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Add minimal JACK host for real-time effect testing (fixes #31) #51

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Add minimal JACK host for real-time effect testing (fixes #31) #51

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4 changes: 4 additions & 0 deletions Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,10 @@ convert.o: $(HEADERS)

convert: convert.o

# JACK host for real-time effect testing (requires libjack-dev)
jack_host: jack_host.c $(HEADERS)
$(CC) $(CFLAGS) -o $@ $< -ljack $(LDLIBS)

output.raw: input.raw convert
./convert echo $(echo_defaults) < input.raw > output.raw

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203 changes: 203 additions & 0 deletions jack_host.c
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@@ -0,0 +1,203 @@
//
// Minimal JACK host for AudioNoise effects
// Allows testing effects in real-time without hardware
//
// Inspired by prior work from @phstrauss:
// - jclient.h: https://gist.github.com/phstrauss/e6c449b337fc6b20ebd7937001589f3d
// - jclient.c: https://gist.github.com/phstrauss/8fdef23b4749b7f6dc883444c4853d3f
// - jack_passthru.c: https://gist.github.com/phstrauss/...
//
// Build: gcc -o jack_host jack_host.c -ljack -lm
// or: make jack_host
//
// Usage: ./jack_host <effect> <pot1> <pot2> <pot3> <pot4>
//
// Then connect with: jack_connect system:capture_1 audionoise:input
// jack_connect audionoise:output system:playback_1
//

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <math.h>
#include <jack/jack.h>

typedef int s32;
typedef unsigned int u32;
typedef unsigned int uint;

#define SAMPLES_PER_SEC (48000.0)

// Core utility functions and helpers
#include "util.h"
#include "lfo.h"
#include "effect.h"
#include "biquad.h"

// Effects
#include "flanger.h"
#include "echo.h"
#include "fm.h"
#include "am.h"
#include "phaser.h"
#include "discont.h"
#include "distortion.h"

#define EFF(x) { #x, x##_init, x##_step }
struct effect {
const char *name;
void (*init)(float,float,float,float);
float (*step)(float);
} effects[] = {
EFF(discont),
EFF(distortion),
EFF(echo),
EFF(flanger),
EFF(phaser),

/* "Helper" effects */
EFF(am),
EFF(fm),
};

#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))

static jack_client_t *client;
static jack_port_t *input_port;
static jack_port_t *output_port;
static struct effect *current_effect = &effects[0];
static volatile int running = 1;

// JACK process callback - called for each audio buffer
static int process_callback(jack_nframes_t nframes, void *arg)
{
jack_default_audio_sample_t *in = jack_port_get_buffer(input_port, nframes);
jack_default_audio_sample_t *out = jack_port_get_buffer(output_port, nframes);

for (jack_nframes_t i = 0; i < nframes; i++) {
UPDATE(effect_delay);
out[i] = current_effect->step(in[i]);
}

return 0;
}

// Handle JACK shutdown
static void jack_shutdown(void *arg)
{
fprintf(stderr, "JACK server shut down\n");
running = 0;
}

// Handle Ctrl+C
static void signal_handler(int sig)
{
fprintf(stderr, "\nShutting down...\n");
running = 0;
}

static void print_usage(const char *progname)
{
fprintf(stderr, "Usage: %s <effect> <pot1> <pot2> <pot3> <pot4>\n\n", progname);
fprintf(stderr, "Available effects:\n");
for (int i = 0; i < ARRAY_SIZE(effects); i++) {
fprintf(stderr, " %s\n", effects[i].name);
}
fprintf(stderr, "\nAfter starting, connect ports with:\n");
fprintf(stderr, " jack_connect system:capture_1 audionoise:input\n");
fprintf(stderr, " jack_connect audionoise:output system:playback_1\n");
}

int main(int argc, char **argv)
{
jack_status_t status;
float pot[4];

if (argc < 6) {
print_usage(argv[0]);
return 1;
}

// Find effect
const char *effect_name = argv[1];
int found = 0;
for (int i = 0; i < ARRAY_SIZE(effects); i++) {
if (!strcmp(effect_name, effects[i].name)) {
current_effect = &effects[i];
found = 1;
break;
}
}

if (!found) {
fprintf(stderr, "Unknown effect: %s\n", effect_name);
print_usage(argv[0]);
return 1;
}

// Parse pot values
for (int i = 0; i < 4; i++) {
pot[i] = atof(argv[2 + i]);
}

// Initialize effect
fprintf(stderr, "Initializing %s(%f, %f, %f, %f)\n",
current_effect->name, pot[0], pot[1], pot[2], pot[3]);
current_effect->init(pot[0], pot[1], pot[2], pot[3]);

// Set up signal handler
signal(SIGINT, signal_handler);
signal(SIGTERM, signal_handler);

// Open JACK client
client = jack_client_open("audionoise", JackNullOption, &status);
if (!client) {
fprintf(stderr, "Failed to connect to JACK server\n");
return 1;
}

// Check sample rate
jack_nframes_t sr = jack_get_sample_rate(client);
if (sr != 48000) {
fprintf(stderr, "Warning: JACK sample rate is %d, effects expect 48000\n", sr);
}

// Set callbacks
jack_set_process_callback(client, process_callback, NULL);
jack_on_shutdown(client, jack_shutdown, NULL);

// Create ports
input_port = jack_port_register(client, "input",
JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0);
output_port = jack_port_register(client, "output",
JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);

if (!input_port || !output_port) {
fprintf(stderr, "Failed to create JACK ports\n");
jack_client_close(client);
return 1;
}

// Activate client
if (jack_activate(client)) {
fprintf(stderr, "Failed to activate JACK client\n");
jack_client_close(client);
return 1;
}

fprintf(stderr, "JACK host running. Connect ports and play audio.\n");
fprintf(stderr, "Press Ctrl+C to quit.\n");

// Main loop - just wait for signal
while (running) {
sleep(1);
}

// Cleanup
jack_client_close(client);
fprintf(stderr, "Goodbye!\n");

return 0;
}