1/* 2 * AC-3 DSP functions 3 * Copyright (c) 2011 Justin Ruggles 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#ifndef AVCODEC_AC3DSP_H 23#define AVCODEC_AC3DSP_H 24 25#include <stdint.h> 26 27/** 28 * Number of mantissa bits written for each bap value. 29 * bap values with fractional bits are set to 0 and are calculated separately. 30 */ 31extern const uint16_t ff_ac3_bap_bits[16]; 32 33typedef struct AC3DSPContext { 34 /** 35 * Set each encoded exponent in a block to the minimum of itself and the 36 * exponents in the same frequency bin of up to 5 following blocks. 37 * @param exp pointer to the start of the current block of exponents. 38 * constraints: align 16 39 * @param num_reuse_blocks number of blocks that will reuse exponents from the current block. 40 * constraints: range 0 to 5 41 * @param nb_coefs number of frequency coefficients. 42 */ 43 void (*ac3_exponent_min)(uint8_t *exp, int num_reuse_blocks, int nb_coefs); 44 45 /** 46 * Convert an array of float in range [-1.0,1.0] to int32_t with range 47 * [-(1<<24),(1<<24)] 48 * 49 * @param dst destination array of int32_t. 50 * constraints: 16-byte aligned 51 * @param src source array of float. 52 * constraints: 16-byte aligned 53 * @param len number of elements to convert. 54 * constraints: multiple of 32 greater than zero 55 */ 56 void (*float_to_fixed24)(int32_t *dst, const float *src, unsigned int len); 57 58 /** 59 * Calculate bit allocation pointers. 60 * The SNR is the difference between the masking curve and the signal. AC-3 61 * uses this value for each frequency bin to allocate bits. The snroffset 62 * parameter is a global adjustment to the SNR for all bins. 63 * 64 * @param[in] mask masking curve 65 * @param[in] psd signal power for each frequency bin 66 * @param[in] start starting bin location 67 * @param[in] end ending bin location 68 * @param[in] snr_offset SNR adjustment 69 * @param[in] floor noise floor 70 * @param[in] bap_tab look-up table for bit allocation pointers 71 * @param[out] bap bit allocation pointers 72 */ 73 void (*bit_alloc_calc_bap)(int16_t *mask, int16_t *psd, int start, int end, 74 int snr_offset, int floor, 75 const uint8_t *bap_tab, uint8_t *bap); 76 77 /** 78 * Update bap counts using the supplied array of bap. 79 * 80 * @param[out] mant_cnt bap counts for 1 block 81 * @param[in] bap array of bap, pointing to start coef bin 82 * @param[in] len number of elements to process 83 */ 84 void (*update_bap_counts)(uint16_t mant_cnt[16], uint8_t *bap, int len); 85 86 /** 87 * Calculate the number of bits needed to encode a set of mantissas. 88 * 89 * @param[in] mant_cnt bap counts for all blocks 90 * @return mantissa bit count 91 */ 92 int (*compute_mantissa_size)(uint16_t mant_cnt[6][16]); 93 94 void (*extract_exponents)(uint8_t *exp, int32_t *coef, int nb_coefs); 95 96 void (*sum_square_butterfly_int32)(int64_t sum[4], const int32_t *coef0, 97 const int32_t *coef1, int len); 98 99 void (*sum_square_butterfly_float)(float sum[4], const float *coef0, 100 const float *coef1, int len); 101 102 int out_channels; 103 int in_channels; 104 void (*downmix)(float **samples, float **matrix, int len); 105 void (*downmix_fixed)(int32_t **samples, int16_t **matrix, int len); 106} AC3DSPContext; 107 108void ff_ac3dsp_init (AC3DSPContext *c, int bit_exact); 109void ff_ac3dsp_init_arm(AC3DSPContext *c, int bit_exact); 110void ff_ac3dsp_init_x86(AC3DSPContext *c, int bit_exact); 111void ff_ac3dsp_init_mips(AC3DSPContext *c, int bit_exact); 112 113void ff_ac3dsp_downmix(AC3DSPContext *c, float **samples, float **matrix, 114 int out_ch, int in_ch, int len); 115void ff_ac3dsp_downmix_fixed(AC3DSPContext *c, int32_t **samples, int16_t **matrix, 116 int out_ch, int in_ch, int len); 117 118void ff_ac3dsp_set_downmix_x86(AC3DSPContext *c); 119 120#endif /* AVCODEC_AC3DSP_H */ 121