58 lines
1.3 KiB
C
58 lines
1.3 KiB
C
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#include "./lowpass.h"
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#include <assert.h>
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#include <stdatomic.h>
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#include <stddef.h>
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#include "util/math/algorithm.h"
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#include "./effect.h"
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#include "./format.h"
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static void jukebox_lowpass_affect_(
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jukebox_effect_t* effect, const jukebox_effect_pcm_t* pcm) {
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assert(effect != NULL);
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assert(pcm != NULL);
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jukebox_lowpass_t* lp = (typeof(lp)) effect;
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const size_t ch = lp->format.channels;
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const float f = atomic_load(&lp->factor) * JUKEBOX_LOWPASS_FACTOR_UNIT;
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assert(ch <= JUKEBOX_LOWPASS_SUPPORT_MAX_CHANNELS);
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const size_t pcmlen = pcm->frames * ch;
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for (size_t i = 0; i < pcmlen; ++i) {
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const float p = (ch+1 <= i? pcm->ptr[i-1-ch]: lp->prev[i]);
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pcm->ptr[i] = (1.0f-f)*pcm->ptr[i] + f*p;
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}
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if (pcmlen < ch) return;
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for (size_t i = 0; i < ch; ++i) {
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lp->prev[i] = pcm->ptr[pcmlen-ch+i];
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}
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}
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void jukebox_lowpass_initialize(
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jukebox_lowpass_t* lowpass, const jukebox_format_t* format, float factor) {
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assert(lowpass != NULL);
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assert(jukebox_format_valid(format));
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assert(MATH_FLOAT_VALID(factor));
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*lowpass = (typeof(*lowpass)) {
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.super = {
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.vtable = {
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.affect = jukebox_lowpass_affect_,
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},
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},
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.format = *format,
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.factor = factor*10000,
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.prev = {0},
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};
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}
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void jukebox_lowpass_deinitialize(jukebox_lowpass_t* lowpass) {
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assert(lowpass != NULL);
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}
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