@udalilprofile
I tried to do it in FAUST, then the value in the UI must be made with a global_cable and draw its value in a panel.
import("stdfaust.lib");
//==============================================================================
// CORRELATION METER
//
// A stereo phase correlation meter that outputs a value between -1 and +1
// indicating the phase relationship between left and right channels.
//
// +1 = fully correlated (mono)
// 0 = fully decorrelated (wide stereo)
// -1 = fully anti-correlated (out of phase)
//==============================================================================
// Integration time constant (in seconds) - typical range 10-100ms
integration_time = hslider("Integration Time", 0.05, 0.01, 0.2, 0.001);
// Small constant to prevent division by zero
epsilon = 1e-10; // FAUST has a function for this but I'm lost and would like to close the implementation -.-'
// Low-pass filter cutoff frequency based on integration time
lpf_freq = 1.0 / (2.0 * ma.PI * integration_time);
// Basic correlation meter implementation
correlation_meter = _ , _ : correlation_calc
with {
correlation_calc(l, r) = lr_filtered / (sqrt(l2_filtered * r2_filtered) + epsilon)
with {
// Cross-correlation term (L * R)
lr_filtered = (l * r) : fi.lowpass(1, lpf_freq);
// Auto-correlation terms (L² and R²)
l2_filtered = (l * l) : fi.lowpass(1, lpf_freq);
r2_filtered = (r * r) : fi.lowpass(1, lpf_freq);
};
};
// Alternative implementation using sum/difference method
correlation_meter_alt = _ , _ : correlation_calc_alt
with {
correlation_calc_alt(l, r) = (sum_power - diff_power) / (sum_power + diff_power + epsilon)
with {
sum_sig = (l + r) * 0.5;
diff_sig = (l - r) * 0.5;
sum_power = (sum_sig * sum_sig) : fi.lowpass(1, lpf_freq);
diff_power = (diff_sig * diff_sig) : fi.lowpass(1, lpf_freq);
};
};
// Algorithm selector
algorithm = nentry("Algorithm", 0, 0, 1, 1);
// Main correlation calculation with algorithm selection
correlation_calc = _ , _ <: (correlation_meter, correlation_meter_alt) : select2(algorithm);
// Correlation meter with UI elements - following the vumeter pattern
cmeter(l, r) = attach(l, correlation_calc(l, r) : hbargraph("Correlation", -1, 1)), r;
// Process function - stereo input, stereo passthrough with correlation display
process = cmeter;
Two different correlation calculation:
Direct method using L*R / sqrt(L² * R²)
Sum/difference method using (S² - D²) / (S² + D²)
Adjustable parameters:
Integration time (10ms to 200ms)
Algorithm selection
Real-time display:
Horizontal bargraph showing correlation value
As for the implementation in HISE (UI) you need to connect the hbargraph in a
global_cable scriptnode and draw the "bar" in a panel - this is more complicated for me 😧
Since I'm still a newbie, it would be a good idea to properly test the implementation before putting it "into production"
