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Diffstat (limited to 'libavcodec/aacenc_utils.h')
| -rw-r--r-- | libavcodec/aacenc_utils.h | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/libavcodec/aacenc_utils.h b/libavcodec/aacenc_utils.h new file mode 100644 index 0000000000..0ab15a3e5e --- /dev/null +++ b/libavcodec/aacenc_utils.h @@ -0,0 +1,152 @@ +/* + * 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 "aac.h" +#include "aac_tablegen_decl.h" +#include "aacenctab.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)); + } +} + +/** + * 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, float Q34, int is_signed, int maxval, + const float rounding) +{ + int i; + double qc; + for (i = 0; i < size; i++) { + qc = scaled[i] * Q34; + out[i] = (int)FFMIN(qc + rounding, (double)maxval); + if (is_signed && in[i] < 0.0f) { + out[i] = -out[i]; + } + } +} + +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 Q = ff_aac_pow2sf_tab[POW_SF2_ZERO - sf + SCALE_ONE_POS - SCALE_DIV_512]; + float Q34 = sqrtf(Q * sqrtf(Q)); + int qmaxval, cb; + qmaxval = maxval * Q34 + C_QUANT; + if (qmaxval == 0) cb = 0; + else if (qmaxval == 1) cb = 1; + else if (qmaxval == 2) cb = 3; + else if (qmaxval <= 4) cb = 5; + else if (qmaxval <= 7) cb = 7; + else if (qmaxval <= 12) cb = 9; + else cb = 11; + return cb; +} + +/** 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; +} + +/* + * linear congruential pseudorandom number generator, copied from the decoder + */ +static 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 */ |