This repository has been archived on 2022-05-21. You can view files and clone it, but cannot push or open issues or pull requests.
LEFTONE/util/jukebox/amp.c

84 lines
2.0 KiB
C
Raw Normal View History

#include "./amp.h"
#include <assert.h>
#include <stdatomic.h>
#include <stddef.h>
#include <stdint.h>
#include "util/math/algorithm.h"
#include "util/math/rational.h"
#include "./effect.h"
#include "./format.h"
/* FIXME: Whether this solution works fine,
depends on how long the operation is done. */
static void jukebox_amp_affect_(
jukebox_effect_t* effect, const jukebox_effect_pcm_t* pcm) {
assert(effect != NULL);
assert(pcm != NULL);
jukebox_amp_t* amp = (typeof(amp)) effect;
const uint64_t easedur = atomic_load(&amp->ease_duration);
const uint64_t elapsed = atomic_load(&amp->elapsed);
const float prev = atomic_load(&amp->prev_amount)/1000.0f;
const float next = atomic_load(&amp->next_amount)/1000.0f;
float* ptr = pcm->ptr;
for (int32_t i = 0; i < pcm->frames; ++i) {
float a = next;
if (elapsed < easedur) {
a = (prev-next) * (easedur-elapsed) / easedur + next;
}
for (int32_t j = 0; j < amp->format.channels; ++j) {
*(ptr++) *= a;
}
}
atomic_fetch_add(&amp->elapsed, pcm->frames);
}
void jukebox_amp_initialize(
jukebox_amp_t* amp, const jukebox_format_t* format) {
assert(amp != NULL);
assert(jukebox_format_valid(format));
*amp = (typeof(*amp)) {
.super = {
.vtable = {
.affect = jukebox_amp_affect_,
},
},
.format = *format,
};
}
void jukebox_amp_deinitialize(jukebox_amp_t* amp) {
assert(amp != NULL);
}
void jukebox_amp_change_volume(
jukebox_amp_t* amp, float amount, const rational_t* duration) {
assert(amp != NULL);
assert(MATH_FLOAT_VALID(amount));
assert(amount >= 0);
const float srate = amp->format.sample_rate;
atomic_store(&amp->ease_duration, 0);
atomic_store(&amp->elapsed, 0);
atomic_store(&amp->prev_amount, amp->next_amount);
rational_t dur = rational(1, 100);
if (rational_valid(duration)) rational_addeq(&dur, duration);
rational_normalize(&dur, srate);
atomic_store(&amp->next_amount, (uint16_t) (amount*1000));
atomic_store(&amp->ease_duration, dur.num);
}