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c816d3d042
The codebooks each consist of small number of values repeated in groups of 2 or 4. Storing the codebooks as a packed list of 2- or 4-bit indexes into a table reduces their size substantially (from 7.5k to 1.5k), resulting in less cache pressure. For the band types with sign bits in the bitstream, storing the number and position of non-zero codebook values using a few bits avoids multiple get_bits() calls and floating-point comparisons which gcc handles miserably. Some float/int type punning also avoids gcc brain damage. Overall speedup 20-35% on Cortex-A8, 20% on Core i7. Originally committed as revision 21188 to svn://svn.ffmpeg.org/ffmpeg/trunk
83 lines
2.5 KiB
C
83 lines
2.5 KiB
C
/*
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* AAC data declarations
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* Copyright (c) 2005-2006 Oded Shimon ( ods15 ods15 dyndns org )
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* Copyright (c) 2006-2007 Maxim Gavrilov ( maxim.gavrilov gmail com )
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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 libavcodec/aactab.h
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* AAC data declarations
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* @author Oded Shimon ( ods15 ods15 dyndns org )
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* @author Maxim Gavrilov ( maxim.gavrilov gmail com )
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*/
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#ifndef AVCODEC_AACTAB_H
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#define AVCODEC_AACTAB_H
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#include "libavutil/mem.h"
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#include "aac.h"
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#include <stdint.h>
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/* NOTE:
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* Tables in this file are used by the AAC decoder and will be used by the AAC
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* encoder.
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*/
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/* @name window coefficients
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* @{
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*/
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DECLARE_ALIGNED(16, extern float, ff_aac_kbd_long_1024[1024]);
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DECLARE_ALIGNED(16, extern float, ff_aac_kbd_short_128[128]);
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// @}
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/* @name number of scalefactor window bands for long and short transform windows respectively
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* @{
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*/
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extern const uint8_t ff_aac_num_swb_1024[];
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extern const uint8_t ff_aac_num_swb_128 [];
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// @}
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extern const uint8_t ff_aac_pred_sfb_max [];
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extern const uint32_t ff_aac_scalefactor_code[121];
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extern const uint8_t ff_aac_scalefactor_bits[121];
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extern const uint16_t * const ff_aac_spectral_codes[11];
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extern const uint8_t * const ff_aac_spectral_bits [11];
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extern const uint16_t ff_aac_spectral_sizes[11];
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extern const float *ff_aac_codebook_vectors[];
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extern const float *ff_aac_codebook_vector_vals[];
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extern const uint16_t *ff_aac_codebook_vector_idx[];
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extern const uint16_t * const ff_swb_offset_1024[13];
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extern const uint16_t * const ff_swb_offset_128 [13];
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extern const uint8_t ff_tns_max_bands_1024[13];
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extern const uint8_t ff_tns_max_bands_128 [13];
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#if CONFIG_HARDCODED_TABLES
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extern const float ff_aac_pow2sf_tab[428];
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#else
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extern float ff_aac_pow2sf_tab[428];
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#endif /* CONFIG_HARDCODED_TABLES */
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#endif /* AVCODEC_AACTAB_H */
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