From acdc543c8b3f2d11af2c8370ed905e2af6dad9dd Mon Sep 17 00:00:00 2001
From: ale <ale@incal.net>
Date: Sun, 10 Mar 2019 09:51:14 +0000
Subject: [PATCH] Initial support for timing/velocity humanization
With an algorithm pulled from drumgizmo.
---
Makefile.am | 3 +-
engine/drumkit.c | 1 +
engine/drumkit.h | 1 +
engine/humanize.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++
engine/humanize.h | 29 +++++++++++++++++
engine/sampler.c | 41 +++++++++++++++++++-----
engine/sampler.h | 8 ++++-
plugin/plugin.c | 4 ++-
8 files changed, 157 insertions(+), 11 deletions(-)
create mode 100644 engine/humanize.c
create mode 100644 engine/humanize.h
diff --git a/Makefile.am b/Makefile.am
index f951194..60d7d17 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -5,7 +5,8 @@ noinst_LTLIBRARIES = libengine.la
libengine_la_SOURCES = \
engine/exponential_tables.h \
engine/adsr.c engine/adsr.h \
- engine/voice.h engine/voice.c \
+ engine/voice.c engine/voice.h \
+ engine/humanize.c engine/humanize.h \
engine/drumkit.c engine/drumkit.h \
engine/sampler.c engine/sampler.h
libengine_la_LIBADD = $(SNDFILE_LIBS) $(SAMPLERATE_LIBS)
diff --git a/engine/drumkit.c b/engine/drumkit.c
index ca1d071..98678b6 100644
--- a/engine/drumkit.c
+++ b/engine/drumkit.c
@@ -386,6 +386,7 @@ static int parse_instruments(struct instrument **instruments,
for (i = 0; i < n; i++) {
instrument_set_defaults(&(*instruments)[i]);
+ (*instruments)[i].index = i;
if (!parse_instrument(&(*instruments)[i], nodes->nodeTab[i], xpathCtx, basedir, target_samplerate)) {
return 0;
}
diff --git a/engine/drumkit.h b/engine/drumkit.h
index b74d25a..b349f5a 100644
--- a/engine/drumkit.h
+++ b/engine/drumkit.h
@@ -16,6 +16,7 @@ struct layer {
};
struct instrument {
+ int index;
char *name;
int note;
float envelope_attack, envelope_decay,
diff --git a/engine/humanize.c b/engine/humanize.c
new file mode 100644
index 0000000..15c5290
--- /dev/null
+++ b/engine/humanize.c
@@ -0,0 +1,81 @@
+
+#include <stdlib.h>
+#include <memory.h>
+#include <math.h>
+
+#include "humanize.h"
+
+static inline int ms_to_samples(float ms, int samplerate) {
+ return (int)(ms / 1000.0 * samplerate);
+}
+
+static float gauss(void) {
+ float x = (float)random() / RAND_MAX,
+ y = (float)random() / RAND_MAX,
+ z = sqrtf(-2 * logf(x)) * cosf(2 * M_PI * y);
+ return z;
+}
+
+static float random_normal_distribution(float stddev) {
+ return gauss() * stddev;
+}
+
+// Initialize a humanizer (which tracks a single instrument).
+void humanizer_init(struct humanizer *hum, struct humanizer_settings *settings) {
+ hum->settings = settings;
+ hum->latency_offset = 0;
+ hum->latency_last_pos = 0;
+}
+
+// Return the latency (number of samples) for the next event.
+int humanize_latency_get_next_offset(struct humanizer *hum, int pos) {
+ int latency_max, latency_laid_back;
+ float duration, offset_ms;
+
+ latency_max = ms_to_samples(hum->settings->latency_max_ms, hum->settings->samplerate);
+ latency_laid_back = ms_to_samples(hum->settings->latency_laid_back_ms, hum->settings->samplerate);
+
+ duration = (float)(pos - hum->latency_last_pos) / hum->settings->samplerate;
+ hum->latency_offset *= pow(1.0 - hum->settings->latency_regain, duration);
+ hum->latency_last_pos = pos;
+
+ offset_ms = random_normal_distribution(hum->settings->latency_stddev_ms);
+ hum->latency_offset += ms_to_samples(offset_ms, hum->settings->samplerate);
+ if (hum->latency_offset < -latency_max)
+ hum->latency_offset = -latency_max;
+ if (hum->latency_offset > latency_max)
+ hum->latency_offset = latency_max;
+
+ return latency_max + latency_laid_back + hum->latency_offset;
+}
+
+int humanize_velocity(struct humanizer *hum, int velocity) {
+ float v;
+ int vo;
+
+ v = velocity / 127.0;
+ v *= 1 + random_normal_distribution(hum->settings->velocity_stddev);
+ vo = v * 127;
+ if (vo < 0)
+ vo = 0;
+ if (vo > 127)
+ vo = 127;
+ return vo;
+}
+
+// Initialize humanizer_settings with default (disabled) values.
+void humanizer_settings_init(struct humanizer_settings *settings, int samplerate) {
+ settings->samplerate = samplerate;
+ settings->latency_regain = 1;
+ settings->latency_laid_back_ms = 0;
+ settings->latency_max_ms = 0;
+ settings->latency_stddev_ms = 0;
+ settings->velocity_stddev = 0;
+}
+
+// Returns the maximum latency introduced by the humanizer, so that
+// plugins can compensate for it. This aligns the humanizer 0 time
+// with latency_max_ms.
+int humanize_get_latency(struct humanizer_settings *settings) {
+ return ms_to_samples(settings->latency_max_ms, settings->samplerate);
+}
diff --git a/engine/humanize.h b/engine/humanize.h
new file mode 100644
index 0000000..9353c2f
--- /dev/null
+++ b/engine/humanize.h
@@ -0,0 +1,29 @@
+#ifndef __humanize_H
+#define __humanize_H 1
+
+
+struct humanizer_settings {
+ float samplerate;
+
+ float latency_regain;
+ float latency_laid_back_ms;
+ float latency_max_ms;
+ float latency_stddev_ms;
+
+ float velocity_stddev;
+};
+
+struct humanizer {
+ struct humanizer_settings *settings;
+
+ float latency_offset;
+ int latency_last_pos;
+};
+
+void humanizer_init(struct humanizer *, struct humanizer_settings *);
+void humanizer_settings_init(struct humanizer_settings *, int);
+int humanize_latency_get_next_offset(struct humanizer *, int);
+int humanize_velocity(struct humanizer *, int);
+int humanize_get_latency(struct humanizer_settings *);
+
+#endif
diff --git a/engine/sampler.c b/engine/sampler.c
index d8dccdc..7206b81 100644
--- a/engine/sampler.c
+++ b/engine/sampler.c
@@ -4,15 +4,21 @@
#include "sampler.h"
-struct sampler *sampler_new(int num_voices, int samplerate) {
- struct sampler *sampler = (struct sampler *)calloc(1, sizeof(struct sampler));
+static void init_voices(struct sampler *sampler) {
int i;
+ for (i = 0; i < sampler->num_voices; i++) {
+ voice_init(&sampler->voices[i], sampler->samplerate);
+ }
+}
+struct sampler *sampler_new(int num_voices, int samplerate, struct humanizer_settings *hsettings) {
+ struct sampler *sampler = (struct sampler *)calloc(1, sizeof(struct sampler));
+
+ sampler->hsettings = hsettings;
+ sampler->samplerate = samplerate;
sampler->num_voices = num_voices;
sampler->voices = (struct voice *)calloc(num_voices, sizeof(struct voice));
- for (i = 0; i < num_voices; i++) {
- voice_init(&sampler->voices[i], samplerate);
- }
+ init_voices(sampler);
return sampler;
}
@@ -26,16 +32,26 @@ void sampler_free(struct sampler *sampler) {
}
void sampler_set_drumkit(struct sampler *sampler, struct drumkit *kit) {
+ int i;
+
if (sampler->kit) {
+ // Re-initialize all voices to avoid pending references to freed samples.
+ init_voices(sampler);
drumkit_free(sampler->kit);
free(sampler->kit);
+ free(sampler->humanizers);
}
sampler->kit = kit;
+ sampler->humanizers = (struct humanizer *)calloc(kit->num_instruments, sizeof(struct humanizer));
+ for (i = 0; i < kit->num_instruments; i++) {
+ humanizer_init(&sampler->humanizers[i], sampler->hsettings);
+ }
+ sampler->ticks = 0;
}
void sampler_noteon(struct sampler *sampler, int note, int velocity) {
struct instrument *ins;
- int i;
+ int i, offset;
if (!sampler->kit)
return;
@@ -66,8 +82,11 @@ void sampler_noteon(struct sampler *sampler, int note, int velocity) {
return;
}
- // Humanize: modify preamble.
- voice_noteon(voice, ins, note, velocity, 0);
+ // Humanize: modify preamble and velocity.
+ offset = humanize_latency_get_next_offset(&sampler->humanizers[ins->index], sampler->ticks);
+ velocity = humanize_velocity(&sampler->humanizers[ins->index], velocity);
+
+ voice_noteon(voice, ins, note, velocity, offset);
}
void sampler_noteoff(struct sampler *sampler, int note) {
@@ -90,4 +109,10 @@ void sampler_output(struct sampler *sampler, float *out_l, float *out_r, int num
for (i = 0; i < sampler->num_voices; i++) {
voice_process(&sampler->voices[i], out_l, out_r, num_frames);
}
+
+ sampler->ticks += num_frames;
+}
+
+int sampler_get_latency(struct sampler *sampler) {
+ return humanize_get_latency(sampler->hsettings);
}
diff --git a/engine/sampler.h b/engine/sampler.h
index eb15f26..0115168 100644
--- a/engine/sampler.h
+++ b/engine/sampler.h
@@ -3,18 +3,24 @@
#include "drumkit.h"
#include "voice.h"
+#include "humanize.h"
struct sampler {
struct drumkit *kit;
+ int samplerate;
int num_voices;
struct voice *voices;
+ struct humanizer_settings *hsettings;
+ struct humanizer *humanizers;
+ int ticks;
};
-struct sampler *sampler_new(int, int);
+struct sampler *sampler_new(int, int, struct humanizer_settings *);
void sampler_set_drumkit(struct sampler *, struct drumkit *);
void sampler_free(struct sampler *);
void sampler_noteon(struct sampler *, int, int);
void sampler_noteoff(struct sampler *, int);
void sampler_output(struct sampler *, float *, float *, int);
+int sampler_get_latency(struct sampler *);
#endif
diff --git a/plugin/plugin.c b/plugin/plugin.c
index 0b4864b..89ab72d 100644
--- a/plugin/plugin.c
+++ b/plugin/plugin.c
@@ -46,6 +46,7 @@ struct sampler_plugin {
plugin_uris uris;
+ struct humanizer_settings hsettings;
struct sampler *sampler;
int activated;
@@ -148,7 +149,8 @@ static LV2_Handle instantiate(const LV2_Descriptor *descriptor, double rate,
struct sampler_plugin *plugin =
(struct sampler_plugin *)calloc(1, sizeof(struct sampler_plugin));
- plugin->sampler = sampler_new(NUM_VOICES, (int)rate);
+ humanizer_settings_init(&plugin->hsettings, (int)rate);
+ plugin->sampler = sampler_new(NUM_VOICES, (int)rate, &plugin->hsettings);
plugin->samplerate = (int)rate;
// Get host features
--
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