization" */
     797        9819 :             norm_fac = 1.0f / norm_fac;
     798       19638 :             for (w = 0; w < wi->num_windows*16; w += 16) {
     799      490950 :                 for (g = 0; g < num_bands; g++) {
     800      481131 :                     AacPsyBand *band = &pch->band[w+g];
     801             : 
     802      481131 :                     if (band->active_lines > 0.5f) {
     803      451830 :                         float delta_sfb_pe = band->norm_fac * norm_fac * delta_pe;
     804      451830 :                         float thr = band->thr;
     805             : 
     806      451830 :                         thr *= exp2f(delta_sfb_pe / band->active_lines);
     807      451830 :                         if (thr > coeffs[g].min_snr * band->energy && band->avoid_holes == PSY_3GPP_AH_INACTIVE)
     808          77 :                             thr = FFMAX(band->thr, coeffs[g].min_snr * band->energy);
     809      451830 :                         band->thr = thr;
     810             :                     }
     811             :                 }
     812             :             }
     813             :         } else {
     814             :             /* 5.6.1.3.7 "Further perceptual entropy reduction" */
     815        2200 :             g = num_bands;
     816      104800 :             while (pe > desired_pe && g--) {
     817      220106 :                 for (w = 0; w < wi->num_windows*16; w+= 16) {
     818      119706 :                     AacPsyBand *band = &pch->band[w+g];
     819      119706 :                     if (band->avoid_holes != PSY_3GPP_AH_NONE && coeffs[g].min_snr < PSY_SNR_1DB) {
     820         339 :                         coeffs[g].min_snr = PSY_SNR_1DB;
     821         339 :                         band->thr = band->energy * PSY_SNR_1DB;
     822         339 :                         pe += band->active_lines * 1.5f - band->pe;
     823             :                     }
     824             :                 }
     825             :             }
     826             :             /* TODO: allow more holes (unused without mid/side) */
     827             :         }
     828             :     }
     829             : 
     830       26339 :     for (w = 0; w < wi->num_windows*16; w += 16) {
     831      627080 :         for (g = 0; g < num_bands; g++) {
     832      612864 :             AacPsyBand *band     = &pch->band[w+g];
     833      612864 :             FFPsyBand  *psy_band = &ctx->ch[channel].psy_bands[w+g];
     834             : 
     835      612864 :             psy_band->threshold = band->thr;
     836      612864 :             psy_band->energy    = band->energy;
     837      612864 :             psy_band->spread    = band->active_lines * 2.0f / band_sizes[g];
     838      612864 :             psy_band->bits      = PSY_3GPP_PE_TO_BITS(band->pe);
     839             :         }
     840             :     }
     841             : 
     842       12123 :     memcpy(pch->prev_band, pch->band, sizeof(pch->band));
     843       12123 : }
     844             : 
     845        6371 : static void psy_3gpp_analyze(FFPsyContext *ctx, int channel,
     846             :                                    const float **coeffs, const FFPsyWindowInfo *wi)
     847             : {
     848             :     int ch;
     849        6371 :     FFPsyChannelGroup *group = ff_psy_find_group(ctx, channel);
     850             : 
     851       18494 :     for (ch = 0; ch < group->num_ch; ch++)
     852       12123 :         psy_3gpp_analyze_channel(ctx, channel + ch, coeffs[ch], &wi[ch]);
     853        6371 : }
     854             : 
     855          12 : static av_cold void psy_3gpp_end(FFPsyContext *apc)
     856             : {
     857          12 :     AacPsyContext *pctx = (AacPsyContext*) apc->model_priv_data;
     858          12 :     av_freep(&pctx->ch);
     859          12 :     av_freep(&apc->model_priv_data);
     860          12 : }
     861             : 
     862        8058 : static void lame_apply_block_type(AacPsyChannel *ctx, FFPsyWindowInfo *wi, int uselongblock)
     863             : {
     864        8058 :     int blocktype = ONLY_LONG_SEQUENCE;
     865        8058 :     if (uselongblock) {
     866        7879 :         if (ctx->next_window_seq == EIGHT_SHORT_SEQUENCE)
     867         132 :             blocktype = LONG_STOP_SEQUENCE;
     868             :     } else {
     869         179 :         blocktype = EIGHT_SHORT_SEQUENCE;
     870         179 :         if (ctx->next_window_seq == ONLY_LONG_SEQUENCE)
     871         131 :             ctx->next_window_seq = LONG_START_SEQUENCE;
     872         179 :         if (ctx->next_window_seq == LONG_STOP_SEQUENCE)
     873          20 :             ctx->next_window_seq = EIGHT_SHORT_SEQUENCE;
     874             :     }
     875             : 
     876        8058 :     wi->window_type[0] = ctx->next_window_seq;
     877        8058 :     ctx->next_window_seq = blocktype;
     878        8058 : }
     879             : 
     880        8058 : static FFPsyWindowInfo psy_lame_window(FFPsyContext *ctx, const float *audio,
     881             :                                        const float *la, int channel, int prev_type)
     882             : {
     883        8058 :     AacPsyContext *pctx = (AacPsyContext*) ctx->model_priv_data;
     884        8058 :     AacPsyChannel *pch  = &pctx->ch[channel];
     885        8058 :     int grouping     = 0;
     886        8058 :     int uselongblock = 1;
     887        8058 :     int attacks[AAC_NUM_BLOCKS_SHORT + 1] = { 0 };
     888             :     int i;
     889        8058 :     FFPsyWindowInfo wi = { { 0 } };
     890             : 
     891        8058 :     if (la) {
     892             :         float hpfsmpl[AAC_BLOCK_SIZE_LONG];
     893        8006 :         const float *pf = hpfsmpl;
     894             :         float attack_intensity[(AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS];
     895             :         float energy_subshort[(AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS];
     896        8006 :         float energy_short[AAC_NUM_BLOCKS_SHORT + 1] = { 0 };
     897        8006 :         const float *firbuf = la + (AAC_BLOCK_SIZE_SHORT/4 - PSY_LAME_FIR_LEN);
     898        8006 :         int att_sum = 0;
     899             : 
     900             :         /* LAME comment: apply high pass filter of fs/4 */
     901        8006 :         psy_hp_filter(firbuf, hpfsmpl, psy_fir_coeffs);
     902             : 
     903             :         /* Calculate the energies of each sub-shortblock */
     904       32024 :         for (i = 0; i < PSY_LAME_NUM_SUBBLOCKS; i++) {
     905       24018 :             energy_subshort[i] = pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 1) * PSY_LAME_NUM_SUBBLOCKS)];
     906             :             assert(pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 2) * PSY_LAME_NUM_SUBBLOCKS + 1)] > 0);
     907       24018 :             attack_intensity[i] = energy_subshort[i] / pch->prev_energy_subshort[i + ((AAC_NUM_BLOCKS_SHORT - 2) * PSY_LAME_NUM_SUBBLOCKS + 1)];
     908       24018 :             energy_short[0] += energy_subshort[i];
     909             :         }
     910             : 
     911      200150 :         for (i = 0; i < AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS; i++) {
     912      192144 :             const float *const pfe = pf + AAC_BLOCK_SIZE_LONG / (AAC_NUM_BLOCKS_SHORT * PSY_LAME_NUM_SUBBLOCKS);
     913      192144 :             float p = 1.0f;
     914     8262192 :             for (; pf < pfe; pf++)
     915     8070048 :                 p = FFMAX(p, fabsf(*pf));
     916      192144 :             pch->prev_energy_subshort[i] = energy_subshort[i + PSY_LAME_NUM_SUBBLOCKS] = p;
     917      192144 :             energy_short[1 + i / PSY_LAME_NUM_SUBBLOCKS] += p;
     918             :             /* NOTE: The indexes below are [i + 3 - 2] in the LAME source.
     919             :              *       Obviously the 3 and 2 have some significance, or this would be just [i + 1]
     920             :              *       (which is what we use here). What the 3 stands for is ambiguous, as it is both
     921             :              *       number of short blocks, and the number of sub-short blocks.
     922             :              *       It seems that LAME is comparing each sub-block to sub-block + 1 in the
     923             :              *       previous block.
     924             :              */
     925      192144 :             if (p > energy_subshort[i + 1])
     926       94929 :                 p = p / energy_subshort[i + 1];
     927       97215 :             else if (energy_subshort[i + 1] > p * 10.0f)
     928          57 :                 p = energy_subshort[i + 1] / (p * 10.0f);
     929             :             else
     930       97158 :                 p = 0.0;
     931      192144 :             attack_intensity[i + PSY_LAME_NUM_SUBBLOCKS] = p;
     932             :         }
     933             : 
     934             :         /* compare energy between sub-short blocks */
     935      224168 :         for (i = 0; i < (AAC_NUM_BLOCKS_SHORT + 1) * PSY_LAME_NUM_SUBBLOCKS; i++)
     936      216162 :             if (!attacks[i / PSY_LAME_NUM_SUBBLOCKS])
     937      215963 :                 if (attack_intensity[i] > pch->attack_threshold)
     938         208 :                     attacks[i / PSY_LAME_NUM_SUBBLOCKS] = (i % PSY_LAME_NUM_SUBBLOCKS) + 1;
     939             : 
     940             :         /* should have energy change between short blocks, in order to avoid periodic signals */
     941             :         /* Good samples to show the effect are Trumpet test songs */
     942             :         /* GB: tuned (1) to avoid too many short blocks for test sample TRUMPET */
     943             :         /* RH: tuned (2) to let enough short blocks through for test sample FSOL and SNAPS */
     944       72054 :         for (i = 1; i < AAC_NUM_BLOCKS_SHORT + 1; i++) {
     945       64048 :             const float u = energy_short[i - 1];
     946       64048 :             const float v = energy_short[i];
     947       64048 :             const float m = FFMAX(u, v);
     948       64048 :             if (m < 40000) {                          /* (2) */
     949       61052 :                 if (u < 1.7f * v && v < 1.7f * u) {   /* (1) */
     950       57371 :                     if (i == 1 && attacks[0] < attacks[i])
     951          10 :                         attacks[0] = 0;
     952       57371 :                     attacks[i] = 0;
     953             :                 }
     954             :             }
     955       64048 :             att_sum += attacks[i];
     956             :         }
     957             : 
     958        8006 :         if (attacks[0] <= pch->prev_attack)
     959        8006 :             attacks[0] = 0;
     960             : 
     961        8006 :         att_sum += attacks[0];
     962             :         /* 3 below indicates the previous attack happened in the last sub-block of the previous sequence */
     963        8006 :         if (pch->prev_attack == 3 || att_sum) {
     964         160 :             uselongblock = 0;
     965             : 
     966        1440 :             for (i = 1; i < AAC_NUM_BLOCKS_SHORT + 1; i++)
     967        1280 :                 if (attacks[i] && attacks[i-1])
     968           0 :                     attacks[i] = 0;
     969             :         }
     970             :     } else {
     971             :         /* We have no lookahead info, so just use same type as the previous sequence. */
     972          52 :         uselongblock = !(prev_type == EIGHT_SHORT_SEQUENCE);
     973             :     }
     974             : 
     975        8058 :     lame_apply_block_type(pch, &wi, uselongblock);
     976             : 
     977        8058 :     wi.window_type[1] = prev_type;
     978        8058 :     if (wi.window_type[0] != EIGHT_SHORT_SEQUENCE) {
     979             : 
     980        7878 :         wi.num_windows  = 1;
     981        7878 :         wi.grouping[0]  = 1;
     982        7878 :         if (wi.window_type[0] == LONG_START_SEQUENCE)
     983         131 :             wi.window_shape = 0;
     984             :         else
     985        7747 :             wi.window_shape = 1;
     986             : 
     987             :     } else {
     988         180 :         int lastgrp = 0;
     989             : 
     990         180 :         wi.num_windows = 8;
     991         180 :         wi.window_shape = 0;
     992        1620 :         for (i = 0; i < 8; i++) {
     993        1440 :             if (!((pch->next_grouping >> i) & 1))
     994         684 :                 lastgrp = i;
     995        1440 :             wi.grouping[lastgrp]++;
     996             :         }
     997             :     }
     998             : 
     999             :     /* Determine grouping, based on the location of the first attack, and save for
    1000             :      * the next frame.
    1001             :      * FIXME: Move this to analysis.
    1002             :      * TODO: Tune groupings depending on attack location
    1003             :      * TODO: Handle more than one attack in a group
    1004             :      */
    1005       79997 :     for (i = 0; i < 9; i++) {
    1006       72083 :         if (attacks[i]) {
    1007         144 :             grouping = i;
    1008         144 :             break;
    1009             :         }
    1010             :     }
    1011        8058 :     pch->next_grouping = window_grouping[grouping];
    1012             : 
    1013        8058 :     pch->prev_attack = attacks[8];
    1014             : 
    1015        8058 :     return wi;
    1016             : }
    1017             : 
    1018             : const FFPsyModel ff_aac_psy_model =
    1019             : {
    1020             :     .name    = "3GPP TS 26.403-inspired model",
    1021             :     .init    = psy_3gpp_init,
    1022             :     .window  = psy_lame_window,
    1023             :     .analyze = psy_3gpp_analyze,
    1024             :     .end     = psy_3gpp_end,
    1025             : };

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