Switch latency_stddev to be samplerate independent (and thus in ms).

Visualization seems correct but I didn't verify the math.

3 files changed, 14 insertions, 21 deletions

diff --git a/src/latencyfilter.cc b/src/latencyfilter.cc
index abb67cd..9410b50 100644
--- a/src/latencyfilter.cc
+++ b/src/latencyfilter.cc
@@ -73,21 +73,14 @@ bool LatencyFilter::filter(event_t& event, std::size_t pos)
 
 	latency_last_pos = pos;
 
-	float offset_min = latency * -1.0f;
-	float offset_max = latency * 1.0f;
-
-	float mean = 0.0f;//latency_laid_back;
-	float stddev = latency_stddev;
-
-	float offset = random.normalDistribution(mean, stddev);
-
-	latency_offset += offset;
-
-	if(latency_offset > offset_max) latency_offset = offset_max;
-	if(latency_offset < offset_min) latency_offset = offset_min;
+	float offset_min = -latency;
+	float offset_max = latency;
+	float offset_ms = random.normalDistribution(0.0f, latency_stddev);
+	latency_offset += getLatencySamples(offset_ms, samplerate);
+	latency_offset = std::max(offset_min, std::min(offset_max, latency_offset));
 
 	DEBUG(offset, "latency: %d, offset: %f, drift: %f",
-	      (int)latency, offset, latency_offset);
+	      (int)latency, offset_ms, latency_offset);
 
 	event.offset += latency; // fixed latency offset
 	event.offset += latency_laid_back; // laid back offset (user controlled)
diff --git a/src/latencyfilter.h b/src/latencyfilter.h
index a49dd47..8191276 100644
--- a/src/latencyfilter.h
+++ b/src/latencyfilter.h
@@ -44,6 +44,6 @@ public:
 private:
 	Settings& settings;
 	Random& random;
-	double latency_offset{0.0};
+	float latency_offset{0.0};
 	std::size_t latency_last_pos{0};
 };
diff --git a/src/settings.h b/src/settings.h
index 6b4048c..f37a810 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -111,13 +111,13 @@ struct Settings
 	static float constexpr latency_laid_back_ms_default = 0.0f;
 	Atomic<float> latency_laid_back_ms{latency_laid_back_ms_default};
 
-	//!   0 := Robot
-	//! 100 := Good drummer
-	//! 200 := Decent drummer
-	//! 300 := Decent drummer on a bad day
-	//! 400 := Bad drummer
-	//! 500 := Bad and drunk drummer
-	static float constexpr latency_stddev_default = 100.0f;
+	//! 0.0 := Robot
+	//! 2.0 := Good drummer
+	//! 4.0 := Decent drummer
+	//! 6.0 := Decent drummer on a bad day
+	//! 8.0 := Bad drummer
+	//! 10.0 := Bad and drunk drummer
+	static float constexpr latency_stddev_default = 2.0f;
 	Atomic<float> latency_stddev{latency_stddev_default};
 
 	//! Regain on-beat position.