| 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 | */ |
| 31 | extern const uint16_t ff_ac3_bap_bits[16]; |
| 32 | |
| 33 | typedef 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 | * Calculate the maximum MSB of the absolute value of each element in an |
| 47 | * array of int16_t. |
| 48 | * @param src input array |
| 49 | * constraints: align 16. values must be in range [-32767,32767] |
| 50 | * @param len number of values in the array |
| 51 | * constraints: multiple of 16 greater than 0 |
| 52 | * @return a value with the same MSB as max(abs(src[])) |
| 53 | */ |
| 54 | int (*ac3_max_msb_abs_int16)(const int16_t *src, int len); |
| 55 | |
| 56 | /** |
| 57 | * Left-shift each value in an array of int16_t by a specified amount. |
| 58 | * @param src input array |
| 59 | * constraints: align 16 |
| 60 | * @param len number of values in the array |
| 61 | * constraints: multiple of 32 greater than 0 |
| 62 | * @param shift left shift amount |
| 63 | * constraints: range [0,15] |
| 64 | */ |
| 65 | void (*ac3_lshift_int16)(int16_t *src, unsigned int len, unsigned int shift); |
| 66 | |
| 67 | /** |
| 68 | * Right-shift each value in an array of int32_t by a specified amount. |
| 69 | * @param src input array |
| 70 | * constraints: align 16 |
| 71 | * @param len number of values in the array |
| 72 | * constraints: multiple of 16 greater than 0 |
| 73 | * @param shift right shift amount |
| 74 | * constraints: range [0,31] |
| 75 | */ |
| 76 | void (*ac3_rshift_int32)(int32_t *src, unsigned int len, unsigned int shift); |
| 77 | |
| 78 | /** |
| 79 | * Convert an array of float in range [-1.0,1.0] to int32_t with range |
| 80 | * [-(1<<24),(1<<24)] |
| 81 | * |
| 82 | * @param dst destination array of int32_t. |
| 83 | * constraints: 16-byte aligned |
| 84 | * @param src source array of float. |
| 85 | * constraints: 16-byte aligned |
| 86 | * @param len number of elements to convert. |
| 87 | * constraints: multiple of 32 greater than zero |
| 88 | */ |
| 89 | void (*float_to_fixed24)(int32_t *dst, const float *src, unsigned int len); |
| 90 | |
| 91 | /** |
| 92 | * Calculate bit allocation pointers. |
| 93 | * The SNR is the difference between the masking curve and the signal. AC-3 |
| 94 | * uses this value for each frequency bin to allocate bits. The snroffset |
| 95 | * parameter is a global adjustment to the SNR for all bins. |
| 96 | * |
| 97 | * @param[in] mask masking curve |
| 98 | * @param[in] psd signal power for each frequency bin |
| 99 | * @param[in] start starting bin location |
| 100 | * @param[in] end ending bin location |
| 101 | * @param[in] snr_offset SNR adjustment |
| 102 | * @param[in] floor noise floor |
| 103 | * @param[in] bap_tab look-up table for bit allocation pointers |
| 104 | * @param[out] bap bit allocation pointers |
| 105 | */ |
| 106 | void (*bit_alloc_calc_bap)(int16_t *mask, int16_t *psd, int start, int end, |
| 107 | int snr_offset, int floor, |
| 108 | const uint8_t *bap_tab, uint8_t *bap); |
| 109 | |
| 110 | /** |
| 111 | * Update bap counts using the supplied array of bap. |
| 112 | * |
| 113 | * @param[out] mant_cnt bap counts for 1 block |
| 114 | * @param[in] bap array of bap, pointing to start coef bin |
| 115 | * @param[in] len number of elements to process |
| 116 | */ |
| 117 | void (*update_bap_counts)(uint16_t mant_cnt[16], uint8_t *bap, int len); |
| 118 | |
| 119 | /** |
| 120 | * Calculate the number of bits needed to encode a set of mantissas. |
| 121 | * |
| 122 | * @param[in] mant_cnt bap counts for all blocks |
| 123 | * @return mantissa bit count |
| 124 | */ |
| 125 | int (*compute_mantissa_size)(uint16_t mant_cnt[6][16]); |
| 126 | |
| 127 | void (*extract_exponents)(uint8_t *exp, int32_t *coef, int nb_coefs); |
| 128 | |
| 129 | void (*sum_square_butterfly_int32)(int64_t sum[4], const int32_t *coef0, |
| 130 | const int32_t *coef1, int len); |
| 131 | |
| 132 | void (*sum_square_butterfly_float)(float sum[4], const float *coef0, |
| 133 | const float *coef1, int len); |
| 134 | |
| 135 | void (*downmix)(float **samples, float (*matrix)[2], int out_ch, |
| 136 | int in_ch, int len); |
| 137 | |
| 138 | void (*downmix_fixed)(int32_t **samples, int16_t (*matrix)[2], int out_ch, |
| 139 | int in_ch, int len); |
| 140 | |
| 141 | /** |
| 142 | * Apply symmetric window in 16-bit fixed-point. |
| 143 | * @param output destination array |
| 144 | * constraints: 16-byte aligned |
| 145 | * @param input source array |
| 146 | * constraints: 16-byte aligned |
| 147 | * @param window window array |
| 148 | * constraints: 16-byte aligned, at least len/2 elements |
| 149 | * @param len full window length |
| 150 | * constraints: multiple of ? greater than zero |
| 151 | */ |
| 152 | void (*apply_window_int16)(int16_t *output, const int16_t *input, |
| 153 | const int16_t *window, unsigned int len); |
| 154 | } AC3DSPContext; |
| 155 | |
| 156 | void ff_ac3dsp_init (AC3DSPContext *c, int bit_exact); |
| 157 | void ff_ac3dsp_init_arm(AC3DSPContext *c, int bit_exact); |
| 158 | void ff_ac3dsp_init_x86(AC3DSPContext *c, int bit_exact); |
| 159 | void ff_ac3dsp_init_mips(AC3DSPContext *c, int bit_exact); |
| 160 | |
| 161 | #endif /* AVCODEC_AC3DSP_H */ |