diff -urN midi_prog-/Makefile midi_prog/Makefile
--- midi_prog-/Makefile	Wed Aug 12 00:00:00 2015
+++ midi_prog/Makefile	Thu Aug 13 00:00:00 2015
@@ -9,7 +9,7 @@
 VCD_OBJS = vcd.o in.o filter.o out.o wrt.o util.o
 VOCO_OBJS = voco.o vco.o wave.o in.o filter.o out.o util.o
 MIDTXT_OBJS = midtxt.o rd.o wrt.o util.o
-TOOL_OBJS = tool.o in.o out.o util.o buf.o pitch.o
+TOOL_OBJS = tool.o in.o out.o util.o buf.o pitch.o pitdet.o
 
 all: $(TARG) vcd voco midtxt tool
 
diff -urN midi_prog-/pitdet.c midi_prog/pitdet.c
--- midi_prog-/pitdet.c	Thu Jan  1 09:00:00 1970
+++ midi_prog/pitdet.c	Thu Aug 13 00:00:00 2015
@@ -0,0 +1,58 @@
+#include "pitdet.h"
+
+double
+pitdet_note_to_freq(double note)
+{
+	return 440 * pow(2, (note - 69) / 12);
+}
+
+double
+pitdet_freq_to_note(double freq)
+{
+	return log(freq / 440) / log(2) * 12 + 69;
+}
+
+void
+pitdet_init(struct pitdet *pd, double smp_freq,
+	    int div, double abuf_wsec)
+{
+	int j;
+
+	pd->div = div;
+	pd->m = pd->div * 128;
+	if((pd->arr = malloc(sizeof(*pd->arr) * pd->m)) == NULL) ERR("No Mem");
+
+	for(j=0; j<pd->m; j++){
+		double note = (double)j / pd->div - 0.5;
+		double next_note = (double)(j+1) / pd->div - 0.5;
+		double freq = pitdet_note_to_freq(note);
+		double next_freq = pitdet_note_to_freq(next_note);
+		int wn = (int) pitch_wn(freq, next_freq);
+
+		pitch_init(&pd->arr[j], smp_freq, freq, wn, abuf_wsec);
+	}
+
+	pd->oldest_sec = -1;
+	pd->newest_sec = -1;
+}
+
+void
+pitdet_add(struct pitdet *pd, double v)
+{
+	int j;
+	double sec;
+
+	pd->oldest_sec = -1;
+	pd->newest_sec = -1;
+
+	for(j=0; j<pd->m; j++){
+		struct pitch *p = &pd->arr[j];
+		pitch_add(p, v);
+
+		sec = tbuf_oldest_sec(&p->ab.tb);
+		if(pd->oldest_sec < 0 || sec > pd->oldest_sec) pd->oldest_sec = sec;
+
+		sec = tbuf_newest_sec(&p->ab.tb);
+		if(pd->newest_sec < 0 || sec < pd->newest_sec) pd->newest_sec = sec;
+	}
+}
diff -urN midi_prog-/pitdet.h midi_prog/pitdet.h
--- midi_prog-/pitdet.h	Thu Jan  1 09:00:00 1970
+++ midi_prog/pitdet.h	Thu Aug 13 00:00:00 2015
@@ -0,0 +1,21 @@
+#ifndef __PITDET_H__
+#define __PITDET_H__
+
+#include "pitch.h"
+
+struct pitdet{
+	int div;
+	int m;
+	struct pitch *arr;
+	double oldest_sec, newest_sec;
+};
+
+double pitdet_note_to_freq(double note);
+double pitdet_freq_to_note(double freq);
+
+void pitdet_init(struct pitdet *pd, double smp_freq,
+		 int div, double abuf_wsec);
+
+void pitdet_add(struct pitdet *pd, double v);
+
+#endif
diff -urN midi_prog-/tool.c midi_prog/tool.c
--- midi_prog-/tool.c	Wed Aug 12 00:00:00 2015
+++ midi_prog/tool.c	Thu Aug 13 00:00:00 2015
@@ -1,6 +1,6 @@
 #include "util.h"
 #include "in.h"
-#include "pitch.h"
+#include "pitdet.h"
 
 int
 main(int ac, char **av)
@@ -8,22 +8,22 @@
 	in_rec_t in;
 	double v;
 
-	struct pitch p;
-	double freq = 440.0;
-	double next_freq = 440 * pow(2, (70-69)/12.0);
-	int wn = (int) pitch_wn(freq, next_freq);
+	struct pitdet pd;
+	int div = opt_int("-div", ac, av, 1);
 	double abuf_wsec = opt_double("-abuf_wsec", ac, av, 0.5);
-	double sec, sec_bak = -1;
+	double old_bak = 0, new_bak = 0;
 
 	in_init(&in, ac, av);
-	pitch_init(&p, in.smp_freq, freq, wn, abuf_wsec);
+	pitdet_init(&pd, in.smp_freq, div, abuf_wsec);
 
 	while(in_do_mono(&in, &v) != EOF){
-		pitch_add(&p, v);
-		sec = tbuf_newest_sec(&p.ab.tb);
-		if(sec <= sec_bak) continue;
-		printf("sec=%f v=%f\n", sec, p.ab.sum);
-		sec_bak = sec;
+		pitdet_add(&pd, v);
+		if( pd.oldest_sec > 0 && pd.newest_sec > 0 &&
+		    (pd.oldest_sec > old_bak || pd.newest_sec > new_bak) ){
+			printf("%f %f\n", pd.oldest_sec, pd.newest_sec);
+			old_bak = pd.oldest_sec;
+			new_bak = pd.newest_sec;
+		}
 	}
 	return 0;
 }