/* * AAC coefficients encoder * Copyright (C) 2008-2009 Konstantin Shishkov * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * AAC coefficients encoder */ /*********************************** *              TODOs: * speedup quantizer selection * add sane pulse detection ***********************************/ #include "libavutil/libm.h" // brought forward to work around cygwin header breakage #include <float.h> #include "libavutil/mathematics.h"#include "mathops.h"#include "avcodec.h"#include "put_bits.h"#include "aac.h"#include "aacenc.h"#include "aactab.h"#include "aacenctab.h"#include "aacenc_utils.h"#include "aacenc_quantization.h" #include "aacenc_is.h"#include "aacenc_tns.h"#include "aacenc_ltp.h"#include "aacenc_pred.h" #include "libavcodec/aaccoder_twoloop.h" /* Parameter of f(x) = a*(lambda/100), defines the maximum fourier spread * beyond which no PNS is used (since the SFBs contain tone rather than noise) */#define NOISE_SPREAD_THRESHOLD 0.9f /* Parameter of f(x) = a*(100/lambda), defines how much PNS is allowed to * replace low energy non zero bands */#define NOISE_LAMBDA_REPLACE 1.948f #include "libavcodec/aaccoder_trellis.h" /** * structure used in optimal codebook search */typedef struct BandCodingPath {    int prev_idx; ///< pointer to the previous path point    float cost;   ///< path cost    int run;} BandCodingPath; /** * Encode band info for single window group bands. */static void encode_window_bands_info(AACEncContext *s, SingleChannelElement *sce,                                     int win, int group_len, const float lambda){    BandCodingPath path[120][CB_TOT_ALL];    int w, swb, cb, start, size;    int i, j;    const int max_sfb  = sce->ics.max_sfb;    const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;    const int run_esc  = (1 << run_bits) - 1;    int idx, ppos, count;    int stackrun[120], stackcb[120], stack_len;    float next_minrd = INFINITY;    int next_mincb = 0;     abs_pow34_v(s->scoefs, sce->coeffs, 1024);    start = win*128;    for (cb = 0; cb < CB_TOT_ALL; cb++) {        path[0][cb].cost     = 0.0f;        path[0][cb].prev_idx = -1;        path[0][cb].run      = 0;    }    for (swb = 0; swb < max_sfb; swb++) {        size = sce->ics.swb_sizes[swb];        if (sce->zeroes[win*16 + swb]) {            for (cb = 0; cb < CB_TOT_ALL; cb++) {                path[swb+1][cb].prev_idx = cb;                path[swb+1][cb].cost     = path[swb][cb].cost;                path[swb+1][cb].run      = path[swb][cb].run + 1;            }        } else {            float minrd = next_minrd;            int mincb = next_mincb;            next_minrd = INFINITY;            next_mincb = 0;            for (cb = 0; cb < CB_TOT_ALL; cb++) {                float cost_stay_here, cost_get_here;                float rd = 0.0f;                if (cb >= 12 && sce->band_type[win*16+swb] < aac_cb_out_map[cb] ||                    cb  < aac_cb_in_map[sce->band_type[win*16+swb]] && sce->band_type[win*16+swb] > aac_cb_out_map[cb]) {                    path[swb+1][cb].prev_idx = -1;                    path[swb+1][cb].cost     = INFINITY;                    path[swb+1][cb].run      = path[swb][cb].run + 1;                    continue;                }                for (w = 0; w < group_len; w++) {                    FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(win+w)*16+swb];                    rd += quantize_band_cost(s, &sce->coeffs[start + w*128],                                             &s->scoefs[start + w*128], size,                                             sce->sf_idx[(win+w)*16+swb], aac_cb_out_map[cb],                                             lambda / band->threshold, INFINITY, NULL, NULL, 0);                }                cost_stay_here = path[swb][cb].cost + rd;                cost_get_here  = minrd              + rd + run_bits + 4;                if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]                    != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])                    cost_stay_here += run_bits;                if (cost_get_here < cost_stay_here) {                    path[swb+1][cb].prev_idx = mincb;                    path[swb+1][cb].cost     = cost_get_here;                    path[swb+1][cb].run      = 1;                } else {                    path[swb+1][cb].prev_idx = cb;                    path[swb+1][cb].cost     = cost_stay_here;                    path[swb+1][cb].run      = path[swb][cb].run + 1;                }                if (path[swb+1][cb].cost < next_minrd) {                    next_minrd = path[swb+1][cb].cost;                    next_mincb = cb;                }            }        }        start += sce->ics.swb_sizes[swb];    }     //convert resulting path from backward-linked list    stack_len = 0;    idx       = 0;    for (cb = 1; cb < CB_TOT_ALL; cb++)        if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)            idx = cb;    ppos = max_sfb;    while (ppos > 0) {        av_assert1(idx >= 0);        cb = idx;        stackrun[stack_len] = path[ppos][cb].run;        stackcb [stack_len] = cb;        idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;        ppos -= path[ppos][cb].run;        stack_len++;    }    //perform actual band info encoding    start = 0;    for (i = stack_len - 1; i >= 0; i--) {        cb = aac_cb_out_map[stackcb[i]];        put_bits(&s->pb, 4, cb);        count = stackrun[i];        memset(sce->zeroes + win*16 + start, !cb, count);        //XXX: memset when band_type is also uint8_t        for (j = 0; j < count; j++) {            sce->band_type[win*16 + start] = cb;            start++;        }        while (count >= run_esc) {            put_bits(&s->pb, run_bits, run_esc);            count -= run_esc;        }        put_bits(&s->pb, run_bits, count);    }}  typedef struct TrellisPath {    float cost;    int prev;} TrellisPath; #define TRELLIS_STAGES 121#define TRELLIS_STATES (SCALE_MAX_DIFF+1) static void set_special_band_scalefactors(AACEncContext *s, SingleChannelElement *sce){    int w, g;    int prevscaler_n = -255, prevscaler_i = 0;    int bands = 0;     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {        for (g = 0; g < sce->ics.num_swb; g++) {            if (sce->zeroes[w*16+g])                continue;            if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {                sce->sf_idx[w*16+g] = av_clip(roundf(log2f(sce->is_ener[w*16+g])*2), -155, 100);                bands++;            } else if (sce->band_type[w*16+g] == NOISE_BT) {                sce->sf_idx[w*16+g] = av_clip(3+ceilf(log2f(sce->pns_ener[w*16+g])*2), -100, 155);                if (prevscaler_n == -255)                    prevscaler_n = sce->sf_idx[w*16+g];                bands++;            }        }    }     if (!bands)        return;     /* Clip the scalefactor indices */    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {        for (g = 0; g < sce->ics.num_swb; g++) {            if (sce->zeroes[w*16+g])                continue;            if (sce->band_type[w*16+g] == INTENSITY_BT || sce->band_type[w*16+g] == INTENSITY_BT2) {                sce->sf_idx[w*16+g] = prevscaler_i = av_clip(sce->sf_idx[w*16+g], prevscaler_i - SCALE_MAX_DIFF, prevscaler_i + SCALE_MAX_DIFF);            } else if (sce->band_type[w*16+g] == NOISE_BT) {                sce->sf_idx[w*16+g] = prevscaler_n = av_clip(sce->sf_idx[w*16+g], prevscaler_n - SCALE_MAX_DIFF, prevscaler_n + SCALE_MAX_DIFF);            }        }    }} static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,                                       SingleChannelElement *sce,                                       const float lambda){    int q, w, w2, g, start = 0;    int i, j;    int idx;    TrellisPath paths[TRELLIS_STAGES][TRELLIS_STATES];    int bandaddr[TRELLIS_STAGES];    int minq;    float mincost;    float q0f = FLT_MAX, q1f = 0.0f, qnrgf = 0.0f;    int q0, q1, qcnt = 0;     for (i = 0; i < 1024; i++) {        float t = fabsf(sce->coeffs[i]);        if (t > 0.0f) {            q0f = FFMIN(q0f, t);            q1f = FFMAX(q1f, t);            qnrgf += t*t;            qcnt++;        }    }     if (!qcnt) {        memset(sce->sf_idx, 0, sizeof(sce->sf_idx));        memset(sce->zeroes, 1, sizeof(sce->zeroes));        return;    }     //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped    q0 = av_clip(coef2minsf(q0f), 0, SCALE_MAX_POS-1);    //maximum scalefactor index is when maximum coefficient after quantizing is still not zero    q1 = av_clip(coef2maxsf(q1f), 1, SCALE_MAX_POS);    if (q1 - q0 > 60) {        int q0low  = q0;        int q1high = q1;        //minimum scalefactor index is when maximum nonzero coefficient after quantizing is not clipped        int qnrg = av_clip_uint8(log2f(sqrtf(qnrgf/qcnt))*4 - 31 + SCALE_ONE_POS - SCALE_DIV_512);        q1 = qnrg + 30;        q0 = qnrg - 30;        if (q0 < q0low) {            q1 += q0low - q0;            q0  = q0low;        } else if (q1 > q1high) {            q0 -= q1 - q1high;            q1  = q1high;        }    }    // q0 == q1 isn't really a legal situation    if (q0 == q1) {        // the following is indirect but guarantees q1 != q0 && q1 near q0        q1 = av_clip(q0+1, 1, SCALE_MAX_POS);        q0 = av_clip(q1-1, 0, SCALE_MAX_POS - 1);    }     for (i = 0; i < TRELLIS_STATES; i++) {        paths[0][i].cost    = 0.0f;        paths[0][i].prev    = -1;    }    for (j = 1; j < TRELLIS_STAGES; j++) {        for (i = 0; i < TRELLIS_STATES; i++) {            paths[j][i].cost    = INFINITY;            paths[j][i].prev    = -2;        }    }    idx = 1;    abs_pow34_v(s->scoefs, sce->coeffs, 1024);    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {        start = w*128;        for (g = 0; g < sce->ics.num_swb; g++) {            const float *coefs = &sce->coeffs[start];            float qmin, qmax;            int nz = 0;             bandaddr[idx] = w * 16 + g;            qmin = INT_MAX;            qmax = 0.0f;            for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {                FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];                if (band->energy <= band->threshold || band->threshold == 0.0f) {                    sce->zeroes[(w+w2)*16+g] = 1;                    continue;                }                sce->zeroes[(w+w2)*16+g] = 0;                nz = 1;                for (i = 0; i < sce->ics.swb_sizes[g]; i++) {                    float t = fabsf(coefs[w2*128+i]);                    if (t > 0.0f)                        qmin = FFMIN(qmin, t);                    qmax = FFMAX(qmax, t);                }            }            if (nz) {                int minscale, maxscale;                float minrd = INFINITY;                float maxval;                //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped                minscale = coef2minsf(qmin);                //maximum scalefactor index is when maximum coefficient after quantizing is still not zero                maxscale = coef2maxsf(qmax);                minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);                maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);                if (minscale == maxscale) {                    maxscale = av_clip(minscale+1, 1, TRELLIS_STATES);                    minscale = av_clip(maxscale-1, 0, TRELLIS_STATES - 1);                }                maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start);                for (q = minscale; q < maxscale; q++) {                    float dist = 0;                    int cb = find_min_book(maxval, sce->sf_idx[w*16+g]);                    for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {                        FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];                        dist += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],                                                   q + q0, cb, lambda / band->threshold, INFINITY, NULL, NULL, 0);                    }                    minrd = FFMIN(minrd, dist);                     for (i = 0; i < q1 - q0; i++) {                        float cost;                        cost = paths[idx - 1][i].cost + dist                               + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];                        if (cost < paths[idx][q].cost) {                            paths[idx][q].cost    = cost;                            paths[idx][q].prev    = i;                        }                    }                }            } else {                for (q = 0; q < q1 - q0; q++) {                    paths[idx][q].cost = paths[idx - 1][q].cost + 1;                    paths[idx][q].prev = q;                }            }            sce->zeroes[w*16+g] = !nz;            start += sce->ics.swb_sizes[g];            idx++;        }    }    idx--;    mincost = paths[idx][0].cost;    minq    = 0;    for (i = 1; i < TRELLIS_STATES; i++) {        if (paths[idx][i].cost < mincost) {            mincost = paths[idx][i].cost;            minq = i;        }    }    while (idx) {        sce->sf_idx[bandaddr[idx]] = minq + q0;        minq = FFMAX(paths[idx][minq].prev, 0);        idx--;    }    //set the same quantizers inside window groups    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])        for (g = 0; g < sce->ics.num_swb; g++)            for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)                sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];} static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,                                       SingleChannelElement *sce,                                       const float lambda){    int start = 0, i, w, w2, g;    int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels * (lambda / 120.f);    float dists[128] = { 0 }, uplims[128] = { 0 };    float maxvals[128];    int fflag, minscaler;    int its  = 0;    int allz = 0;    float minthr = INFINITY;     // for values above this the decoder might end up in an endless loop    // due to always having more bits than what can be encoded.    destbits = FFMIN(destbits, 5800);    //some heuristic to determine initial quantizers will reduce search time    //determine zero bands and upper limits    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {        start = 0;        for (g = 0; g < sce->ics.num_swb; g++) {            int nz = 0;            float uplim = 0.0f, energy = 0.0f;            for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {                FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];                uplim += band->threshold;                energy += band->energy;                if (band->energy <= band->threshold || band->threshold == 0.0f) {                    sce->zeroes[(w+w2)*16+g] = 1;                    continue;                }                nz = 1;            }            uplims[w*16+g] = uplim *512;            sce->band_type[w*16+g] = 0;            sce->zeroes[w*16+g] = !nz;            if (nz)                minthr = FFMIN(minthr, uplim);            allz |= nz;            start += sce->ics.swb_sizes[g];        }    }    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {        for (g = 0; g < sce->ics.num_swb; g++) {            if (sce->zeroes[w*16+g]) {                sce->sf_idx[w*16+g] = SCALE_ONE_POS;                continue;            }            sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2f(uplims[w*16+g]/minthr)*4,59);        }    }     if (!allz)        return;    abs_pow34_v(s->scoefs, sce->coeffs, 1024);    ff_quantize_band_cost_cache_init(s);     for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {        start = w*128;        for (g = 0; g < sce->ics.num_swb; g++) {            const float *scaled = s->scoefs + start;            maxvals[w*16+g] = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled);            start += sce->ics.swb_sizes[g];        }    }     //perform two-loop search    //outer loop - improve quality    do {        int tbits, qstep;        minscaler = sce->sf_idx[0];        //inner loop - quantize spectrum to fit into given number of bits        qstep = its ? 1 : 32;        do {            int prev = -1;            tbits = 0;            for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {                start = w*128;                for (g = 0; g < sce->ics.num_swb; g++) {                    const float *coefs = sce->coeffs + start;                    const float *scaled = s->scoefs + start;                    int bits = 0;                    int cb;                    float dist = 0.0f;                     if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {                        start += sce->ics.swb_sizes[g];                        continue;                    }                    minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);                    cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);                    for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {                        int b;                        dist += quantize_band_cost_cached(s, w + w2, g,                                                          coefs + w2*128,                                                          scaled + w2*128,                                                          sce->ics.swb_sizes[g],                                                          sce->sf_idx[w*16+g],                                                          cb, 1.0f, INFINITY,                                                          &b, NULL, 0);                        bits += b;                    }                    dists[w*16+g] = dist - bits;                    if (prev != -1) {                        bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];                    }

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