245 lines
8.8 KiB
C
245 lines
8.8 KiB
C
/*
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* AAC encoder utilities
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* Copyright (C) 2015 Rostislav Pehlivanov
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* AAC encoder utilities
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* @author Rostislav Pehlivanov ( atomnuker gmail com )
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*/
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#ifndef AVCODEC_AACENC_UTILS_H
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#define AVCODEC_AACENC_UTILS_H
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#include "aac.h"
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#include "aac_tablegen_decl.h"
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#include "aacenctab.h"
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#define ROUND_STANDARD 0.4054f
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#define ROUND_TO_ZERO 0.1054f
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#define C_QUANT 0.4054f
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static inline void abs_pow34_v(float *out, const float *in, const int size)
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{
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int i;
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for (i = 0; i < size; i++) {
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float a = fabsf(in[i]);
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out[i] = sqrtf(a * sqrtf(a));
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}
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}
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/**
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* Quantize one coefficient.
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* @return absolute value of the quantized coefficient
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* @see 3GPP TS26.403 5.6.2 "Scalefactor determination"
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*/
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static inline int quant(float coef, const float Q, const float rounding)
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{
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float a = coef * Q;
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return sqrtf(a * sqrtf(a)) + rounding;
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}
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static inline void quantize_bands(int *out, const float *in, const float *scaled,
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int size, float Q34, int is_signed, int maxval,
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const float rounding)
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{
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int i;
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double qc;
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for (i = 0; i < size; i++) {
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qc = scaled[i] * Q34;
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out[i] = (int)FFMIN(qc + rounding, (double)maxval);
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if (is_signed && in[i] < 0.0f) {
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out[i] = -out[i];
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}
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}
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}
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static inline float find_max_val(int group_len, int swb_size, const float *scaled)
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{
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float maxval = 0.0f;
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int w2, i;
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for (w2 = 0; w2 < group_len; w2++) {
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for (i = 0; i < swb_size; i++) {
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maxval = FFMAX(maxval, scaled[w2*128+i]);
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}
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}
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return maxval;
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}
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static inline int find_min_book(float maxval, int sf)
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{
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float Q = ff_aac_pow2sf_tab[POW_SF2_ZERO - sf + SCALE_ONE_POS - SCALE_DIV_512];
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float Q34 = sqrtf(Q * sqrtf(Q));
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int qmaxval, cb;
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qmaxval = maxval * Q34 + C_QUANT;
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if (qmaxval >= (FF_ARRAY_ELEMS(aac_maxval_cb)))
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cb = 11;
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else
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cb = aac_maxval_cb[qmaxval];
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return cb;
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}
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static inline float find_form_factor(int group_len, int swb_size, float thresh,
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const float *scaled, float nzslope) {
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const float iswb_size = 1.0f / swb_size;
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const float iswb_sizem1 = 1.0f / (swb_size - 1);
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const float ethresh = thresh;
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float form = 0.0f, weight = 0.0f;
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int w2, i;
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for (w2 = 0; w2 < group_len; w2++) {
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float e = 0.0f, e2 = 0.0f, var = 0.0f, maxval = 0.0f;
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float nzl = 0;
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for (i = 0; i < swb_size; i++) {
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float s = fabsf(scaled[w2*128+i]);
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maxval = FFMAX(maxval, s);
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e += s;
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e2 += s *= s;
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/* We really don't want a hard non-zero-line count, since
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* even below-threshold lines do add up towards band spectral power.
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* So, fall steeply towards zero, but smoothly
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*/
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if (s >= ethresh) {
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nzl += 1.0f;
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} else {
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nzl += powf(s / ethresh, nzslope);
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}
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}
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if (e2 > thresh) {
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float frm;
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e *= iswb_size;
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/** compute variance */
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for (i = 0; i < swb_size; i++) {
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float d = fabsf(scaled[w2*128+i]) - e;
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var += d*d;
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}
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var = sqrtf(var * iswb_sizem1);
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e2 *= iswb_size;
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frm = e / FFMIN(e+4*var,maxval);
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form += e2 * sqrtf(frm) / FFMAX(0.5f,nzl);
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weight += e2;
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}
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}
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if (weight > 0) {
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return form / weight;
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} else {
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return 1.0f;
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}
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}
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/** Return the minimum scalefactor where the quantized coef does not clip. */
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static inline uint8_t coef2minsf(float coef)
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{
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return av_clip_uint8(log2f(coef)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
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}
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/** Return the maximum scalefactor where the quantized coef is not zero. */
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static inline uint8_t coef2maxsf(float coef)
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{
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return av_clip_uint8(log2f(coef)*4 + 6 + SCALE_ONE_POS - SCALE_DIV_512);
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}
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/*
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* Returns the closest possible index to an array of float values, given a value.
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*/
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static inline int quant_array_idx(const float val, const float *arr, const int num)
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{
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int i, index = 0;
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float quant_min_err = INFINITY;
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for (i = 0; i < num; i++) {
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float error = (val - arr[i])*(val - arr[i]);
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if (error < quant_min_err) {
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quant_min_err = error;
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index = i;
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}
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}
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return index;
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}
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/**
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* approximates exp10f(-3.0f*(0.5f + 0.5f * cosf(FFMIN(b,15.5f) / 15.5f)))
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*/
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static av_always_inline float bval2bmax(float b)
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{
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return 0.001f + 0.0035f * (b*b*b) / (15.5f*15.5f*15.5f);
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}
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/*
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* linear congruential pseudorandom number generator, copied from the decoder
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*/
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static inline int lcg_random(unsigned previous_val)
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{
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union { unsigned u; int s; } v = { previous_val * 1664525u + 1013904223 };
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return v.s;
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}
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#define ERROR_IF(cond, ...) \
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if (cond) { \
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av_log(avctx, AV_LOG_ERROR, __VA_ARGS__); \
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return AVERROR(EINVAL); \
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}
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#define WARN_IF(cond, ...) \
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if (cond) { \
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av_log(avctx, AV_LOG_WARNING, __VA_ARGS__); \
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}
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#define AAC_OPT_SET(e_opt, p_opt, bypass, name) \
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ERROR_IF ((e_opt)->name == 1 && (p_opt)->name == OPT_BANNED, \
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"Profile %i does not allow %s\n", avctx->profile, #name); \
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ERROR_IF ((e_opt)->name == 0 && (p_opt)->name == OPT_REQUIRED, \
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"Option %s is a requirement for this profile (%i)\n", \
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#name, avctx->profile); \
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if ((e_opt)->name == 1 && (p_opt)->name == OPT_NEEDS_MAIN && \
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avctx->profile == FF_PROFILE_AAC_LOW) { \
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WARN_IF(1, "Profile %i does not allow for %s, setting profile to " \
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"\"aac_main\"(%i)\n", avctx->profile, #name, \
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FF_PROFILE_AAC_MAIN); \
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avctx->profile = FF_PROFILE_AAC_MAIN; \
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p_opt = &aacenc_profiles[FF_PROFILE_AAC_MAIN].opts; \
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} \
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if ((e_opt)->name == 1 && (p_opt)->name == OPT_NEEDS_LTP && \
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avctx->profile == FF_PROFILE_AAC_LOW) { \
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WARN_IF(1, "Profile %i does not allow for %s, setting profile to " \
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"\"aac_ltp\"(%i)\n", avctx->profile, #name, \
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FF_PROFILE_AAC_LTP); \
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avctx->profile = FF_PROFILE_AAC_LTP; \
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p_opt = &aacenc_profiles[FF_PROFILE_AAC_LTP].opts; \
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} \
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if ((e_opt)->name == OPT_AUTO) { \
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if ((p_opt)->name == OPT_BANNED) { \
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(e_opt)->name = 0; \
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} else if ((p_opt)->name == OPT_NEEDS_LTP) { \
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(e_opt)->name = 0; \
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} else if ((p_opt)->name == OPT_NEEDS_MAIN) { \
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(e_opt)->name = 0; \
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} else if ((p_opt)->name == OPT_REQUIRED) { \
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(e_opt)->name = 1; \
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} else if (bypass) { \
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(e_opt)->name = (e_opt)->name; \
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} else { \
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(e_opt)->name = (p_opt)->name; \
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} \
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} \
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av_log(avctx, AV_LOG_VERBOSE, "Option %s set to %i\n", #name, (e_opt)->name);
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#endif /* AVCODEC_AACENC_UTILS_H */
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