For #1659, #307, add ffmpeg-4.2-fit for rtc

trunk/3rdparty/ffmpeg-4.2-fit/libavcodec/aacenc_utils.h

@@ -0,0 +1,279 @@
+/*
+ * AAC encoder utilities
+ * Copyright (C) 2015 Rostislav Pehlivanov
+ *
+ * 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 encoder utilities
+ * @author Rostislav Pehlivanov ( atomnuker gmail com )
+ */
+
+#ifndef AVCODEC_AACENC_UTILS_H
+#define AVCODEC_AACENC_UTILS_H
+
+#include "libavutil/ffmath.h"
+#include "aac.h"
+#include "aacenctab.h"
+#include "aactab.h"
+
+#define ROUND_STANDARD 0.4054f
+#define ROUND_TO_ZERO 0.1054f
+#define C_QUANT 0.4054f
+
+static inline void abs_pow34_v(float *out, const float *in, const int size)
+{
+    int i;
+    for (i = 0; i < size; i++) {
+        float a = fabsf(in[i]);
+        out[i] = sqrtf(a * sqrtf(a));
+    }
+}
+
+static inline float pos_pow34(float a)
+{
+    return sqrtf(a * sqrtf(a));
+}
+
+/**
+ * Quantize one coefficient.
+ * @return absolute value of the quantized coefficient
+ * @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
+ */
+static inline int quant(float coef, const float Q, const float rounding)
+{
+    float a = coef * Q;
+    return sqrtf(a * sqrtf(a)) + rounding;
+}
+
+static inline void quantize_bands(int *out, const float *in, const float *scaled,
+                                  int size, int is_signed, int maxval, const float Q34,
+                                  const float rounding)
+{
+    int i;
+    for (i = 0; i < size; i++) {
+        float qc = scaled[i] * Q34;
+        int tmp = (int)FFMIN(qc + rounding, (float)maxval);
+        if (is_signed && in[i] < 0.0f) {
+            tmp = -tmp;
+        }
+        out[i] = tmp;
+    }
+}
+
+static inline float find_max_val(int group_len, int swb_size, const float *scaled)
+{
+    float maxval = 0.0f;
+    int w2, i;
+    for (w2 = 0; w2 < group_len; w2++) {
+        for (i = 0; i < swb_size; i++) {
+            maxval = FFMAX(maxval, scaled[w2*128+i]);
+        }
+    }
+    return maxval;
+}
+
+static inline int find_min_book(float maxval, int sf)
+{
+    float Q34 = ff_aac_pow34sf_tab[POW_SF2_ZERO - sf + SCALE_ONE_POS - SCALE_DIV_512];
+    int qmaxval, cb;
+    qmaxval = maxval * Q34 + C_QUANT;
+    if (qmaxval >= (FF_ARRAY_ELEMS(aac_maxval_cb)))
+        cb = 11;
+    else
+        cb = aac_maxval_cb[qmaxval];
+    return cb;
+}
+
+static inline float find_form_factor(int group_len, int swb_size, float thresh,
+                                     const float *scaled, float nzslope) {
+    const float iswb_size = 1.0f / swb_size;
+    const float iswb_sizem1 = 1.0f / (swb_size - 1);
+    const float ethresh = thresh;
+    float form = 0.0f, weight = 0.0f;
+    int w2, i;
+    for (w2 = 0; w2 < group_len; w2++) {
+        float e = 0.0f, e2 = 0.0f, var = 0.0f, maxval = 0.0f;
+        float nzl = 0;
+        for (i = 0; i < swb_size; i++) {
+            float s = fabsf(scaled[w2*128+i]);
+            maxval = FFMAX(maxval, s);
+            e += s;
+            e2 += s *= s;
+            /* We really don't want a hard non-zero-line count, since
+             * even below-threshold lines do add up towards band spectral power.
+             * So, fall steeply towards zero, but smoothly
+             */
+            if (s >= ethresh) {
+                nzl += 1.0f;
+            } else {
+                if (nzslope == 2.f)
+                    nzl += (s / ethresh) * (s / ethresh);
+                else
+                    nzl += ff_fast_powf(s / ethresh, nzslope);
+            }
+        }
+        if (e2 > thresh) {
+            float frm;
+            e *= iswb_size;
+
+            /** compute variance */
+            for (i = 0; i < swb_size; i++) {
+                float d = fabsf(scaled[w2*128+i]) - e;
+                var += d*d;
+            }
+            var = sqrtf(var * iswb_sizem1);
+
+            e2 *= iswb_size;
+            frm = e / FFMIN(e+4*var,maxval);
+            form += e2 * sqrtf(frm) / FFMAX(0.5f,nzl);
+            weight += e2;
+        }
+    }
+    if (weight > 0) {
+        return form / weight;
+    } else {
+        return 1.0f;
+    }
+}
+
+/** Return the minimum scalefactor where the quantized coef does not clip. */
+static inline uint8_t coef2minsf(float coef)
+{
+    return av_clip_uint8(log2f(coef)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
+}
+
+/** Return the maximum scalefactor where the quantized coef is not zero. */
+static inline uint8_t coef2maxsf(float coef)
+{
+    return av_clip_uint8(log2f(coef)*4 +  6 + SCALE_ONE_POS - SCALE_DIV_512);
+}
+
+/*
+ * Returns the closest possible index to an array of float values, given a value.
+ */
+static inline int quant_array_idx(const float val, const float *arr, const int num)
+{
+    int i, index = 0;
+    float quant_min_err = INFINITY;
+    for (i = 0; i < num; i++) {
+        float error = (val - arr[i])*(val - arr[i]);
+        if (error < quant_min_err) {
+            quant_min_err = error;
+            index = i;
+        }
+    }
+    return index;
+}
+
+/**
+ * approximates exp10f(-3.0f*(0.5f + 0.5f * cosf(FFMIN(b,15.5f) / 15.5f)))
+ */
+static av_always_inline float bval2bmax(float b)
+{
+    return 0.001f + 0.0035f * (b*b*b) / (15.5f*15.5f*15.5f);
+}
+
+/*
+ * Compute a nextband map to be used with SF delta constraint utilities.
+ * The nextband array should contain 128 elements, and positions that don't
+ * map to valid, nonzero bands of the form w*16+g (with w being the initial
+ * window of the window group, only) are left indetermined.
+ */
+static inline void ff_init_nextband_map(const SingleChannelElement *sce, uint8_t *nextband)
+{
+    unsigned char prevband = 0;
+    int w, g;
+    /** Just a safe default */
+    for (g = 0; g < 128; g++)
+        nextband[g] = g;
+
+    /** Now really navigate the nonzero band chain */
+    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->band_type[w*16+g] < RESERVED_BT)
+                prevband = nextband[prevband] = w*16+g;
+        }
+    }
+    nextband[prevband] = prevband; /* terminate */
+}
+
+/*
+ * Updates nextband to reflect a removed band (equivalent to
+ * calling ff_init_nextband_map after marking a band as zero)
+ */
+static inline void ff_nextband_remove(uint8_t *nextband, int prevband, int band)
+{
+    nextband[prevband] = nextband[band];
+}
+
+/*
+ * Checks whether the specified band could be removed without inducing
+ * scalefactor delta that violates SF delta encoding constraints.
+ * prev_sf has to be the scalefactor of the previous nonzero, nonspecial
+ * band, in encoding order, or negative if there was no such band.
+ */
+static inline int ff_sfdelta_can_remove_band(const SingleChannelElement *sce,
+    const uint8_t *nextband, int prev_sf, int band)
+{
+    return prev_sf >= 0
+        && sce->sf_idx[nextband[band]] >= (prev_sf - SCALE_MAX_DIFF)
+        && sce->sf_idx[nextband[band]] <= (prev_sf + SCALE_MAX_DIFF);
+}
+
+/*
+ * Checks whether the specified band's scalefactor could be replaced
+ * with another one without violating SF delta encoding constraints.
+ * prev_sf has to be the scalefactor of the previous nonzero, nonsepcial
+ * band, in encoding order, or negative if there was no such band.
+ */
+static inline int ff_sfdelta_can_replace(const SingleChannelElement *sce,
+    const uint8_t *nextband, int prev_sf, int new_sf, int band)
+{
+    return new_sf >= (prev_sf - SCALE_MAX_DIFF)
+        && new_sf <= (prev_sf + SCALE_MAX_DIFF)
+        && sce->sf_idx[nextband[band]] >= (new_sf - SCALE_MAX_DIFF)
+        && sce->sf_idx[nextband[band]] <= (new_sf + SCALE_MAX_DIFF);
+}
+
+/**
+ * linear congruential pseudorandom number generator
+ *
+ * @param   previous_val    pointer to the current state of the generator
+ *
+ * @return  Returns a 32-bit pseudorandom integer
+ */
+static av_always_inline int lcg_random(unsigned previous_val)
+{
+    union { unsigned u; int s; } v = { previous_val * 1664525u + 1013904223 };
+    return v.s;
+}
+
+#define ERROR_IF(cond, ...) \
+    if (cond) { \
+        av_log(avctx, AV_LOG_ERROR, __VA_ARGS__); \
+        return AVERROR(EINVAL); \
+    }
+
+#define WARN_IF(cond, ...) \
+    if (cond) { \
+        av_log(avctx, AV_LOG_WARNING, __VA_ARGS__); \
+    }
+
+#endif /* AVCODEC_AACENC_UTILS_H */