diff options
Diffstat (limited to 'src/libFLAC/window.c')
| -rw-r--r-- | src/libFLAC/window.c | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/src/libFLAC/window.c b/src/libFLAC/window.c new file mode 100644 index 0000000..69d5464 --- /dev/null +++ b/src/libFLAC/window.c @@ -0,0 +1,308 @@ +/* libFLAC - Free Lossless Audio Codec library + * Copyright (C) 2006-2009 Josh Coalson + * Copyright (C) 2011-2023 Xiph.Org Foundation + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * - Neither the name of the Xiph.org Foundation nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <math.h> +#include "share/compat.h" +#include "FLAC/assert.h" +#include "FLAC/format.h" +#include "private/window.h" + +#ifndef FLAC__INTEGER_ONLY_LIBRARY + +#if defined(_MSC_VER) +// silence 25 MSVC warnings 'conversion from 'double' to 'float', possible loss of data' +#pragma warning ( disable : 4244 ) +#endif + +void FLAC__window_bartlett(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + if (L & 1) { + for (n = 0; n <= N/2; n++) + window[n] = 2.0f * n / (float)N; + for (; n <= N; n++) + window[n] = 2.0f - 2.0f * n / (float)N; + } + else { + for (n = 0; n <= L/2-1; n++) + window[n] = 2.0f * n / (float)N; + for (; n <= N; n++) + window[n] = 2.0f - 2.0f * n / (float)N; + } +} + +void FLAC__window_bartlett_hann(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + for (n = 0; n < L; n++) + window[n] = (FLAC__real)(0.62f - 0.48f * fabsf((float)n/(float)N-0.5f) - 0.38f * cosf(2.0f * M_PI * ((float)n/(float)N))); +} + +void FLAC__window_blackman(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + for (n = 0; n < L; n++) + window[n] = (FLAC__real)(0.42f - 0.5f * cosf(2.0f * M_PI * n / N) + 0.08f * cosf(4.0f * M_PI * n / N)); +} + +/* 4-term -92dB side-lobe */ +void FLAC__window_blackman_harris_4term_92db_sidelobe(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + for (n = 0; n <= N; n++) + window[n] = (FLAC__real)(0.35875f - 0.48829f * cosf(2.0f * M_PI * n / N) + 0.14128f * cosf(4.0f * M_PI * n / N) - 0.01168f * cosf(6.0f * M_PI * n / N)); +} + +void FLAC__window_connes(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + const double N2 = (double)N / 2.; + FLAC__int32 n; + + for (n = 0; n <= N; n++) { + double k = ((double)n - N2) / N2; + k = 1.0f - k * k; + window[n] = (FLAC__real)(k * k); + } +} + +void FLAC__window_flattop(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + for (n = 0; n < L; n++) + window[n] = (FLAC__real)(0.21557895f - 0.41663158f * cosf(2.0f * M_PI * n / N) + 0.277263158f * cosf(4.0f * M_PI * n / N) - 0.083578947f * cosf(6.0f * M_PI * n / N) + 0.006947368f * cosf(8.0f * M_PI * n / N)); +} + +void FLAC__window_gauss(FLAC__real *window, const FLAC__int32 L, const FLAC__real stddev) +{ + const FLAC__int32 N = L - 1; + const double N2 = (double)N / 2.; + FLAC__int32 n; + + if(!(stddev > 0.0f && stddev <= 0.5f)) + /* stddev is not between 0 and 0.5, might be NaN. + * Default to 0.5 */ + FLAC__window_gauss(window, L, 0.25f); + else { + for (n = 0; n <= N; n++) { + const double k = ((double)n - N2) / (stddev * N2); + window[n] = (FLAC__real)exp(-0.5f * k * k); + } + } +} + +void FLAC__window_hamming(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + for (n = 0; n < L; n++) + window[n] = (FLAC__real)(0.54f - 0.46f * cosf(2.0f * M_PI * n / N)); +} + +void FLAC__window_hann(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + for (n = 0; n < L; n++) + window[n] = (FLAC__real)(0.5f - 0.5f * cosf(2.0f * M_PI * n / N)); +} + +void FLAC__window_kaiser_bessel(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + for (n = 0; n < L; n++) + window[n] = (FLAC__real)(0.402f - 0.498f * cosf(2.0f * M_PI * n / N) + 0.098f * cosf(4.0f * M_PI * n / N) - 0.001f * cosf(6.0f * M_PI * n / N)); +} + +void FLAC__window_nuttall(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + FLAC__int32 n; + + for (n = 0; n < L; n++) + window[n] = (FLAC__real)(0.3635819f - 0.4891775f*cosf(2.0f*M_PI*n/N) + 0.1365995f*cosf(4.0f*M_PI*n/N) - 0.0106411f*cosf(6.0f*M_PI*n/N)); +} + +void FLAC__window_rectangle(FLAC__real *window, const FLAC__int32 L) +{ + FLAC__int32 n; + + for (n = 0; n < L; n++) + window[n] = 1.0f; +} + +void FLAC__window_triangle(FLAC__real *window, const FLAC__int32 L) +{ + FLAC__int32 n; + + if (L & 1) { + for (n = 1; n <= (L+1)/2; n++) + window[n-1] = 2.0f * n / ((float)L + 1.0f); + for (; n <= L; n++) + window[n-1] = (float)(2 * (L - n + 1)) / ((float)L + 1.0f); + } + else { + for (n = 1; n <= L/2; n++) + window[n-1] = 2.0f * n / ((float)L + 1.0f); + for (; n <= L; n++) + window[n-1] = (float)(2 * (L - n + 1)) / ((float)L + 1.0f); + } +} + +void FLAC__window_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p) +{ + if (p <= 0.0) + FLAC__window_rectangle(window, L); + else if (p >= 1.0) + FLAC__window_hann(window, L); + else if (!(p > 0.0f && p < 1.0f)) + /* p is not between 0 and 1, probably NaN. + * Default to 0.5 */ + FLAC__window_tukey(window, L, 0.5f); + else { + const FLAC__int32 Np = (FLAC__int32)(p / 2.0f * L) - 1; + FLAC__int32 n; + /* start with rectangle... */ + FLAC__window_rectangle(window, L); + /* ...replace ends with hann */ + if (Np > 0) { + for (n = 0; n <= Np; n++) { + window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * n / Np)); + window[L-Np-1+n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * (n+Np) / Np)); + } + } + } +} + +void FLAC__window_partial_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p, const FLAC__real start, const FLAC__real end) +{ + const FLAC__int32 start_n = (FLAC__int32)(start * L); + const FLAC__int32 end_n = (FLAC__int32)(end * L); + const FLAC__int32 N = end_n - start_n; + FLAC__int32 Np, n, i; + + if (p <= 0.0f) + FLAC__window_partial_tukey(window, L, 0.05f, start, end); + else if (p >= 1.0f) + FLAC__window_partial_tukey(window, L, 0.95f, start, end); + else if (!(p > 0.0f && p < 1.0f)) + /* p is not between 0 and 1, probably NaN. + * Default to 0.5 */ + FLAC__window_partial_tukey(window, L, 0.5f, start, end); + else { + + Np = (FLAC__int32)(p / 2.0f * N); + + for (n = 0; n < start_n && n < L; n++) + window[n] = 0.0f; + for (i = 1; n < (start_n+Np) && n < L; n++, i++) + window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Np)); + for (; n < (end_n-Np) && n < L; n++) + window[n] = 1.0f; + for (i = Np; n < end_n && n < L; n++, i--) + window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Np)); + for (; n < L; n++) + window[n] = 0.0f; + } +} + +void FLAC__window_punchout_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p, const FLAC__real start, const FLAC__real end) +{ + const FLAC__int32 start_n = (FLAC__int32)(start * L); + const FLAC__int32 end_n = (FLAC__int32)(end * L); + FLAC__int32 Ns, Ne, n, i; + + if (p <= 0.0f) + FLAC__window_punchout_tukey(window, L, 0.05f, start, end); + else if (p >= 1.0f) + FLAC__window_punchout_tukey(window, L, 0.95f, start, end); + else if (!(p > 0.0f && p < 1.0f)) + /* p is not between 0 and 1, probably NaN. + * Default to 0.5 */ + FLAC__window_punchout_tukey(window, L, 0.5f, start, end); + else { + + Ns = (FLAC__int32)(p / 2.0f * start_n); + Ne = (FLAC__int32)(p / 2.0f * (L - end_n)); + + for (n = 0, i = 1; n < Ns && n < L; n++, i++) + window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Ns)); + for (; n < start_n-Ns && n < L; n++) + window[n] = 1.0f; + for (i = Ns; n < start_n && n < L; n++, i--) + window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Ns)); + for (; n < end_n && n < L; n++) + window[n] = 0.0f; + for (i = 1; n < end_n+Ne && n < L; n++, i++) + window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Ne)); + for (; n < L - (Ne) && n < L; n++) + window[n] = 1.0f; + for (i = Ne; n < L; n++, i--) + window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Ne)); + } +} + +void FLAC__window_welch(FLAC__real *window, const FLAC__int32 L) +{ + const FLAC__int32 N = L - 1; + const double N2 = (double)N / 2.; + FLAC__int32 n; + + for (n = 0; n <= N; n++) { + const double k = ((double)n - N2) / N2; + window[n] = (FLAC__real)(1.0f - k * k); + } +} + +#if defined(_MSC_VER) +#pragma warning ( default : 4244 ) +#endif + +#endif /* !defined FLAC__INTEGER_ONLY_LIBRARY */ |