Rename ffmpeg-4.2-fit to ffmpeg-4-fit

trunk/3rdparty/ffmpeg-4-fit/libavcodec/aaccoder.c

@@ -0,0 +1,964 @@
+/*
+ * 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;
+
+    s->abs_pow34(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;
+    s->abs_pow34(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;
+    s->abs_pow34(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];
+                    }
+                    tbits += bits;
+                    start += sce->ics.swb_sizes[g];
+                    prev = sce->sf_idx[w*16+g];
+                }
+            }
+            if (tbits > destbits) {
+                for (i = 0; i < 128; i++)
+                    if (sce->sf_idx[i] < 218 - qstep)
+                        sce->sf_idx[i] += qstep;
+            } else {
+                for (i = 0; i < 128; i++)
+                    if (sce->sf_idx[i] > 60 - qstep)
+                        sce->sf_idx[i] -= qstep;
+            }
+            qstep >>= 1;
+            if (!qstep && tbits > destbits*1.02 && sce->sf_idx[0] < 217)
+                qstep = 1;
+        } while (qstep);
+
+        fflag = 0;
+        minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
+
+        for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
+            for (g = 0; g < sce->ics.num_swb; g++) {
+                int prevsc = sce->sf_idx[w*16+g];
+                if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60) {
+                    if (find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]-1))
+                        sce->sf_idx[w*16+g]--;
+                    else //Try to make sure there is some energy in every band
+                        sce->sf_idx[w*16+g]-=2;
+                }
+                sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
+                sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
+                if (sce->sf_idx[w*16+g] != prevsc)
+                    fflag = 1;
+                sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
+            }
+        }
+        its++;
+    } while (fflag && its < 10);
+}
+
+static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)
+{
+    FFPsyBand *band;
+    int w, g, w2, i;
+    int wlen = 1024 / sce->ics.num_windows;
+    int bandwidth, cutoff;
+    float *PNS = &s->scoefs[0*128], *PNS34 = &s->scoefs[1*128];
+    float *NOR34 = &s->scoefs[3*128];
+    uint8_t nextband[128];
+    const float lambda = s->lambda;
+    const float freq_mult = avctx->sample_rate*0.5f/wlen;
+    const float thr_mult = NOISE_LAMBDA_REPLACE*(100.0f/lambda);
+    const float spread_threshold = FFMIN(0.75f, NOISE_SPREAD_THRESHOLD*FFMAX(0.5f, lambda/100.f));
+    const float dist_bias = av_clipf(4.f * 120 / lambda, 0.25f, 4.0f);
+    const float pns_transient_energy_r = FFMIN(0.7f, lambda / 140.f);
+
+    int refbits = avctx->bit_rate * 1024.0 / avctx->sample_rate
+        / ((avctx->flags & AV_CODEC_FLAG_QSCALE) ? 2.0f : avctx->channels)
+        * (lambda / 120.f);
+
+    /** Keep this in sync with twoloop's cutoff selection */
+    float rate_bandwidth_multiplier = 1.5f;
+    int prev = -1000, prev_sf = -1;
+    int frame_bit_rate = (avctx->flags & AV_CODEC_FLAG_QSCALE)
+        ? (refbits * rate_bandwidth_multiplier * avctx->sample_rate / 1024)
+        : (avctx->bit_rate / avctx->channels);
+
+    frame_bit_rate *= 1.15f;
+
+    if (avctx->cutoff > 0) {
+        bandwidth = avctx->cutoff;
+    } else {
+        bandwidth = FFMAX(3000, AAC_CUTOFF_FROM_BITRATE(frame_bit_rate, 1, avctx->sample_rate));
+    }
+
+    cutoff = bandwidth * 2 * wlen / avctx->sample_rate;
+
+    memcpy(sce->band_alt, sce->band_type, sizeof(sce->band_type));
+    ff_init_nextband_map(sce, nextband);
+    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
+        int wstart = w*128;
+        for (g = 0; g < sce->ics.num_swb; g++) {
+            int noise_sfi;
+            float dist1 = 0.0f, dist2 = 0.0f, noise_amp;
+            float pns_energy = 0.0f, pns_tgt_energy, energy_ratio, dist_thresh;
+            float sfb_energy = 0.0f, threshold = 0.0f, spread = 2.0f;
+            float min_energy = -1.0f, max_energy = 0.0f;
+            const int start = wstart+sce->ics.swb_offset[g];
+            const float freq = (start-wstart)*freq_mult;
+            const float freq_boost = FFMAX(0.88f*freq/NOISE_LOW_LIMIT, 1.0f);
+            if (freq < NOISE_LOW_LIMIT || (start-wstart) >= cutoff) {
+                if (!sce->zeroes[w*16+g])
+                    prev_sf = sce->sf_idx[w*16+g];
+                continue;
+            }
+            for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
+                band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
+                sfb_energy += band->energy;
+                spread     = FFMIN(spread, band->spread);
+                threshold  += band->threshold;
+                if (!w2) {
+                    min_energy = max_energy = band->energy;
+                } else {
+                    min_energy = FFMIN(min_energy, band->energy);
+                    max_energy = FFMAX(max_energy, band->energy);
+                }
+            }
+
+            /* Ramps down at ~8000Hz and loosens the dist threshold */
+            dist_thresh = av_clipf(2.5f*NOISE_LOW_LIMIT/freq, 0.5f, 2.5f) * dist_bias;
+
+            /* PNS is acceptable when all of these are true:
+             * 1. high spread energy (noise-like band)
+             * 2. near-threshold energy (high PE means the random nature of PNS content will be noticed)
+             * 3. on short window groups, all windows have similar energy (variations in energy would be destroyed by PNS)
+             *
+             * At this stage, point 2 is relaxed for zeroed bands near the noise threshold (hole avoidance is more important)
+             */
+            if ((!sce->zeroes[w*16+g] && !ff_sfdelta_can_remove_band(sce, nextband, prev_sf, w*16+g)) ||
+                ((sce->zeroes[w*16+g] || !sce->band_alt[w*16+g]) && sfb_energy < threshold*sqrtf(1.0f/freq_boost)) || spread < spread_threshold ||
+                (!sce->zeroes[w*16+g] && sce->band_alt[w*16+g] && sfb_energy > threshold*thr_mult*freq_boost) ||
+                min_energy < pns_transient_energy_r * max_energy ) {
+                sce->pns_ener[w*16+g] = sfb_energy;
+                if (!sce->zeroes[w*16+g])
+                    prev_sf = sce->sf_idx[w*16+g];
+                continue;
+            }
+
+            pns_tgt_energy = sfb_energy*FFMIN(1.0f, spread*spread);
+            noise_sfi = av_clip(roundf(log2f(pns_tgt_energy)*2), -100, 155); /* Quantize */
+            noise_amp = -ff_aac_pow2sf_tab[noise_sfi + POW_SF2_ZERO];    /* Dequantize */
+            if (prev != -1000) {
+                int noise_sfdiff = noise_sfi - prev + SCALE_DIFF_ZERO;
+                if (noise_sfdiff < 0 || noise_sfdiff > 2*SCALE_MAX_DIFF) {
+                    if (!sce->zeroes[w*16+g])
+                        prev_sf = sce->sf_idx[w*16+g];
+                    continue;
+                }
+            }
+            for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
+                float band_energy, scale, pns_senergy;
+                const int start_c = (w+w2)*128+sce->ics.swb_offset[g];
+                band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
+                for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
+                    s->random_state  = lcg_random(s->random_state);
+                    PNS[i] = s->random_state;
+                }
+                band_energy = s->fdsp->scalarproduct_float(PNS, PNS, sce->ics.swb_sizes[g]);
+                scale = noise_amp/sqrtf(band_energy);
+                s->fdsp->vector_fmul_scalar(PNS, PNS, scale, sce->ics.swb_sizes[g]);
+                pns_senergy = s->fdsp->scalarproduct_float(PNS, PNS, sce->ics.swb_sizes[g]);
+                pns_energy += pns_senergy;
+                s->abs_pow34(NOR34, &sce->coeffs[start_c], sce->ics.swb_sizes[g]);
+                s->abs_pow34(PNS34, PNS, sce->ics.swb_sizes[g]);
+                dist1 += quantize_band_cost(s, &sce->coeffs[start_c],
+                                            NOR34,
+                                            sce->ics.swb_sizes[g],
+                                            sce->sf_idx[(w+w2)*16+g],
+                                            sce->band_alt[(w+w2)*16+g],
+                                            lambda/band->threshold, INFINITY, NULL, NULL, 0);
+                /* Estimate rd on average as 5 bits for SF, 4 for the CB, plus spread energy * lambda/thr */
+                dist2 += band->energy/(band->spread*band->spread)*lambda*dist_thresh/band->threshold;
+            }
+            if (g && sce->band_type[w*16+g-1] == NOISE_BT) {
+                dist2 += 5;
+            } else {
+                dist2 += 9;
+            }
+            energy_ratio = pns_tgt_energy/pns_energy; /* Compensates for quantization error */
+            sce->pns_ener[w*16+g] = energy_ratio*pns_tgt_energy;
+            if (sce->zeroes[w*16+g] || !sce->band_alt[w*16+g] || (energy_ratio > 0.85f && energy_ratio < 1.25f && dist2 < dist1)) {
+                sce->band_type[w*16+g] = NOISE_BT;
+                sce->zeroes[w*16+g] = 0;
+                prev = noise_sfi;
+            } else {
+                if (!sce->zeroes[w*16+g])
+                    prev_sf = sce->sf_idx[w*16+g];
+            }
+        }
+    }
+}
+
+static void mark_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)
+{
+    FFPsyBand *band;
+    int w, g, w2;
+    int wlen = 1024 / sce->ics.num_windows;
+    int bandwidth, cutoff;
+    const float lambda = s->lambda;
+    const float freq_mult = avctx->sample_rate*0.5f/wlen;
+    const float spread_threshold = FFMIN(0.75f, NOISE_SPREAD_THRESHOLD*FFMAX(0.5f, lambda/100.f));
+    const float pns_transient_energy_r = FFMIN(0.7f, lambda / 140.f);
+
+    int refbits = avctx->bit_rate * 1024.0 / avctx->sample_rate
+        / ((avctx->flags & AV_CODEC_FLAG_QSCALE) ? 2.0f : avctx->channels)
+        * (lambda / 120.f);
+
+    /** Keep this in sync with twoloop's cutoff selection */
+    float rate_bandwidth_multiplier = 1.5f;
+    int frame_bit_rate = (avctx->flags & AV_CODEC_FLAG_QSCALE)
+        ? (refbits * rate_bandwidth_multiplier * avctx->sample_rate / 1024)
+        : (avctx->bit_rate / avctx->channels);
+
+    frame_bit_rate *= 1.15f;
+
+    if (avctx->cutoff > 0) {
+        bandwidth = avctx->cutoff;
+    } else {
+        bandwidth = FFMAX(3000, AAC_CUTOFF_FROM_BITRATE(frame_bit_rate, 1, avctx->sample_rate));
+    }
+
+    cutoff = bandwidth * 2 * wlen / avctx->sample_rate;
+
+    memcpy(sce->band_alt, sce->band_type, sizeof(sce->band_type));
+    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
+        for (g = 0; g < sce->ics.num_swb; g++) {
+            float sfb_energy = 0.0f, threshold = 0.0f, spread = 2.0f;
+            float min_energy = -1.0f, max_energy = 0.0f;
+            const int start = sce->ics.swb_offset[g];
+            const float freq = start*freq_mult;
+            const float freq_boost = FFMAX(0.88f*freq/NOISE_LOW_LIMIT, 1.0f);
+            if (freq < NOISE_LOW_LIMIT || start >= cutoff) {
+                sce->can_pns[w*16+g] = 0;
+                continue;
+            }
+            for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
+                band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
+                sfb_energy += band->energy;
+                spread     = FFMIN(spread, band->spread);
+                threshold  += band->threshold;
+                if (!w2) {
+                    min_energy = max_energy = band->energy;
+                } else {
+                    min_energy = FFMIN(min_energy, band->energy);
+                    max_energy = FFMAX(max_energy, band->energy);
+                }
+            }
+
+            /* PNS is acceptable when all of these are true:
+             * 1. high spread energy (noise-like band)
+             * 2. near-threshold energy (high PE means the random nature of PNS content will be noticed)
+             * 3. on short window groups, all windows have similar energy (variations in energy would be destroyed by PNS)
+             */
+            sce->pns_ener[w*16+g] = sfb_energy;
+            if (sfb_energy < threshold*sqrtf(1.5f/freq_boost) || spread < spread_threshold || min_energy < pns_transient_energy_r * max_energy) {
+                sce->can_pns[w*16+g] = 0;
+            } else {
+                sce->can_pns[w*16+g] = 1;
+            }
+        }
+    }
+}
+
+static void search_for_ms(AACEncContext *s, ChannelElement *cpe)
+{
+    int start = 0, i, w, w2, g, sid_sf_boost, prev_mid, prev_side;
+    uint8_t nextband0[128], nextband1[128];
+    float *M   = s->scoefs + 128*0, *S   = s->scoefs + 128*1;
+    float *L34 = s->scoefs + 128*2, *R34 = s->scoefs + 128*3;
+    float *M34 = s->scoefs + 128*4, *S34 = s->scoefs + 128*5;
+    const float lambda = s->lambda;
+    const float mslambda = FFMIN(1.0f, lambda / 120.f);
+    SingleChannelElement *sce0 = &cpe->ch[0];
+    SingleChannelElement *sce1 = &cpe->ch[1];
+    if (!cpe->common_window)
+        return;
+
+    /** Scout out next nonzero bands */
+    ff_init_nextband_map(sce0, nextband0);
+    ff_init_nextband_map(sce1, nextband1);
+
+    prev_mid = sce0->sf_idx[0];
+    prev_side = sce1->sf_idx[0];
+    for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
+        start = 0;
+        for (g = 0; g < sce0->ics.num_swb; g++) {
+            float bmax = bval2bmax(g * 17.0f / sce0->ics.num_swb) / 0.0045f;
+            if (!cpe->is_mask[w*16+g])
+                cpe->ms_mask[w*16+g] = 0;
+            if (!sce0->zeroes[w*16+g] && !sce1->zeroes[w*16+g] && !cpe->is_mask[w*16+g]) {
+                float Mmax = 0.0f, Smax = 0.0f;
+
+                /* Must compute mid/side SF and book for the whole window group */
+                for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
+                    for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
+                        M[i] = (sce0->coeffs[start+(w+w2)*128+i]
+                              + sce1->coeffs[start+(w+w2)*128+i]) * 0.5;
+                        S[i] =  M[i]
+                              - sce1->coeffs[start+(w+w2)*128+i];
+                    }
+                    s->abs_pow34(M34, M, sce0->ics.swb_sizes[g]);
+                    s->abs_pow34(S34, S, sce0->ics.swb_sizes[g]);
+                    for (i = 0; i < sce0->ics.swb_sizes[g]; i++ ) {
+                        Mmax = FFMAX(Mmax, M34[i]);
+                        Smax = FFMAX(Smax, S34[i]);
+                    }
+                }
+
+                for (sid_sf_boost = 0; sid_sf_boost < 4; sid_sf_boost++) {
+                    float dist1 = 0.0f, dist2 = 0.0f;
+                    int B0 = 0, B1 = 0;
+                    int minidx;
+                    int mididx, sididx;
+                    int midcb, sidcb;
+
+                    minidx = FFMIN(sce0->sf_idx[w*16+g], sce1->sf_idx[w*16+g]);
+                    mididx = av_clip(minidx, 0, SCALE_MAX_POS - SCALE_DIV_512);
+                    sididx = av_clip(minidx - sid_sf_boost * 3, 0, SCALE_MAX_POS - SCALE_DIV_512);
+                    if (sce0->band_type[w*16+g] != NOISE_BT && sce1->band_type[w*16+g] != NOISE_BT
+                        && (   !ff_sfdelta_can_replace(sce0, nextband0, prev_mid, mididx, w*16+g)
+                            || !ff_sfdelta_can_replace(sce1, nextband1, prev_side, sididx, w*16+g))) {
+                        /* scalefactor range violation, bad stuff, will decrease quality unacceptably */
+                        continue;
+                    }
+
+                    midcb = find_min_book(Mmax, mididx);
+                    sidcb = find_min_book(Smax, sididx);
+
+                    /* No CB can be zero */
+                    midcb = FFMAX(1,midcb);
+                    sidcb = FFMAX(1,sidcb);
+
+                    for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
+                        FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
+                        FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];
+                        float minthr = FFMIN(band0->threshold, band1->threshold);
+                        int b1,b2,b3,b4;
+                        for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
+                            M[i] = (sce0->coeffs[start+(w+w2)*128+i]
+                                  + sce1->coeffs[start+(w+w2)*128+i]) * 0.5;
+                            S[i] =  M[i]
+                                  - sce1->coeffs[start+(w+w2)*128+i];
+                        }
+
+                        s->abs_pow34(L34, sce0->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
+                        s->abs_pow34(R34, sce1->coeffs+start+(w+w2)*128, sce0->ics.swb_sizes[g]);
+                        s->abs_pow34(M34, M,                         sce0->ics.swb_sizes[g]);
+                        s->abs_pow34(S34, S,                         sce0->ics.swb_sizes[g]);
+                        dist1 += quantize_band_cost(s, &sce0->coeffs[start + (w+w2)*128],
+                                                    L34,
+                                                    sce0->ics.swb_sizes[g],
+                                                    sce0->sf_idx[w*16+g],
+                                                    sce0->band_type[w*16+g],
+                                                    lambda / band0->threshold, INFINITY, &b1, NULL, 0);
+                        dist1 += quantize_band_cost(s, &sce1->coeffs[start + (w+w2)*128],
+                                                    R34,
+                                                    sce1->ics.swb_sizes[g],
+                                                    sce1->sf_idx[w*16+g],
+                                                    sce1->band_type[w*16+g],
+                                                    lambda / band1->threshold, INFINITY, &b2, NULL, 0);
+                        dist2 += quantize_band_cost(s, M,
+                                                    M34,
+                                                    sce0->ics.swb_sizes[g],
+                                                    mididx,
+                                                    midcb,
+                                                    lambda / minthr, INFINITY, &b3, NULL, 0);
+                        dist2 += quantize_band_cost(s, S,
+                                                    S34,
+                                                    sce1->ics.swb_sizes[g],
+                                                    sididx,
+                                                    sidcb,
+                                                    mslambda / (minthr * bmax), INFINITY, &b4, NULL, 0);
+                        B0 += b1+b2;
+                        B1 += b3+b4;
+                        dist1 -= b1+b2;
+                        dist2 -= b3+b4;
+                    }
+                    cpe->ms_mask[w*16+g] = dist2 <= dist1 && B1 < B0;
+                    if (cpe->ms_mask[w*16+g]) {
+                        if (sce0->band_type[w*16+g] != NOISE_BT && sce1->band_type[w*16+g] != NOISE_BT) {
+                            sce0->sf_idx[w*16+g] = mididx;
+                            sce1->sf_idx[w*16+g] = sididx;
+                            sce0->band_type[w*16+g] = midcb;
+                            sce1->band_type[w*16+g] = sidcb;
+                        } else if ((sce0->band_type[w*16+g] != NOISE_BT) ^ (sce1->band_type[w*16+g] != NOISE_BT)) {
+                            /* ms_mask unneeded, and it confuses some decoders */
+                            cpe->ms_mask[w*16+g] = 0;
+                        }
+                        break;
+                    } else if (B1 > B0) {
+                        /* More boost won't fix this */
+                        break;
+                    }
+                }
+            }
+            if (!sce0->zeroes[w*16+g] && sce0->band_type[w*16+g] < RESERVED_BT)
+                prev_mid = sce0->sf_idx[w*16+g];
+            if (!sce1->zeroes[w*16+g] && !cpe->is_mask[w*16+g] && sce1->band_type[w*16+g] < RESERVED_BT)
+                prev_side = sce1->sf_idx[w*16+g];
+            start += sce0->ics.swb_sizes[g];
+        }
+    }
+}
+
+const AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = {
+    [AAC_CODER_ANMR] = {
+        search_for_quantizers_anmr,
+        encode_window_bands_info,
+        quantize_and_encode_band,
+        ff_aac_encode_tns_info,
+        ff_aac_encode_ltp_info,
+        ff_aac_encode_main_pred,
+        ff_aac_adjust_common_pred,
+        ff_aac_adjust_common_ltp,
+        ff_aac_apply_main_pred,
+        ff_aac_apply_tns,
+        ff_aac_update_ltp,
+        ff_aac_ltp_insert_new_frame,
+        set_special_band_scalefactors,
+        search_for_pns,
+        mark_pns,
+        ff_aac_search_for_tns,
+        ff_aac_search_for_ltp,
+        search_for_ms,
+        ff_aac_search_for_is,
+        ff_aac_search_for_pred,
+    },
+    [AAC_CODER_TWOLOOP] = {
+        search_for_quantizers_twoloop,
+        codebook_trellis_rate,
+        quantize_and_encode_band,
+        ff_aac_encode_tns_info,
+        ff_aac_encode_ltp_info,
+        ff_aac_encode_main_pred,
+        ff_aac_adjust_common_pred,
+        ff_aac_adjust_common_ltp,
+        ff_aac_apply_main_pred,
+        ff_aac_apply_tns,
+        ff_aac_update_ltp,
+        ff_aac_ltp_insert_new_frame,
+        set_special_band_scalefactors,
+        search_for_pns,
+        mark_pns,
+        ff_aac_search_for_tns,
+        ff_aac_search_for_ltp,
+        search_for_ms,
+        ff_aac_search_for_is,
+        ff_aac_search_for_pred,
+    },
+    [AAC_CODER_FAST] = {
+        search_for_quantizers_fast,
+        codebook_trellis_rate,
+        quantize_and_encode_band,
+        ff_aac_encode_tns_info,
+        ff_aac_encode_ltp_info,
+        ff_aac_encode_main_pred,
+        ff_aac_adjust_common_pred,
+        ff_aac_adjust_common_ltp,
+        ff_aac_apply_main_pred,
+        ff_aac_apply_tns,
+        ff_aac_update_ltp,
+        ff_aac_ltp_insert_new_frame,
+        set_special_band_scalefactors,
+        search_for_pns,
+        mark_pns,
+        ff_aac_search_for_tns,
+        ff_aac_search_for_ltp,
+        search_for_ms,
+        ff_aac_search_for_is,
+        ff_aac_search_for_pred,
+    },
+};