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#include "libavutil/avassert.h" 23#include "avcodec.h" 24#include "ac3.h" 25#include "ac3dsp.h" 26#include "mathops.h" 27 28static void ac3_exponent_min_c(uint8_t *exp, int num_reuse_blocks, int nb_coefs) 29{ 30 int blk, i; 31 32 if (!num_reuse_blocks) 33 return; 34 35 for (i = 0; i < nb_coefs; i++) { 36 uint8_t min_exp = *exp; 37 uint8_t *exp1 = exp + 256; 38 for (blk = 0; blk < num_reuse_blocks; blk++) { 39 uint8_t next_exp = *exp1; 40 if (next_exp < min_exp) 41 min_exp = next_exp; 42 exp1 += 256; 43 } 44 *exp++ = min_exp; 45 } 46} 47 48static int ac3_max_msb_abs_int16_c(const int16_t *src, int len) 49{ 50 int i, v = 0; 51 for (i = 0; i < len; i++) 52 v |= abs(src[i]); 53 return v; 54} 55 56static void ac3_lshift_int16_c(int16_t *src, unsigned int len, 57 unsigned int shift) 58{ 59 uint32_t *src32 = (uint32_t *)src; 60 const uint32_t mask = ~(((1 << shift) - 1) << 16); 61 int i; 62 len >>= 1; 63 for (i = 0; i < len; i += 8) { 64 src32[i ] = (src32[i ] << shift) & mask; 65 src32[i+1] = (src32[i+1] << shift) & mask; 66 src32[i+2] = (src32[i+2] << shift) & mask; 67 src32[i+3] = (src32[i+3] << shift) & mask; 68 src32[i+4] = (src32[i+4] << shift) & mask; 69 src32[i+5] = (src32[i+5] << shift) & mask; 70 src32[i+6] = (src32[i+6] << shift) & mask; 71 src32[i+7] = (src32[i+7] << shift) & mask; 72 } 73} 74 75static void ac3_rshift_int32_c(int32_t *src, unsigned int len, 76 unsigned int shift) 77{ 78 do { 79 *src++ >>= shift; 80 *src++ >>= shift; 81 *src++ >>= shift; 82 *src++ >>= shift; 83 *src++ >>= shift; 84 *src++ >>= shift; 85 *src++ >>= shift; 86 *src++ >>= shift; 87 len -= 8; 88 } while (len > 0); 89} 90 91static void float_to_fixed24_c(int32_t *dst, const float *src, unsigned int len) 92{ 93 const float scale = 1 << 24; 94 do { 95 *dst++ = lrintf(*src++ * scale); 96 *dst++ = lrintf(*src++ * scale); 97 *dst++ = lrintf(*src++ * scale); 98 *dst++ = lrintf(*src++ * scale); 99 *dst++ = lrintf(*src++ * scale); 100 *dst++ = lrintf(*src++ * scale); 101 *dst++ = lrintf(*src++ * scale); 102 *dst++ = lrintf(*src++ * scale); 103 len -= 8; 104 } while (len > 0); 105} 106 107static void ac3_bit_alloc_calc_bap_c(int16_t *mask, int16_t *psd, 108 int start, int end, 109 int snr_offset, int floor, 110 const uint8_t *bap_tab, uint8_t *bap) 111{ 112 int bin, band, band_end; 113 114 /* special case, if snr offset is -960, set all bap's to zero */ 115 if (snr_offset == -960) { 116 memset(bap, 0, AC3_MAX_COEFS); 117 return; 118 } 119 120 bin = start; 121 band = ff_ac3_bin_to_band_tab[start]; 122 do { 123 int m = (FFMAX(mask[band] - snr_offset - floor, 0) & 0x1FE0) + floor; 124 band_end = ff_ac3_band_start_tab[++band]; 125 band_end = FFMIN(band_end, end); 126 127 for (; bin < band_end; bin++) { 128 int address = av_clip((psd[bin] - m) >> 5, 0, 63); 129 bap[bin] = bap_tab[address]; 130 } 131 } while (end > band_end); 132} 133 134static void ac3_update_bap_counts_c(uint16_t mant_cnt[16], uint8_t *bap, 135 int len) 136{ 137 while (len-- > 0) 138 mant_cnt[bap[len]]++; 139} 140 141DECLARE_ALIGNED(16, const uint16_t, ff_ac3_bap_bits)[16] = { 142 0, 0, 0, 3, 0, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16 143}; 144 145static int ac3_compute_mantissa_size_c(uint16_t mant_cnt[6][16]) 146{ 147 int blk, bap; 148 int bits = 0; 149 150 for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 151 // bap=1 : 3 mantissas in 5 bits 152 bits += (mant_cnt[blk][1] / 3) * 5; 153 // bap=2 : 3 mantissas in 7 bits 154 // bap=4 : 2 mantissas in 7 bits 155 bits += ((mant_cnt[blk][2] / 3) + (mant_cnt[blk][4] >> 1)) * 7; 156 // bap=3 : 1 mantissa in 3 bits 157 bits += mant_cnt[blk][3] * 3; 158 // bap=5 to 15 : get bits per mantissa from table 159 for (bap = 5; bap < 16; bap++) 160 bits += mant_cnt[blk][bap] * ff_ac3_bap_bits[bap]; 161 } 162 return bits; 163} 164 165static void ac3_extract_exponents_c(uint8_t *exp, int32_t *coef, int nb_coefs) 166{ 167 int i; 168 169 for (i = 0; i < nb_coefs; i++) { 170 int v = abs(coef[i]); 171 exp[i] = v ? 23 - av_log2(v) : 24; 172 } 173} 174 175static void ac3_sum_square_butterfly_int32_c(int64_t sum[4], 176 const int32_t *coef0, 177 const int32_t *coef1, 178 int len) 179{ 180 int i; 181 182 sum[0] = sum[1] = sum[2] = sum[3] = 0; 183 184 for (i = 0; i < len; i++) { 185 int lt = coef0[i]; 186 int rt = coef1[i]; 187 int md = lt + rt; 188 int sd = lt - rt; 189 MAC64(sum[0], lt, lt); 190 MAC64(sum[1], rt, rt); 191 MAC64(sum[2], md, md); 192 MAC64(sum[3], sd, sd); 193 } 194} 195 196static void ac3_sum_square_butterfly_float_c(float sum[4], 197 const float *coef0, 198 const float *coef1, 199 int len) 200{ 201 int i; 202 203 sum[0] = sum[1] = sum[2] = sum[3] = 0; 204 205 for (i = 0; i < len; i++) { 206 float lt = coef0[i]; 207 float rt = coef1[i]; 208 float md = lt + rt; 209 float sd = lt - rt; 210 sum[0] += lt * lt; 211 sum[1] += rt * rt; 212 sum[2] += md * md; 213 sum[3] += sd * sd; 214 } 215} 216 217static void ac3_downmix_c(float **samples, float (*matrix)[2], 218 int out_ch, int in_ch, int len) 219{ 220 int i, j; 221 float v0, v1; 222 if (out_ch == 2) { 223 for (i = 0; i < len; i++) { 224 v0 = v1 = 0.0f; 225 for (j = 0; j < in_ch; j++) { 226 v0 += samples[j][i] * matrix[j][0]; 227 v1 += samples[j][i] * matrix[j][1]; 228 } 229 samples[0][i] = v0; 230 samples[1][i] = v1; 231 } 232 } else if (out_ch == 1) { 233 for (i = 0; i < len; i++) { 234 v0 = 0.0f; 235 for (j = 0; j < in_ch; j++) 236 v0 += samples[j][i] * matrix[j][0]; 237 samples[0][i] = v0; 238 } 239 } 240} 241 242static void ac3_downmix_c_fixed(int32_t **samples, int16_t (*matrix)[2], 243 int out_ch, int in_ch, int len) 244{ 245 int i, j; 246 int64_t v0, v1; 247 if (out_ch == 2) { 248 for (i = 0; i < len; i++) { 249 v0 = v1 = 0; 250 for (j = 0; j < in_ch; j++) { 251 v0 += (int64_t)samples[j][i] * matrix[j][0]; 252 v1 += (int64_t)samples[j][i] * matrix[j][1]; 253 } 254 samples[0][i] = (v0+2048)>>12; 255 samples[1][i] = (v1+2048)>>12; 256 } 257 } else if (out_ch == 1) { 258 for (i = 0; i < len; i++) { 259 v0 = 0; 260 for (j = 0; j < in_ch; j++) 261 v0 += (int64_t)samples[j][i] * matrix[j][0]; 262 samples[0][i] = (v0+2048)>>12; 263 } 264 } 265} 266 267static void apply_window_int16_c(int16_t *output, const int16_t *input, 268 const int16_t *window, unsigned int len) 269{ 270 int i; 271 int len2 = len >> 1; 272 273 for (i = 0; i < len2; i++) { 274 int16_t w = window[i]; 275 output[i] = (MUL16(input[i], w) + (1 << 14)) >> 15; 276 output[len-i-1] = (MUL16(input[len-i-1], w) + (1 << 14)) >> 15; 277 } 278} 279 280av_cold void ff_ac3dsp_init(AC3DSPContext *c, int bit_exact) 281{ 282 c->ac3_exponent_min = ac3_exponent_min_c; 283 c->ac3_max_msb_abs_int16 = ac3_max_msb_abs_int16_c; 284 c->ac3_lshift_int16 = ac3_lshift_int16_c; 285 c->ac3_rshift_int32 = ac3_rshift_int32_c; 286 c->float_to_fixed24 = float_to_fixed24_c; 287 c->bit_alloc_calc_bap = ac3_bit_alloc_calc_bap_c; 288 c->update_bap_counts = ac3_update_bap_counts_c; 289 c->compute_mantissa_size = ac3_compute_mantissa_size_c; 290 c->extract_exponents = ac3_extract_exponents_c; 291 c->sum_square_butterfly_int32 = ac3_sum_square_butterfly_int32_c; 292 c->sum_square_butterfly_float = ac3_sum_square_butterfly_float_c; 293 c->downmix = ac3_downmix_c; 294 c->downmix_fixed = ac3_downmix_c_fixed; 295 c->apply_window_int16 = apply_window_int16_c; 296 297 if (ARCH_ARM) 298 ff_ac3dsp_init_arm(c, bit_exact); 299 if (ARCH_X86) 300 ff_ac3dsp_init_x86(c, bit_exact); 301 if (ARCH_MIPS) 302 ff_ac3dsp_init_mips(c, bit_exact); 303} 304