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https://gitlab.freedesktop.org/pipewire/pipewire.git
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68 lines
2.1 KiB
C
68 lines
2.1 KiB
C
/* Spa
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*
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* Copyright © 2022 Wim Taymans
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#include "dither-ops.h"
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/* 32 bit xorshift PRNG, see https://en.wikipedia.org/wiki/Xorshift */
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static inline uint32_t
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xorshift(uint32_t *state)
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{
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uint32_t x = *state;
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x ^= x << 13;
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x ^= x >> 17;
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x ^= x << 5;
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return (*state = x);
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}
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static inline void update_dither_c(struct dither *dt, uint32_t n_samples)
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{
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uint32_t n;
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for (n = 0; n < n_samples; n++)
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dt->dither[n] = ((int32_t)xorshift(&dt->random[0])) * dt->scale;
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}
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void dither_f32_c(struct dither *dt, void * SPA_RESTRICT dst[],
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const void * SPA_RESTRICT src[], uint32_t n_samples)
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{
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uint32_t i, n, m, chunk;
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const float **s = (const float**)src;
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float **d = (float**)dst;
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float *t = dt->dither;
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chunk = SPA_MIN(n_samples, dt->dither_size);
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update_dither_c(dt, chunk);
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for (n = 0; n < n_samples; n += chunk) {
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chunk = SPA_MIN(n_samples - n, dt->dither_size);
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for (i = 0; i < dt->n_channels; i++) {
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float *di = &d[i][n];
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const float *si = &s[i][n];
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for (m = 0; m < chunk; m++)
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di[m] = si[m] + t[m];
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}
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}
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}
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