diff -urN midi_prog-/buf.c midi_prog/buf.c
--- midi_prog-/buf.c	Thu Aug 27 00:00:00 2015
+++ midi_prog/buf.c	Wed Sep  9 00:00:00 2015
@@ -309,11 +309,33 @@
 double
 abuf_mean(struct abuf *ab, double from_sec, double to_sec)
 {
-	int from_i = (int) tbuf_sec_to_sridx(&ab->tb, from_sec);
-	int to_i = (int) tbuf_sec_to_sridx(&ab->tb, to_sec);
+	struct tbuf *tb = &ab->tb;
+	struct rbuf *rb = &tb->rb;
+	int from_i = (int) tbuf_sec_to_sridx(tb, from_sec);
+	int to_i = (int) tbuf_sec_to_sridx(tb, to_sec);
 	int i;
 	double sum = 0;
 	if(from_i >= to_i) return 0;
-	for(i=from_i; i<to_i; i++) sum += rbuf_get_dbl(&ab->tb.rb, i);
+	for(i=from_i; i<to_i; i++) sum += rbuf_get_dbl(rb, i);
 	return sum / (to_i - from_i);
+}
+
+double
+abuf_max(struct abuf *ab, double from_sec, double to_sec, double *ret_sec)
+{
+	struct tbuf *tb = &ab->tb;
+	struct rbuf *rb = &tb->rb;
+	int from_i = (int) tbuf_sec_to_sridx(tb, from_sec);
+	int to_i = (int) tbuf_sec_to_sridx(tb, to_sec);
+	int i = from_i, t = i;
+	double v, tv = rbuf_get_dbl(rb, i);
+
+	for(i++; i<to_i; i++){
+		if((v = rbuf_get_dbl(rb, i)) > tv){
+			tv = v;
+			t = i;
+		}
+	}
+	if(ret_sec) *ret_sec = tbuf_sridx_to_sec(tb, t);
+	return tv;
 }
diff -urN midi_prog-/buf.h midi_prog/buf.h
--- midi_prog-/buf.h	Thu Aug 27 00:00:00 2015
+++ midi_prog/buf.h	Wed Sep  9 00:00:00 2015
@@ -86,5 +86,6 @@
 void abuf_init(struct abuf *ab, double smp_freq, double wsec);
 void abuf_add(struct abuf *ab, double v);
 double abuf_mean(struct abuf *ab, double from_sec, double to_sec);
+double abuf_max(struct abuf *ab, double from_sec, double to_sec, double *ret_sec);
 
 #endif
diff -urN midi_prog-/pitdet.c midi_prog/pitdet.c
--- midi_prog-/pitdet.c	Tue Sep  8 00:00:00 2015
+++ midi_prog/pitdet.c	Wed Sep  9 00:00:00 2015
@@ -206,5 +206,5 @@
 int
 pitdet_onoff_judge(struct pitdet *pd, double v)
 {
-	return v / pd->max_v >= pd->thres;
+	return v >= pd->thres * pd->max_v;
 }
diff -urN midi_prog-/tool.c midi_prog/tool.c
--- midi_prog-/tool.c	Tue Sep  8 00:00:00 2015
+++ midi_prog/tool.c	Wed Sep  9 00:00:00 2015
@@ -100,13 +100,15 @@
 }
 
 struct note_onoff{
-	struct chatt ct;
+	struct chatt ct, ct2;
 	struct abuf ab;
 	struct pitdet *pd;
 	int note;
 	double on_sec;
 	double pre_release;
 	int cut_over_tone;
+	double peak, peak_thres;
+	int onoff;
 } note_onoff[ NOTE_N ];
 
 void
@@ -120,6 +122,11 @@
 	nto->on_sec = -1;
 	nto->pre_release = opt_double("-pre_release", ac, av, 0);
 	nto->cut_over_tone = opt_idx("-cut_over_tone", ac, av) > 0;
+
+	chatt_init(&nto->ct2, lmt_sec);
+	nto->peak = -1;
+	nto->peak_thres = opt_double("-peak_thres", ac, av, 0.1);
+	nto->onoff = 0;
 }
 
 double
@@ -167,20 +174,43 @@
 {
 	double on_sec, off_sec;
 	int tick, velo;
+	int chg, chg2, chg_a = -1;
 
 	abuf_add(&nto->ab, v);
 
-	if(!chatt_add(&nto->ct, sec, onoff)) return;
-
-	if(nto->ct.onoff){
-		nto->on_sec = nto->ct.sec;
-		return;
+	chg = chatt_add(&nto->ct, sec, onoff);
+	if(nto->peak >= 0){
+		nto->peak = MAX(nto->peak, v);
+		chg2 = chatt_add(&nto->ct2, sec, v > nto->peak * nto->peak_thres);
 	}
 
+	if(!nto->onoff){
+		if(nto->peak >= 0 && chg2 && nto->ct2.onoff){
+			nto->on_sec = nto->ct2.sec;
+			chg_a = 1;
+		}else if(chg && nto->ct.onoff){
+			nto->on_sec = nto->ct.sec;
+			chg_a = 1;
+
+			nto->peak = abuf_max(&nto->ab, nto->on_sec, sec, NULL);
+			chatt_set(&nto->ct2, 1);
+		}
+	}else{
+		if(chg && !nto->ct.onoff){
+			off_sec = nto->ct.sec;
+			chg_a = 0;
+
+			nto->peak = -1;
+		}else if(chg2 && !nto->ct2.onoff){
+			off_sec = nto->ct2.sec;
+			chg_a = 0;
+		}
+	}
+	if(chg_a < 0) return;
+	if((nto->onoff = chg_a) > 0) return;
 	if(nto->on_sec < 0) return;
 
 	on_sec = nto->on_sec;
-	off_sec = nto->ct.sec;
 	nto->on_sec = -1;
 
 	if(nto->pre_release > 0){
@@ -218,7 +248,7 @@
 			v = pitdet_get(pd, j, sec);
 			int o = pitdet_onoff_judge(pd, v);
 			onoff |= o;
-			if(o) sum += v;
+			if(o) sum += MAX(v, 0);
 		}
 		v = sum;
 		note_onoff_add(&note_onoff[i], sec, onoff, v, ch);
diff -urN midi_prog-/util.c midi_prog/util.c
--- midi_prog-/util.c	Sat Sep  5 00:00:00 2015
+++ midi_prog/util.c	Wed Sep  9 00:00:00 2015
@@ -191,4 +191,11 @@
 	return 1;
 }
 
+void
+chatt_set(struct chatt *ct, int onoff)
+{
+	ct->onoff = onoff;
+	ct->chg_try_sec = -1;
+}
+
 /* EOF */
diff -urN midi_prog-/util.h midi_prog/util.h
--- midi_prog-/util.h	Sat Aug 29 00:00:00 2015
+++ midi_prog/util.h	Wed Sep  9 00:00:00 2015
@@ -56,5 +56,6 @@
 
 void chatt_init(struct chatt *ct, double lmt_sec);
 int chatt_add(struct chatt *ct, double sec, int onoff);
+void chatt_set(struct chatt *ct, int onoff);
 
 #endif