diff --git a/src/main/java/com/khjxiaogu/factorio/composer/midi/MidiSheet.java b/src/main/java/com/khjxiaogu/factorio/composer/midi/MidiSheet.java
index 29010ca..f7bf823 100644
--- a/src/main/java/com/khjxiaogu/factorio/composer/midi/MidiSheet.java
+++ b/src/main/java/com/khjxiaogu/factorio/composer/midi/MidiSheet.java
@@ -62,6 +62,8 @@ public MidiSheet(File f, int offset, float speed) throws InvalidMidiDataExceptio
 			NoteTrack currentTrack = new NoteTrack();
 			double beatsPerMinute = 120;
 			//int b = 0;
+			long lastOffset=0;
+			long lastTick=0;
 			if (track.size() > 0) {
 				for (int i = 0; i < track.size(); i++) {
 					double millisPerMidiTick;
@@ -75,9 +77,11 @@ public MidiSheet(File f, int offset, float speed) throws InvalidMidiDataExceptio
 					MidiMessage message = event.getMessage();
 					if (message instanceof ShortMessage) {
 						ShortMessage sm = (ShortMessage) message;
-						if ((sm.getCommand()&0x90)>0) {// Detect KEY_ON message
-							currentTrack.add(sm.getData1() + offset * 12,
-									Math.round(event.getTick() * millisPerMidiTick / MsPerGameTick), sm.getData2());
+						if ((sm.getCommand() & ShortMessage.NOTE_ON) > 0) {// Detect KEY_ON message
+							long delta=event.getTick()-lastTick;
+							lastTick=event.getTick();
+							lastOffset+=Math.round(delta * millisPerMidiTick / MsPerGameTick);
+							currentTrack.add(sm.getData1() + offset * 12,lastOffset, sm.getData2());
 						}
 					} else if (message instanceof MetaMessage) {
 						MetaMessage metaMessage = (MetaMessage) message;