| 1 | /* libFLAC - Free Lossless Audio Codec library |
| 2 | * Copyright (C) 2006-2009 Josh Coalson |
| 3 | * Copyright (C) 2011-2016 Xiph.Org Foundation |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * |
| 9 | * - Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * |
| 12 | * - Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * |
| 16 | * - Neither the name of the Xiph.org Foundation nor the names of its |
| 17 | * contributors may be used to endorse or promote products derived from |
| 18 | * this software without specific prior written permission. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 22 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 23 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
| 24 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 25 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 26 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 27 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 28 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 29 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 30 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 31 | */ |
| 32 | |
| 33 | #ifdef HAVE_CONFIG_H |
| 34 | # include <config.h> |
| 35 | #endif |
| 36 | |
| 37 | #include <math.h> |
| 38 | #include "share/compat.h" |
| 39 | #include "FLAC/assert.h" |
| 40 | #include "FLAC/format.h" |
| 41 | #include "private/window.h" |
| 42 | |
| 43 | #ifndef FLAC__INTEGER_ONLY_LIBRARY |
| 44 | |
| 45 | |
| 46 | void FLAC__window_bartlett(FLAC__real *window, const FLAC__int32 L) |
| 47 | { |
| 48 | const FLAC__int32 N = L - 1; |
| 49 | FLAC__int32 n; |
| 50 | |
| 51 | if (L & 1) { |
| 52 | for (n = 0; n <= N/2; n++) |
| 53 | window[n] = 2.0f * n / (float)N; |
| 54 | for (; n <= N; n++) |
| 55 | window[n] = 2.0f - 2.0f * n / (float)N; |
| 56 | } |
| 57 | else { |
| 58 | for (n = 0; n <= L/2-1; n++) |
| 59 | window[n] = 2.0f * n / (float)N; |
| 60 | for (; n <= N; n++) |
| 61 | window[n] = 2.0f - 2.0f * n / (float)N; |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | void FLAC__window_bartlett_hann(FLAC__real *window, const FLAC__int32 L) |
| 66 | { |
| 67 | const FLAC__int32 N = L - 1; |
| 68 | FLAC__int32 n; |
| 69 | |
| 70 | for (n = 0; n < L; n++) |
| 71 | window[n] = (FLAC__real)(0.62f - 0.48f * fabs((float)n/(float)N-0.5f) - 0.38f * cos(2.0f * M_PI * ((float)n/(float)N))); |
| 72 | } |
| 73 | |
| 74 | void FLAC__window_blackman(FLAC__real *window, const FLAC__int32 L) |
| 75 | { |
| 76 | const FLAC__int32 N = L - 1; |
| 77 | FLAC__int32 n; |
| 78 | |
| 79 | for (n = 0; n < L; n++) |
| 80 | window[n] = (FLAC__real)(0.42f - 0.5f * cos(2.0f * M_PI * n / N) + 0.08f * cos(4.0f * M_PI * n / N)); |
| 81 | } |
| 82 | |
| 83 | /* 4-term -92dB side-lobe */ |
| 84 | void FLAC__window_blackman_harris_4term_92db_sidelobe(FLAC__real *window, const FLAC__int32 L) |
| 85 | { |
| 86 | const FLAC__int32 N = L - 1; |
| 87 | FLAC__int32 n; |
| 88 | |
| 89 | for (n = 0; n <= N; n++) |
| 90 | window[n] = (FLAC__real)(0.35875f - 0.48829f * cos(2.0f * M_PI * n / N) + 0.14128f * cos(4.0f * M_PI * n / N) - 0.01168f * cos(6.0f * M_PI * n / N)); |
| 91 | } |
| 92 | |
| 93 | void FLAC__window_connes(FLAC__real *window, const FLAC__int32 L) |
| 94 | { |
| 95 | const FLAC__int32 N = L - 1; |
| 96 | const double N2 = (double)N / 2.; |
| 97 | FLAC__int32 n; |
| 98 | |
| 99 | for (n = 0; n <= N; n++) { |
| 100 | double k = ((double)n - N2) / N2; |
| 101 | k = 1.0f - k * k; |
| 102 | window[n] = (FLAC__real)(k * k); |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | void FLAC__window_flattop(FLAC__real *window, const FLAC__int32 L) |
| 107 | { |
| 108 | const FLAC__int32 N = L - 1; |
| 109 | FLAC__int32 n; |
| 110 | |
| 111 | for (n = 0; n < L; n++) |
| 112 | window[n] = (FLAC__real)(1.0f - 1.93f * cos(2.0f * M_PI * n / N) + 1.29f * cos(4.0f * M_PI * n / N) - 0.388f * cos(6.0f * M_PI * n / N) + 0.0322f * cos(8.0f * M_PI * n / N)); |
| 113 | } |
| 114 | |
| 115 | void FLAC__window_gauss(FLAC__real *window, const FLAC__int32 L, const FLAC__real stddev) |
| 116 | { |
| 117 | const FLAC__int32 N = L - 1; |
| 118 | const double N2 = (double)N / 2.; |
| 119 | FLAC__int32 n; |
| 120 | |
| 121 | for (n = 0; n <= N; n++) { |
| 122 | const double k = ((double)n - N2) / (stddev * N2); |
| 123 | window[n] = (FLAC__real)exp(-0.5f * k * k); |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | void FLAC__window_hamming(FLAC__real *window, const FLAC__int32 L) |
| 128 | { |
| 129 | const FLAC__int32 N = L - 1; |
| 130 | FLAC__int32 n; |
| 131 | |
| 132 | for (n = 0; n < L; n++) |
| 133 | window[n] = (FLAC__real)(0.54f - 0.46f * cos(2.0f * M_PI * n / N)); |
| 134 | } |
| 135 | |
| 136 | void FLAC__window_hann(FLAC__real *window, const FLAC__int32 L) |
| 137 | { |
| 138 | const FLAC__int32 N = L - 1; |
| 139 | FLAC__int32 n; |
| 140 | |
| 141 | for (n = 0; n < L; n++) |
| 142 | window[n] = (FLAC__real)(0.5f - 0.5f * cos(2.0f * M_PI * n / N)); |
| 143 | } |
| 144 | |
| 145 | void FLAC__window_kaiser_bessel(FLAC__real *window, const FLAC__int32 L) |
| 146 | { |
| 147 | const FLAC__int32 N = L - 1; |
| 148 | FLAC__int32 n; |
| 149 | |
| 150 | for (n = 0; n < L; n++) |
| 151 | window[n] = (FLAC__real)(0.402f - 0.498f * cos(2.0f * M_PI * n / N) + 0.098f * cos(4.0f * M_PI * n / N) - 0.001f * cos(6.0f * M_PI * n / N)); |
| 152 | } |
| 153 | |
| 154 | void FLAC__window_nuttall(FLAC__real *window, const FLAC__int32 L) |
| 155 | { |
| 156 | const FLAC__int32 N = L - 1; |
| 157 | FLAC__int32 n; |
| 158 | |
| 159 | for (n = 0; n < L; n++) |
| 160 | window[n] = (FLAC__real)(0.3635819f - 0.4891775f*cos(2.0f*M_PI*n/N) + 0.1365995f*cos(4.0f*M_PI*n/N) - 0.0106411f*cos(6.0f*M_PI*n/N)); |
| 161 | } |
| 162 | |
| 163 | void FLAC__window_rectangle(FLAC__real *window, const FLAC__int32 L) |
| 164 | { |
| 165 | FLAC__int32 n; |
| 166 | |
| 167 | for (n = 0; n < L; n++) |
| 168 | window[n] = 1.0f; |
| 169 | } |
| 170 | |
| 171 | void FLAC__window_triangle(FLAC__real *window, const FLAC__int32 L) |
| 172 | { |
| 173 | FLAC__int32 n; |
| 174 | |
| 175 | if (L & 1) { |
| 176 | for (n = 1; n <= (L+1)/2; n++) |
| 177 | window[n-1] = 2.0f * n / ((float)L + 1.0f); |
| 178 | for (; n <= L; n++) |
| 179 | window[n-1] = (float)(2 * (L - n + 1)) / ((float)L + 1.0f); |
| 180 | } |
| 181 | else { |
| 182 | for (n = 1; n <= L/2; n++) |
| 183 | window[n-1] = 2.0f * n / ((float)L + 1.0f); |
| 184 | for (; n <= L; n++) |
| 185 | window[n-1] = (float)(2 * (L - n + 1)) / ((float)L + 1.0f); |
| 186 | } |
| 187 | } |
| 188 | |
| 189 | void FLAC__window_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p) |
| 190 | { |
| 191 | if (p <= 0.0) |
| 192 | FLAC__window_rectangle(window, L); |
| 193 | else if (p >= 1.0) |
| 194 | FLAC__window_hann(window, L); |
| 195 | else { |
| 196 | const FLAC__int32 Np = (FLAC__int32)(p / 2.0f * L) - 1; |
| 197 | FLAC__int32 n; |
| 198 | /* start with rectangle... */ |
| 199 | FLAC__window_rectangle(window, L); |
| 200 | /* ...replace ends with hann */ |
| 201 | if (Np > 0) { |
| 202 | for (n = 0; n <= Np; n++) { |
| 203 | window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * n / Np)); |
| 204 | window[L-Np-1+n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * (n+Np) / Np)); |
| 205 | } |
| 206 | } |
| 207 | } |
| 208 | } |
| 209 | |
| 210 | void FLAC__window_partial_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p, const FLAC__real start, const FLAC__real end) |
| 211 | { |
| 212 | const FLAC__int32 start_n = (FLAC__int32)(start * L); |
| 213 | const FLAC__int32 end_n = (FLAC__int32)(end * L); |
| 214 | const FLAC__int32 N = end_n - start_n; |
| 215 | FLAC__int32 Np, n, i; |
| 216 | |
| 217 | if (p <= 0.0f) |
| 218 | FLAC__window_partial_tukey(window, L, 0.05f, start, end); |
| 219 | else if (p >= 1.0f) |
| 220 | FLAC__window_partial_tukey(window, L, 0.95f, start, end); |
| 221 | else { |
| 222 | |
| 223 | Np = (FLAC__int32)(p / 2.0f * N); |
| 224 | |
| 225 | for (n = 0; n < start_n && n < L; n++) |
| 226 | window[n] = 0.0f; |
| 227 | for (i = 1; n < (start_n+Np) && n < L; n++, i++) |
| 228 | window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Np)); |
| 229 | for (; n < (end_n-Np) && n < L; n++) |
| 230 | window[n] = 1.0f; |
| 231 | for (i = Np; n < end_n && n < L; n++, i--) |
| 232 | window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Np)); |
| 233 | for (; n < L; n++) |
| 234 | window[n] = 0.0f; |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | void FLAC__window_punchout_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p, const FLAC__real start, const FLAC__real end) |
| 239 | { |
| 240 | const FLAC__int32 start_n = (FLAC__int32)(start * L); |
| 241 | const FLAC__int32 end_n = (FLAC__int32)(end * L); |
| 242 | FLAC__int32 Ns, Ne, n, i; |
| 243 | |
| 244 | if (p <= 0.0f) |
| 245 | FLAC__window_punchout_tukey(window, L, 0.05f, start, end); |
| 246 | else if (p >= 1.0f) |
| 247 | FLAC__window_punchout_tukey(window, L, 0.95f, start, end); |
| 248 | else { |
| 249 | |
| 250 | Ns = (FLAC__int32)(p / 2.0f * start_n); |
| 251 | Ne = (FLAC__int32)(p / 2.0f * (L - end_n)); |
| 252 | |
| 253 | for (n = 0, i = 1; n < Ns && n < L; n++, i++) |
| 254 | window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ns)); |
| 255 | for (; n < start_n-Ns && n < L; n++) |
| 256 | window[n] = 1.0f; |
| 257 | for (i = Ns; n < start_n && n < L; n++, i--) |
| 258 | window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ns)); |
| 259 | for (; n < end_n && n < L; n++) |
| 260 | window[n] = 0.0f; |
| 261 | for (i = 1; n < end_n+Ne && n < L; n++, i++) |
| 262 | window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ne)); |
| 263 | for (; n < L - (Ne) && n < L; n++) |
| 264 | window[n] = 1.0f; |
| 265 | for (i = Ne; n < L; n++, i--) |
| 266 | window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ne)); |
| 267 | } |
| 268 | } |
| 269 | |
| 270 | void FLAC__window_welch(FLAC__real *window, const FLAC__int32 L) |
| 271 | { |
| 272 | const FLAC__int32 N = L - 1; |
| 273 | const double N2 = (double)N / 2.; |
| 274 | FLAC__int32 n; |
| 275 | |
| 276 | for (n = 0; n <= N; n++) { |
| 277 | const double k = ((double)n - N2) / N2; |
| 278 | window[n] = (FLAC__real)(1.0f - k * k); |
| 279 | } |
| 280 | } |
| 281 | |
| 282 | #endif /* !defined FLAC__INTEGER_ONLY_LIBRARY */ |