Merge the AAC encoder from SoC svn. It is still considered experimental.

Originally committed as revision 19375 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 1037 insertions, 0 deletions

diff --git a/libavcodec/aaccoder.c b/libavcodec/aaccoder.c
new file mode 100644
index 0000000000..763d3b90dd
--- /dev/null
+++ b/libavcodec/aaccoder.c
@@ -0,0 +1,1037 @@
+/*
+ * 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 libavcodec/aaccoder.c
+ * AAC coefficients encoder
+ */
+
+/***********************************
+ *              TODOs:
+ * speedup quantizer selection
+ * add sane pulse detection
+ ***********************************/
+
+#include "avcodec.h"
+#include "put_bits.h"
+#include "aac.h"
+#include "aacenc.h"
+#include "aactab.h"
+
+/** bits needed to code codebook run value for long windows */
+static const uint8_t run_value_bits_long[64] = {
+     5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,
+     5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5, 10,
+    10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
+    10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 15
+};
+
+/** bits needed to code codebook run value for short windows */
+static const uint8_t run_value_bits_short[16] = {
+    3, 3, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6, 6, 6, 9
+};
+
+static const uint8_t* run_value_bits[2] = {
+    run_value_bits_long, run_value_bits_short
+};
+
+
+/**
+ * Quantize one coefficient.
+ * @return absolute value of the quantized coefficient
+ * @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
+ */
+static av_always_inline int quant(float coef, const float Q)
+{
+    return pow(coef * Q, 0.75) + 0.4054;
+}
+
+static void quantize_bands(int (*out)[2], const float *in, const float *scaled, int size, float Q34, int is_signed, int maxval)
+{
+    int i;
+    double qc;
+    for (i = 0; i < size; i++) {
+        qc = scaled[i] * Q34;
+        out[i][0] = (int)FFMIN((int)qc, maxval);
+        out[i][1] = (int)FFMIN((int)(qc + 0.4054), maxval);
+        if (is_signed && in[i] < 0.0f) {
+            out[i][0] = -out[i][0];
+            out[i][1] = -out[i][1];
+        }
+    }
+}
+
+static void abs_pow34_v(float *out, const float* in, const int size)
+{
+#ifndef USE_REALLY_FULL_SEARCH
+    int i;
+    for (i = 0; i < size; i++) {
+        out[i] = pow(fabsf(in[i]), 0.75);
+    }
+#endif /* USE_REALLY_FULL_SEARCH */
+}
+
+static av_always_inline int quant2(float coef, const float Q)
+{
+    return pow(coef * Q, 0.75);
+}
+
+static const uint8_t aac_cb_range [12] = {0, 3, 3, 3, 3, 9, 9, 8, 8, 13, 13, 17};
+static const uint8_t aac_cb_maxval[12] = {0, 1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 16};
+
+/**
+ * Calculate rate distortion cost for quantizing with given codebook
+ *
+ * @return quantization distortion
+ */
+static float quantize_band_cost(struct AACEncContext *s, const float *in, const float *scaled, int size, int scale_idx, int cb,
+                                 const float lambda, const float uplim, int *bits)
+{
+    const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
+    const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
+    const float CLIPPED_ESCAPE = 165140.0f*IQ;
+    int i, j, k;
+    float cost = 0;
+    const int dim = cb < FIRST_PAIR_BT ? 4 : 2;
+    int resbits = 0;
+#ifndef USE_REALLY_FULL_SEARCH
+    const float  Q34 = pow(Q, 0.75);
+    const int range = aac_cb_range[cb];
+    const int maxval = aac_cb_maxval[cb];
+    int offs[4];
+#endif /* USE_REALLY_FULL_SEARCH */
+
+    if(!cb){
+        for(i = 0; i < size; i++)
+            cost += in[i]*in[i]*lambda;
+        return cost;
+    }
+#ifndef USE_REALLY_FULL_SEARCH
+    offs[0] = 1;
+    for(i = 1; i < dim; i++)
+        offs[i] = offs[i-1]*range;
+    quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
+#endif /* USE_REALLY_FULL_SEARCH */
+    for(i = 0; i < size; i += dim){
+        float mincost;
+        int minidx = 0;
+        int minbits = 0;
+        const float *vec;
+#ifndef USE_REALLY_FULL_SEARCH
+        int (*quants)[2] = &s->qcoefs[i];
+        mincost = 0.0f;
+        for(j = 0; j < dim; j++){
+            mincost += in[i+j]*in[i+j]*lambda;
+        }
+        minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
+        minbits = ff_aac_spectral_bits[cb-1][minidx];
+        mincost += minbits;
+        for(j = 0; j < (1<<dim); j++){
+            float rd = 0.0f;
+            int curbits;
+            int curidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
+            int same = 0;
+            for(k = 0; k < dim; k++){
+                if((j & (1 << k)) && quants[k][0] == quants[k][1]){
+                    same = 1;
+                    break;
+                }
+            }
+            if(same)
+                continue;
+            for(k = 0; k < dim; k++)
+                curidx += quants[k][!!(j & (1 << k))] * offs[dim - 1 - k];
+            curbits = ff_aac_spectral_bits[cb-1][curidx];
+            vec = &ff_aac_codebook_vectors[cb-1][curidx*dim];
+#else
+        mincost = INFINITY;
+        vec = ff_aac_codebook_vectors[cb-1];
+        for(j = 0; j < ff_aac_spectral_sizes[cb-1]; j++, vec += dim){
+            float rd = 0.0f;
+            int curbits = ff_aac_spectral_bits[cb-1][j];
+#endif /* USE_REALLY_FULL_SEARCH */
+            if(IS_CODEBOOK_UNSIGNED(cb)){
+                for(k = 0; k < dim; k++){
+                    float t = fabsf(in[i+k]);
+                    float di;
+                    //do not code with escape sequence small values
+                    if(vec[k] == 64.0f && t < 39.0f*IQ){
+                        rd = INFINITY;
+                        break;
+                    }
+                    if(vec[k] == 64.0f){//FIXME: slow
+                        if (t >= CLIPPED_ESCAPE) {
+                            di = t - CLIPPED_ESCAPE;
+                            curbits += 21;
+                        }else{
+                            int c = av_clip(quant(t, Q), 0, 8191);
+                            di = t - c*cbrt(c)*IQ;
+                            curbits += av_log2(c)*2 - 4 + 1;
+                        }
+                    }else{
+                        di = t - vec[k]*IQ;
+                    }
+                    if(vec[k] != 0.0f)
+                        curbits++;
+                    rd += di*di*lambda;
+                }
+            }else{
+                for(k = 0; k < dim; k++){
+                    float di = in[i+k] - vec[k]*IQ;
+                    rd += di*di*lambda;
+                }
+            }
+            rd += curbits;
+            if(rd < mincost){
+                mincost = rd;
+                minidx = j;
+                minbits = curbits;
+            }
+        }
+        cost += mincost;
+        resbits += minbits;
+        if(cost >= uplim)
+            return uplim;
+    }
+
+    if(bits)
+        *bits = resbits;
+    return cost;
+}
+
+static void quantize_and_encode_band(struct AACEncContext *s, PutBitContext *pb, const float *in, int size,
+                                     int scale_idx, int cb, const float lambda)
+{
+    const float IQ = ff_aac_pow2sf_tab[200 + scale_idx - SCALE_ONE_POS + SCALE_DIV_512];
+    const float  Q = ff_aac_pow2sf_tab[200 - scale_idx + SCALE_ONE_POS - SCALE_DIV_512];
+    const float CLIPPED_ESCAPE = 165140.0f*IQ;
+    const int dim = (cb < FIRST_PAIR_BT) ? 4 : 2;
+    int i, j, k;
+#ifndef USE_REALLY_FULL_SEARCH
+    const float  Q34 = pow(Q, 0.75);
+    const int range = aac_cb_range[cb];
+    const int maxval = aac_cb_maxval[cb];
+    int offs[4];
+    float *scaled = s->scoefs;
+#endif /* USE_REALLY_FULL_SEARCH */
+
+//START_TIMER
+    if(!cb)
+        return;
+
+#ifndef USE_REALLY_FULL_SEARCH
+    offs[0] = 1;
+    for(i = 1; i < dim; i++)
+        offs[i] = offs[i-1]*range;
+    abs_pow34_v(scaled, in, size);
+    quantize_bands(s->qcoefs, in, scaled, size, Q34, !IS_CODEBOOK_UNSIGNED(cb), maxval);
+#endif /* USE_REALLY_FULL_SEARCH */
+    for(i = 0; i < size; i += dim){
+        float mincost;
+        int minidx = 0;
+        int minbits = 0;
+        const float *vec;
+#ifndef USE_REALLY_FULL_SEARCH
+        int (*quants)[2] = &s->qcoefs[i];
+        mincost = 0.0f;
+        for(j = 0; j < dim; j++){
+            mincost += in[i+j]*in[i+j]*lambda;
+        }
+        minidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
+        minbits = ff_aac_spectral_bits[cb-1][minidx];
+        mincost += minbits;
+        for(j = 0; j < (1<<dim); j++){
+            float rd = 0.0f;
+            int curbits;
+            int curidx = IS_CODEBOOK_UNSIGNED(cb) ? 0 : 40;
+            int same = 0;
+            for(k = 0; k < dim; k++){
+                if((j & (1 << k)) && quants[k][0] == quants[k][1]){
+                    same = 1;
+                    break;
+                }
+            }
+            if(same)
+                continue;
+            for(k = 0; k < dim; k++)
+                curidx += quants[k][!!(j & (1 << k))] * offs[dim - 1 - k];
+            curbits = ff_aac_spectral_bits[cb-1][curidx];
+            vec = &ff_aac_codebook_vectors[cb-1][curidx*dim];
+#else
+        vec = ff_aac_codebook_vectors[cb-1];
+        mincost = INFINITY;
+        for(j = 0; j < ff_aac_spectral_sizes[cb-1]; j++, vec += dim){
+            float rd = 0.0f;
+            int curbits = ff_aac_spectral_bits[cb-1][j];
+            int curidx = j;
+#endif /* USE_REALLY_FULL_SEARCH */
+            if(IS_CODEBOOK_UNSIGNED(cb)){
+                for(k = 0; k < dim; k++){
+                    float t = fabsf(in[i+k]);
+                    float di;
+                    //do not code with escape sequence small values
+                    if(vec[k] == 64.0f && t < 39.0f*IQ){
+                        rd = INFINITY;
+                        break;
+                    }
+                    if(vec[k] == 64.0f){//FIXME: slow
+                        if (t >= CLIPPED_ESCAPE) {
+                            di = t - CLIPPED_ESCAPE;
+                            curbits += 21;
+                        }else{
+                            int c = av_clip(quant(t, Q), 0, 8191);
+                            di = t - c*cbrt(c)*IQ;
+                            curbits += av_log2(c)*2 - 4 + 1;
+                        }
+                    }else{
+                        di = t - vec[k]*IQ;
+                    }
+                    if(vec[k] != 0.0f)
+                        curbits++;
+                    rd += di*di*lambda;
+                }
+            }else{
+                for(k = 0; k < dim; k++){
+                    float di = in[i+k] - vec[k]*IQ;
+                    rd += di*di*lambda;
+                }
+            }
+            rd += curbits;
+            if(rd < mincost){
+                mincost = rd;
+                minidx = curidx;
+                minbits = curbits;
+            }
+        }
+        put_bits(pb, ff_aac_spectral_bits[cb-1][minidx], ff_aac_spectral_codes[cb-1][minidx]);
+        if(IS_CODEBOOK_UNSIGNED(cb))
+            for(j = 0; j < dim; j++)
+                if(ff_aac_codebook_vectors[cb-1][minidx*dim+j] != 0.0f)
+                    put_bits(pb, 1, in[i+j] < 0.0f);
+        if(cb == ESC_BT){
+            for(j = 0; j < 2; j++){
+                if(ff_aac_codebook_vectors[cb-1][minidx*2+j] == 64.0f){
+                    int coef = av_clip(quant(fabsf(in[i+j]), Q), 0, 8191);
+                    int len = av_log2(coef);
+
+                    put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
+                    put_bits(pb, len, coef & ((1 << len) - 1));
+                }
+            }
+        }
+    }
+//STOP_TIMER("quantize_and_encode")
+}
+
+/**
+ * structure used in optimal codebook search
+ */
+typedef struct BandCodingPath {
+    int prev_idx; ///< pointer to the previous path point
+    int codebook; ///< codebook for coding band run
+    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][12];
+    int w, swb, cb, start, start2, 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 < 12; 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++){
+        start2 = start;
+        size = sce->ics.swb_sizes[swb];
+        if(sce->zeroes[win*16 + swb]){
+            for(cb = 0; cb < 12; 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 < 12; cb++){
+                float cost_stay_here, cost_get_here;
+                float rd = 0.0f;
+                for(w = 0; w < group_len; w++){
+                    FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_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], cb,
+                                             lambda / band->threshold, INFINITY, NULL);
+                }
+                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 < 12; cb++){
+        if(path[max_sfb][cb].cost < path[max_sfb][idx].cost)
+            idx = cb;
+    }
+    ppos = max_sfb;
+    while(ppos > 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--){
+        put_bits(&s->pb, 4, stackcb[i]);
+        count = stackrun[i];
+        memset(sce->zeroes + win*16 + start, !stackcb[i], count);
+        //XXX: memset when band_type is also uint8_t
+        for(j = 0; j < count; j++){
+            sce->band_type[win*16 + start] =  stackcb[i];
+            start++;
+        }
+        while(count >= run_esc){
+            put_bits(&s->pb, run_bits, run_esc);
+            count -= run_esc;
+        }
+        put_bits(&s->pb, run_bits, count);
+    }
+}
+
+static void encode_window_bands_info_fixed(AACEncContext *s, SingleChannelElement *sce,
+                                           int win, int group_len, const float lambda)
+{
+    encode_window_bands_info(s, sce, win, group_len, 1.0f);
+}
+
+
+typedef struct TrellisPath {
+    float cost;
+    int prev;
+    int min_val;
+    int max_val;
+} TrellisPath;
+
+static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
+                                       SingleChannelElement *sce, const float lambda)
+{
+    int q, w, w2, g, start = 0;
+    int i;
+    int idx;
+    TrellisPath paths[256*121];
+    int bandaddr[121];
+    int minq;
+    float mincost;
+
+    for(i = 0; i < 256; i++){
+        paths[i].cost = 0.0f;
+        paths[i].prev = -1;
+        paths[i].min_val = i;
+        paths[i].max_val = i;
+    }
+    for(i = 256; i < 256*121; i++){
+        paths[i].cost = INFINITY;
+        paths[i].prev = -2;
+        paths[i].min_val = INT_MAX;
+        paths[i].max_val = 0;
+    }
+    idx = 256;
+    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 >> 8] = w*16+g;
+            qmin = INT_MAX;
+            qmax = 0.0f;
+            for(w2 = 0; w2 < sce->ics.group_len[w]; w2++){
+                FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_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 = fminf(qmin, t);
+                    qmax = fmaxf(qmax, t);
+                }
+            }
+            if(nz){
+                int minscale, maxscale;
+                float minrd = INFINITY;
+                //minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
+                minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
+                //maximum scalefactor index is when maximum coefficient after quantizing is still not zero
+                maxscale = av_clip_uint8(log2(qmax)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
+                for(q = minscale; q < maxscale; q++){
+                    float dists[12], dist;
+                    memset(dists, 0, sizeof(dists));
+                    for(w2 = 0; w2 < sce->ics.group_len[w]; w2++){
+                        FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
+                        int cb;
+                        for(cb = 0; cb <= ESC_BT; cb++){
+                            dists[cb] += quantize_band_cost(s, coefs + w2*128, s->scoefs + start + w2*128, sce->ics.swb_sizes[g],
+                                                            q, cb, lambda / band->threshold, INFINITY, NULL);
+                        }
+                    }
+                    dist = dists[0];
+                    for(i = 1; i <= ESC_BT; i++)
+                        dist = fminf(dist, dists[i]);
+                    minrd = fminf(minrd, dist);
+
+                    for(i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++){
+                        float cost;
+                        int minv, maxv;
+                        if(isinf(paths[idx - 256 + i].cost))
+                            continue;
+                        cost = paths[idx - 256 + i].cost + dist
+                               + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
+                        minv = FFMIN(paths[idx - 256 + i].min_val, q);
+                        maxv = FFMAX(paths[idx - 256 + i].max_val, q);
+                        if(cost < paths[idx + q].cost && maxv-minv < SCALE_MAX_DIFF){
+                            paths[idx + q].cost = cost;
+                            paths[idx + q].prev = idx - 256 + i;
+                            paths[idx + q].min_val = minv;
+                            paths[idx + q].max_val = maxv;
+                        }
+                    }
+                }
+            }else{
+                for(q = 0; q < 256; q++){
+                    if(!isinf(paths[idx - 256 + q].cost)){
+                        paths[idx + q].cost = paths[idx - 256 + q].cost + 1;
+                        paths[idx + q].prev = idx - 256 + q;
+                        paths[idx + q].min_val = FFMIN(paths[idx - 256 + q].min_val, q);
+                        paths[idx + q].max_val = FFMAX(paths[idx - 256 + q].max_val, q);
+                        continue;
+                    }
+                    for(i = FFMAX(q - SCALE_MAX_DIFF, 0); i < FFMIN(q + SCALE_MAX_DIFF, 256); i++){
+                        float cost;
+                        int minv, maxv;
+                        if(isinf(paths[idx - 256 + i].cost))
+                            continue;
+                        cost = paths[idx - 256 + i].cost + ff_aac_scalefactor_bits[q - i + SCALE_DIFF_ZERO];
+                        minv = FFMIN(paths[idx - 256 + i].min_val, q);
+                        maxv = FFMAX(paths[idx - 256 + i].max_val, q);
+                        if(cost < paths[idx + q].cost && maxv-minv < SCALE_MAX_DIFF){
+                            paths[idx + q].cost = cost;
+                            paths[idx + q].prev = idx - 256 + i;
+                            paths[idx + q].min_val = minv;
+                            paths[idx + q].max_val = maxv;
+                        }
+                    }
+                }
+            }
+            sce->zeroes[w*16+g] = !nz;
+            start += sce->ics.swb_sizes[g];
+            idx += 256;
+        }
+    }
+    idx -= 256;
+    mincost = paths[idx].cost;
+    minq = idx;
+    for(i = 1; i < 256; i++){
+        if(paths[idx + i].cost < mincost){
+            mincost = paths[idx + i].cost;
+            minq = idx + i;
+        }
+    }
+    while(minq >= 256){
+        sce->sf_idx[bandaddr[minq>>8]] = minq & 0xFF;
+        minq = paths[minq].prev;
+    }
+    //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];
+}
+
+/**
+ * two-loop quantizers search taken from ISO 13818-7 Appendix C
+ */
+static void search_for_quantizers_twoloop(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;
+    float dists[128], uplims[128];
+    int fflag, minscaler;
+    int its = 0;
+    int allz = 0;
+    float minthr = INFINITY;
+
+    //XXX: some heuristic to determine initial quantizers will reduce search time
+    memset(dists, 0, sizeof(dists));
+    //determine zero bands and upper limits
+    for(w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]){
+        for(g = 0;  g < sce->ics.num_swb; g++){
+            int nz = 0;
+            float uplim = 0.0f;
+            for(w2 = 0; w2 < sce->ics.group_len[w]; w2++){
+                FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
+                uplim += band->threshold;
+                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->zeroes[w*16+g] = !nz;
+            if(nz)
+                minthr = fminf(minthr, uplim);
+            allz = FFMAX(allz, nz);
+        }
+    }
+    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 + fminf(log2(uplims[w*16+g]/minthr)*4,59);
+        }
+    }
+
+    if(!allz)
+        return;
+    abs_pow34_v(s->scoefs, sce->coeffs, 1024);
+    //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;
+            fflag = 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 mindist = INFINITY;
+                    int minbits = 0;
+
+                    if(sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218)
+                        continue;
+                    minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
+                    for(cb = 0; cb <= ESC_BT; cb++){
+                        float dist = 0.0f;
+                        int bb = 0;
+                        for(w2 = 0; w2 < sce->ics.group_len[w]; w2++){
+                            int b;
+                            dist += quantize_band_cost(s, coefs + w2*128,
+                                                       scaled + w2*128,
+                                                       sce->ics.swb_sizes[g],
+                                                       sce->sf_idx[w*16+g],
+                                                       ESC_BT,
+                                                       1.0,
+                                                       INFINITY,
+                                                       &b);
+                            bb += b;
+                        }
+                        if(dist < mindist){
+                            mindist = dist;
+                            minbits = bb;
+                        }
+                    }
+                    dists[w*16+g] = mindist - minbits;
+                    bits = minbits;
+                    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)
+                qstep = 1;
+            if(sce->sf_idx[0] >= 217)break;
+        }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]){
+            start = w*128;
+            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)
+                    sce->sf_idx[w*16+g]--;
+                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;
+            }
+        }
+        its++;
+    }while(fflag && its < 10);
+}
+
+static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
+                                       SingleChannelElement *sce, const float lambda)
+{
+    int start = 0, i, w, w2, g;
+    float uplim[128], maxq[128];
+    int minq, maxsf;
+    float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
+    int last = 0, lastband = 0, curband = 0;
+    float avg_energy = 0.0;
+    if(sce->ics.num_windows == 1){
+        start = 0;
+        for(i = 0; i < 1024; i++){
+            if(i - start >= sce->ics.swb_sizes[curband]){
+                start += sce->ics.swb_sizes[curband];
+                curband++;
+            }
+            if(sce->coeffs[i]){
+                avg_energy += sce->coeffs[i] * sce->coeffs[i];
+                last = i;
+                lastband = curband;
+            }
+        }
+    }else{
+        for(w = 0; w < 8; w++){
+            const float *coeffs = sce->coeffs + w*128;
+            start = 0;
+            for(i = 0; i < 128; i++){
+                if(i - start >= sce->ics.swb_sizes[curband]){
+                    start += sce->ics.swb_sizes[curband];
+                    curband++;
+                }
+                if(coeffs[i]){
+                    avg_energy += coeffs[i] * coeffs[i];
+                    last = FFMAX(last, i);
+                    lastband = FFMAX(lastband, curband);
+                }
+            }
+        }
+    }
+    last++;
+    avg_energy /= last;
+    if(avg_energy == 0.0f){
+        for(i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
+            sce->sf_idx[i] = SCALE_ONE_POS;
+        return;
+    }
+    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++){
+            float *coefs = sce->coeffs + start;
+            const int size = sce->ics.swb_sizes[g];
+            int start2 = start, end2 = start + size, peakpos = start;
+            float maxval = -1, thr = 0.0f, t;
+            maxq[w*16+g] = 0.0f;
+            if(g > lastband){
+                maxq[w*16+g] = 0.0f;
+                start += size;
+                for(w2 = 0; w2 < sce->ics.group_len[w]; w2++)
+                    memset(coefs + w2*128, 0, sizeof(coefs[0])*size);
+                continue;
+            }
+            for(w2 = 0; w2 < sce->ics.group_len[w]; w2++){
+                for(i = 0; i < size; i++){
+                    float t = coefs[w2*128+i]*coefs[w2*128+i];
+                    maxq[w*16+g] = fmaxf(maxq[w*16+g], fabsf(coefs[w2*128 + i]));
+                    thr += t;
+                    if(sce->ics.num_windows == 1 && maxval < t){
+                        maxval = t;
+                        peakpos = start+i;
+                    }
+                }
+            }
+            if(sce->ics.num_windows == 1){
+                start2 = FFMAX(peakpos - 2, start2);
+                end2   = FFMIN(peakpos + 3, end2);
+            }else{
+                start2 -= start;
+                end2   -= start;
+            }
+            start += size;
+            thr = pow(thr / (avg_energy * (end2 - start2)), 0.3 + 0.1*(lastband - g) / lastband);
+            t = 1.0 - (1.0 * start2 / last);
+            uplim[w*16+g] = distfact / (1.4 * thr + t*t*t + 0.075);
+        }
+    }
+    memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
+    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;
+            const float *scaled = s->scoefs + start;
+            const int size = sce->ics.swb_sizes[g];
+            int scf, prev_scf, step;
+            int min_scf = 0, max_scf = 255;
+            float curdiff;
+            if(maxq[w*16+g] < 21.544){
+                sce->zeroes[w*16+g] = 1;
+                start += size;
+                continue;
+            }
+            sce->zeroes[w*16+g] = 0;
+            scf = prev_scf = av_clip(SCALE_ONE_POS - SCALE_DIV_512 - log2(1/maxq[w*16+g])*16/3, 60, 218);
+            step = 16;
+            for(;;){
+                float dist = 0.0f;
+                int quant_max;
+
+                for(w2 = 0; w2 < sce->ics.group_len[w]; w2++){
+                    int b;
+                    dist += quantize_band_cost(s, coefs + w2*128,
+                                               scaled + w2*128,
+                                               sce->ics.swb_sizes[g],
+                                               scf,
+                                               ESC_BT,
+                                               1.0,
+                                               INFINITY,
+                                               &b);
+                    dist -= b;
+                }
+                dist *= 1.0f/512.0f;
+                quant_max = quant(maxq[w*16+g], ff_aac_pow2sf_tab[200 - scf + SCALE_ONE_POS - SCALE_DIV_512]);
+                if(quant_max >= 8191){ // too much, return to the previous quantizer
+                    sce->sf_idx[w*16+g] = prev_scf;
+                    break;
+                }
+                prev_scf = scf;
+                curdiff = fabsf(dist - uplim[w*16+g]);
+                if(curdiff == 0.0f)
+                    step = 0;
+                else
+                    step = fabsf(log2(curdiff));
+                if(dist > uplim[w*16+g])
+                    step = -step;
+                if(FFABS(step) <= 1 || (step > 0 && scf >= max_scf) || (step < 0 && scf <= min_scf)){
+                    sce->sf_idx[w*16+g] = scf;
+                    break;
+                }
+                scf += step;
+                if(step > 0)
+                    min_scf = scf;
+                else
+                    max_scf = scf;
+            }
+            start += size;
+        }
+    }
+    minq = sce->sf_idx[0] ? sce->sf_idx[0] : INT_MAX;
+    for(i = 1; i < 128; i++){
+        if(!sce->sf_idx[i])
+            sce->sf_idx[i] = sce->sf_idx[i-1];
+        else
+            minq = FFMIN(minq, sce->sf_idx[i]);
+    }
+    if(minq == INT_MAX) minq = 0;
+    minq = FFMIN(minq, SCALE_MAX_POS);
+    maxsf = FFMIN(minq + SCALE_MAX_DIFF, SCALE_MAX_POS);
+    for(i = 126; i >= 0; i--){
+        if(!sce->sf_idx[i])
+            sce->sf_idx[i] = sce->sf_idx[i+1];
+        sce->sf_idx[i] = av_clip(sce->sf_idx[i], minq, maxsf);
+    }
+}
+
+static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
+                                       SingleChannelElement *sce, const float lambda)
+{
+    int start = 0, i, w, w2, g;
+    int minq = 255;
+
+    memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
+    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++){
+            for(w2 = 0; w2 < sce->ics.group_len[w]; w2++){
+                FFPsyBand *band = &s->psy.psy_bands[s->cur_channel*PSY_MAX_BANDS+(w+w2)*16+g];
+                if(band->energy <= band->threshold){
+                    sce->sf_idx[(w+w2)*16+g] = 218;
+                    sce->zeroes[(w+w2)*16+g] = 1;
+                }else{
+                    sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2(band->threshold), 80, 218);
+                    sce->zeroes[(w+w2)*16+g] = 0;
+                }
+                minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
+            }
+        }
+    }
+    for(i = 0; i < 128; i++){
+        sce->sf_idx[i] = 140;//av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
+    }
+    //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_ms(AACEncContext *s, ChannelElement *cpe, const float lambda)
+{
+    int start = 0, i, w, w2, g;
+    float M[128], S[128];
+    float *L34 = s->scoefs, *R34 = s->scoefs + 128, *M34 = s->scoefs + 128*2, *S34 = s->scoefs + 128*3;
+    SingleChannelElement *sce0 = &cpe->ch[0];
+    SingleChannelElement *sce1 = &cpe->ch[1];
+    if(!cpe->common_window)
+        return;
+    for(w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]){
+        for(g = 0;  g < sce0->ics.num_swb; g++){
+            if(!cpe->ch[0].zeroes[w*16+g] && !cpe->ch[1].zeroes[w*16+g]){
+                float dist1 = 0.0f, dist2 = 0.0f;
+                for(w2 = 0; w2 < sce0->ics.group_len[w]; w2++){
+                    FFPsyBand *band0 = &s->psy.psy_bands[(s->cur_channel+0)*PSY_MAX_BANDS+(w+w2)*16+g];
+                    FFPsyBand *band1 = &s->psy.psy_bands[(s->cur_channel+1)*PSY_MAX_BANDS+(w+w2)*16+g];
+                    float minthr = fminf(band0->threshold, band1->threshold);
+                    float maxthr = fmaxf(band0->threshold, band1->threshold);
+                    for(i = 0; i < sce0->ics.swb_sizes[g]; i++){
+                        M[i] = (sce0->coeffs[start+w2*128+i]
+                              + sce1->coeffs[start+w2*128+i])*0.5;
+                        S[i] =  sce0->coeffs[start+w2*128+i]
+                              - sce1->coeffs[start+w2*128+i];
+                    }
+                    abs_pow34_v(L34, sce0->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
+                    abs_pow34_v(R34, sce1->coeffs+start+w2*128, sce0->ics.swb_sizes[g]);
+                    abs_pow34_v(M34, M,                         sce0->ics.swb_sizes[g]);
+                    abs_pow34_v(S34, S,                         sce0->ics.swb_sizes[g]);
+                    dist1 += quantize_band_cost(s, sce0->coeffs + start + w2*128,
+                                                L34,
+                                                sce0->ics.swb_sizes[g],
+                                                sce0->sf_idx[(w+w2)*16+g],
+                                                sce0->band_type[(w+w2)*16+g],
+                                                lambda / band0->threshold, INFINITY, NULL);
+                    dist1 += quantize_band_cost(s, sce1->coeffs + start + w2*128,
+                                                R34,
+                                                sce1->ics.swb_sizes[g],
+                                                sce1->sf_idx[(w+w2)*16+g],
+                                                sce1->band_type[(w+w2)*16+g],
+                                                lambda / band1->threshold, INFINITY, NULL);
+                    dist2 += quantize_band_cost(s, M,
+                                                M34,
+                                                sce0->ics.swb_sizes[g],
+                                                sce0->sf_idx[(w+w2)*16+g],
+                                                sce0->band_type[(w+w2)*16+g],
+                                                lambda / maxthr, INFINITY, NULL);
+                    dist2 += quantize_band_cost(s, S,
+                                                S34,
+                                                sce1->ics.swb_sizes[g],
+                                                sce1->sf_idx[(w+w2)*16+g],
+                                                sce1->band_type[(w+w2)*16+g],
+                                                lambda / minthr, INFINITY, NULL);
+                }
+                cpe->ms_mask[w*16+g] = dist2 < dist1;
+            }
+            start += sce0->ics.swb_sizes[g];
+        }
+    }
+}
+
+AACCoefficientsEncoder ff_aac_coders[] = {
+    {
+        search_for_quantizers_faac,
+        encode_window_bands_info_fixed,
+        quantize_and_encode_band,
+//        search_for_ms,
+    },
+    {
+        search_for_quantizers_anmr,
+        encode_window_bands_info,
+        quantize_and_encode_band,
+//        search_for_ms,
+    },
+    {
+        search_for_quantizers_twoloop,
+        encode_window_bands_info,
+        quantize_and_encode_band,
+//        search_for_ms,
+    },
+    {
+        search_for_quantizers_fast,
+        encode_window_bands_info,
+        quantize_and_encode_band,
+//        search_for_ms,
+    },
+};