diff -ur v3/snddiv.py v4/snddiv.py
--- v3/snddiv.py	2020-01-20 12:13:42.792518000 +0900
+++ v4/snddiv.py	2020-01-20 12:58:17.171850000 +0900
@@ -149,7 +149,7 @@
 
 	proc = proc_new()
 	rth = thr.loop_new( rfunc, ( proc.get_stderr(), ) )
-	wth = thr.th_new( wfunc, ( proc.get_stdin(), ) )	
+	wth = thr.th_new( wfunc, ( proc.get_stdin(), ) )
 
 	def start():
 		e.run = True
@@ -165,6 +165,39 @@
 
 	return empty.to_attr( e, locals() )
 
+def snd_new(data, sudo_passwd):
+	opt = data.opt
+
+	e = empty.new()
+	e.sec = 0
+	e.play = None
+	e.reverse = False
+	e.shift = 0
+
+	def get_sec():
+		add = 0
+		if e.play:
+			add = e.play.sec * 2**e.shift
+			if e.reverse:
+				add = -add
+		return e.sec + add
+
+	def start():
+		if e.play:
+			stop()
+		dat = data.get_dat_sec( e.sec, e.reverse, max(e.shift, 0) )
+		e.play = play_new( dat, opt, sudo_passwd, min(2**e.shift, 1.0) )
+		e.play.start()
+
+	def stop():
+		if not e.play:
+			return
+		e.play.stop()
+		e.sec = get_sec()
+		e.play = None
+
+	return empty.to_attr( e, locals() )
+
 def get_args():
 	av = sys.argv[1:]
 	k = '-S'
@@ -184,9 +217,7 @@
 	data = data_new(filename_mp3)
 	dbg.out( 'last_sec={}'.format( data.last_sec ) )
 
-	opt = data.opt
-	dat = data.get_dat_sec(10, False)
-	play = play_new(dat, opt, sudo_passwd)
+	snd = snd_new(data, sudo_passwd)
 
 	while True:
 		dbg.out('snd> ', '')