From eacd887c25d1ddde6f165513e9fd1f4a0c5b8afc Mon Sep 17 00:00:00 2001
From: "sgunderson@bigfoot.com" <>
Date: Thu, 28 Dec 2006 14:46:25 +0100
Subject: [PATCH] Fix quite a few bad bugs in the skew estimation.

---
 estimate-skew.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/estimate-skew.c b/estimate-skew.c
index 1c44f86..d2991fc 100644
--- a/estimate-skew.c
+++ b/estimate-skew.c
@@ -11,7 +11,7 @@ double frac(double x)
 double filter(double x)
 {
 	static double l = 0.0;
-	l = 0.001 * x + 0.999 * l;
+	l = 0.01 * x + 0.99 * l;
 	return l;
 }
 
@@ -58,8 +58,10 @@ int main(int argc, char **argv)
 	double speed = 1.0;
 
 	while (!feof(in1) && !feof(in2)) {
+		short refs;
+
 		// read sample from reference
-		if (fread(&sample, sizeof(short), 1, in1) != 1) {
+		if (fread(&refs, sizeof(short), 1, in1) != 1) {
 			exit(0);
 		}
 
@@ -75,14 +77,14 @@ int main(int argc, char **argv)
 
 		// linear interpolation (works well since delta_p varies so slowly)
 		double t = frac(p);
-		short intp_sample = prev_sample * (1.0 - t) + sample * t;
+		double intp_sample = prev_sample * (1.0 - t) + sample * t;
 
 		// subtract the two samples and pull it through a filter. we assume
 		// the sines are normalized for now (and that there's no dc skew)
-		double offset = -0.001 * filter(intp_sample - sample);
-		speed += offset;
+		double offset = filter(intp_sample - refs);
+		speed -= 0.00000001 * offset;
 		fwrite(&speed, sizeof(double), 1, skew);
 
-		printf("%f (offset=%f)\n", speed, offset);
+		printf("%f (offset=%f)\n", speed, intp_sample - sample);
 	}
 }
-- 
2.39.2