Ajout octaver
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thomas committed
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@@ -2,6 +2,7 @@
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#define AUDIO_EFFECTS_H
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#include <stdbool.h>
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#include "fx_octaver.h"
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#include "fx_equalizer.h"
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#include "fx_overdrive.h"
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#include "fx_saturation.h"
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@@ -14,10 +15,11 @@ extern "C" {
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/* Structure regroupant les parametres de tous les effets. Modifiable directement
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* (ex: depuis l'IHM) via AudioEffects_GetParams(). L'ordre de traitement fixe est :
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* egaliseur -> overdrive -> saturation -> echo -> reverberation. */
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* octaveur -> egaliseur -> overdrive -> saturation -> echo -> reverberation. */
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typedef struct
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{
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bool audio_on_off;
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FxOctaverParams octaver;
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FxEqualizerParams equalizer;
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FxOverdriveParams overdrive;
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FxSaturationParams saturation;
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@@ -0,0 +1,44 @@
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#ifndef FX_OCTAVER_H
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#define FX_OCTAVER_H
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#include <stdbool.h>
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define FX_OCTAVER_BUFFER_SIZE 2048U /* buffer circulaire (puissance de 2) */
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#define FX_OCTAVER_GRAIN_SIZE 1024U /* taille de grain, en echantillons (~21ms a 48kHz) */
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#define FX_OCTAVER_NUM_VOICES 4U /* -2oct, -1oct, +1oct, +2oct (la voie seche est geree a part) */
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typedef struct
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{
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bool enabled;
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float level_down2; /* niveau voix -2 octaves, 0.0 a 1.0 */
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float level_down1; /* niveau voix -1 octave, 0.0 a 1.0 */
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float level_dry; /* niveau voix originale, 0.0 a 1.0 */
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float level_up1; /* niveau voix +1 octave, 0.0 a 1.0 */
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float level_up2; /* niveau voix +2 octaves, 0.0 a 1.0 */
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} FxOctaverParams;
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typedef struct
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{
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float delay[2]; /* decalage courant (en echantillons) des deux grains en fondu croise */
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} FxOctaverVoiceState;
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typedef struct
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{
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float buffer[FX_OCTAVER_BUFFER_SIZE];
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uint32_t write_idx;
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FxOctaverVoiceState voices[FX_OCTAVER_NUM_VOICES];
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} FxOctaverState;
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void FxOctaver_Init(FxOctaverState *state, FxOctaverParams *params);
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float FxOctaver_Process(FxOctaverState *state, const FxOctaverParams *params, float input);
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#ifdef __cplusplus
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}
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#endif
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#endif /* FX_OCTAVER_H */
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@@ -2,6 +2,7 @@
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static AudioEffectsParams g_params;
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static FxOctaverState g_octaverState;
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static FxEqualizerState g_eqState;
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static FxOverdriveState g_overdriveState;
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static FxSaturationState g_saturationState;
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@@ -11,6 +12,7 @@ static FxReverbState g_reverbState;
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void AudioEffects_Init(void)
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{
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g_params.audio_on_off = false;
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FxOctaver_Init(&g_octaverState, &g_params.octaver);
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FxEqualizer_Init(&g_eqState, &g_params.equalizer);
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FxOverdrive_Init(&g_overdriveState, &g_params.overdrive);
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FxSaturation_Init(&g_saturationState, &g_params.saturation);
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@@ -21,6 +23,7 @@ void AudioEffects_Init(void)
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float AudioEffects_Process(float input)
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{
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float sample = input;
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sample = FxOctaver_Process(&g_octaverState, &g_params.octaver, sample);
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sample = FxEqualizer_Process(&g_eqState, &g_params.equalizer, sample);
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sample = FxOverdrive_Process(&g_overdriveState, &g_params.overdrive, sample);
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sample = FxSaturation_Process(&g_saturationState, &g_params.saturation, sample);
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@@ -0,0 +1,141 @@
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#include "fx_octaver.h"
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#include <math.h>
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#define FX_OCTAVER_BUFFER_MASK (FX_OCTAVER_BUFFER_SIZE - 1U)
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#define FX_OCTAVER_ENV_TABLE_SIZE 256U
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/* Rapport de vitesse de lecture pour chaque voix : lire le buffer plus vite que
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* l'ecriture multiplie la frequence (octave au-dessus), plus lentement la divise
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* (octave en-dessous). */
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static const float fx_octaver_ratios[FX_OCTAVER_NUM_VOICES] =
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{
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0.25f, /* -2 octaves */
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0.5f, /* -1 octave */
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2.0f, /* +1 octave */
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4.0f /* +2 octaves */
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};
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/* Fenetre de Hann tabulee (evite un cosf() par grain et par echantillon). */
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static float fx_octaver_env_table[FX_OCTAVER_ENV_TABLE_SIZE + 1U];
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static bool fx_octaver_env_table_ready = false;
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static void FxOctaver_BuildEnvTable(void)
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{
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if (fx_octaver_env_table_ready)
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{
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return;
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}
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for (uint32_t i = 0; i <= FX_OCTAVER_ENV_TABLE_SIZE; i++)
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{
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float phase = (float)i / (float)FX_OCTAVER_ENV_TABLE_SIZE;
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fx_octaver_env_table[i] = 0.5f - 0.5f * cosf(2.0f * (float)M_PI * phase);
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}
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fx_octaver_env_table_ready = true;
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}
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static inline float FxOctaver_EnvLookup(float phase)
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{
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float pos = phase * (float)FX_OCTAVER_ENV_TABLE_SIZE;
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uint32_t i0 = (uint32_t)pos;
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if (i0 >= FX_OCTAVER_ENV_TABLE_SIZE)
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{
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i0 = FX_OCTAVER_ENV_TABLE_SIZE - 1U;
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}
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float frac = pos - (float)i0;
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return fx_octaver_env_table[i0] * (1.0f - frac) + fx_octaver_env_table[i0 + 1U] * frac;
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}
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static inline float FxOctaver_ReadInterpolated(const float *buffer, uint32_t write_idx, float delay)
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{
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float read_pos = (float)write_idx - delay;
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while (read_pos < 0.0f)
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{
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read_pos += (float)FX_OCTAVER_BUFFER_SIZE;
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}
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uint32_t i0 = (uint32_t)read_pos & FX_OCTAVER_BUFFER_MASK;
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uint32_t i1 = (i0 + 1U) & FX_OCTAVER_BUFFER_MASK;
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float frac = read_pos - (float)(uint32_t)read_pos;
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return buffer[i0] * (1.0f - frac) + buffer[i1] * frac;
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}
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/* Lecteur de grains a deux pointeurs en fondu croise : chaque pointeur avance
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* (ou recule) dans le buffer a une vitesse "ratio" differente de celle de
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* l'ecriture, ce qui change la hauteur percue. Les deux grains sont toujours
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* en opposition de phase exacte (decales d'un demi-grain a l'origine, et le
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* meme increment est applique aux deux avant chaque repli) : la fenetre de
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* Hann du second grain vaut donc toujours 1 moins celle du premier, ce qui
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* garantit un niveau de sortie constant pendant le fondu et evite un second
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* calcul de fenetre. */
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static float FxOctaver_ProcessVoice(FxOctaverVoiceState *vs, const float *buffer, uint32_t write_idx, float ratio)
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{
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float step = 1.0f - ratio;
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for (uint32_t g = 0; g < 2U; g++)
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{
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vs->delay[g] += step;
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if (vs->delay[g] >= (float)FX_OCTAVER_GRAIN_SIZE)
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{
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vs->delay[g] -= (float)FX_OCTAVER_GRAIN_SIZE;
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}
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else if (vs->delay[g] < 0.0f)
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{
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vs->delay[g] += (float)FX_OCTAVER_GRAIN_SIZE;
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}
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}
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float phase0 = vs->delay[0] / (float)FX_OCTAVER_GRAIN_SIZE;
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float env0 = FxOctaver_EnvLookup(phase0);
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float env1 = 1.0f - env0;
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float sample0 = FxOctaver_ReadInterpolated(buffer, write_idx, vs->delay[0]);
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float sample1 = FxOctaver_ReadInterpolated(buffer, write_idx, vs->delay[1]);
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return env0 * sample0 + env1 * sample1;
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}
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void FxOctaver_Init(FxOctaverState *state, FxOctaverParams *params)
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{
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params->enabled = false;
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params->level_down2 = 0.0f;
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params->level_down1 = 0.0f;
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params->level_dry = 1.0f;
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params->level_up1 = 0.0f;
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params->level_up2 = 0.0f;
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for (uint32_t i = 0; i < FX_OCTAVER_BUFFER_SIZE; i++)
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{
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state->buffer[i] = 0.0f;
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}
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state->write_idx = 0U;
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for (uint32_t v = 0; v < FX_OCTAVER_NUM_VOICES; v++)
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{
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state->voices[v].delay[0] = 0.0f;
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state->voices[v].delay[1] = (float)FX_OCTAVER_GRAIN_SIZE * 0.5f;
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}
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FxOctaver_BuildEnvTable();
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}
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float FxOctaver_Process(FxOctaverState *state, const FxOctaverParams *params, float input)
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{
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if (!params->enabled)
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{
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return input;
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}
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state->buffer[state->write_idx & FX_OCTAVER_BUFFER_MASK] = input;
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float down2 = FxOctaver_ProcessVoice(&state->voices[0], state->buffer, state->write_idx, fx_octaver_ratios[0]);
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float down1 = FxOctaver_ProcessVoice(&state->voices[1], state->buffer, state->write_idx, fx_octaver_ratios[1]);
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float up1 = FxOctaver_ProcessVoice(&state->voices[2], state->buffer, state->write_idx, fx_octaver_ratios[2]);
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float up2 = FxOctaver_ProcessVoice(&state->voices[3], state->buffer, state->write_idx, fx_octaver_ratios[3]);
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state->write_idx++;
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return input * params->level_dry
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+ down2 * params->level_down2
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+ down1 * params->level_down1
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+ up1 * params->level_up1
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+ up2 * params->level_up2;
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}
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