Events given start times in ms

Author: Cornerback24

MidiData.py

@@ -20,11 +20,12 @@ def __init__(self, midiFilename):
             self.ticksPerBeat = headerData.ticksPerBeat
 
         #maps running total of delta times to microsecondsPerQuarter
-        self.tempoChanges = TempoChanges()
+        tempoChanges = TempoChanges()
         self.trackZeroEvents = []
         self.tracks = []
 
-        deltaTimeTotal = 0    
+        deltaTimeTotal = 0
+        self.msPerBeat = 500 #default 120 bpm
         #should be a track header
         event = self.eventDecoder.nextEvent()
 
@@ -36,7 +37,7 @@ def __init__(self, midiFilename):
             self.trackZeroEvents.append(event)
             if (event.eventClass == "Meta" and
                 event.eventType == "SetTempo"):
-                self.tempoChanges.addTempoChange(deltaTimeTotal, event)
+                tempoChanges.addTempoChange(deltaTimeTotal, event)
 
 
         #read in each track
@@ -47,14 +48,42 @@ def __init__(self, midiFilename):
             #should be a track header
             event = self.eventDecoder.nextEvent()
             trackData = TrackData(trackName)
+            #set up tempoChanges
+            tempoChanges.reset()
+            deltaTimeTotal = 0
+            nextTotal = 0
+            msTotal = 0 #current time in ms
+            while (tempoChanges.hasMore() and
+                   tempoChanges.deltaTimeTotal() == 0):
+                self.msPerBeat = tempoChanges.usPerQuarter()*.001
+                tempoChanges.findNext()
+            #add events
             while not(event.eventClass == "Meta"
                 and event.eventType == "EndOfTrack"):
                 event = self.eventDecoder.nextEvent()
+                nextTotal = deltaTimeTotal + event.deltaTime
+                #calcaute absolute start time for event in ms
+                if self.isTicksPerBeat:
+                    while (tempoChanges.hasMore() and
+                           nextTotal > tempoChanges.deltaTimeTotal()):
+                        msTotal = msTotal + ((tempoChanges.deltaTimeTotal() -
+                                     deltaTimeTotal)*self.msPerBeat/self.ticksPerBeat)
+                        deltaTimeTotal = (tempoChanges.deltaTimeTotal() -
+                                     deltaTimeTotal) + deltaTimeTotal
+                        tempoChanges.findNext()
+                        self.msPerBeat = tempoChanges.usPerQuarter()*.001
+                    msTotal = (msTotal +
+                           ((nextTotal-deltaTimeTotal)*self.msPerBeat/self.ticksPerBeat))
+                else:
+                    msTotal = (event.deltaTime/self.ticksPerSecond)*.001
+                #add event to trackData
+                deltaTimeTotal = nextTotal
+                event.setStartTime(msTotal)
                 trackData.addEvent(event)
             self.tracks.append(trackData)
 
 #this line just for testing
-MidiData("testMidiFile.mid")
+MidiData("Magic Battle.mid")
 
 
 

MidiEventDecoder.py

@@ -65,6 +65,8 @@ def __init__(self, deltaTime, midiData):
     def __str__(self):
         return (self.eventClass + " " + str(self.midiData) +
                 " deltaTime: " + str(self.deltaTime))
+    def setStartTime(self, startTime): #set start time in ms
+        self.startTime = startTime
 
 #contains data from the header chunk
 class HeaderData:
@@ -117,7 +119,7 @@ def __init__(self, deltaTime, midiData):
             self.sequenceNumber = int.from_bytes(midiData[3:], "big")
         if self.eventType == "SetTempo":
             #micro seconds per quarter note
-            self.usPerQuarter = int.from_bytes(midiData[4:], "big")
+            self.usPerQuarter = int.from_bytes(midiData[3:], "big")
     def __str__(self):
         s = ("Meta " + str(self.midiData) + " deltaTime: "
                 + str(self.deltaTime) + " eventType: " + self.eventType)

TrackData.py

@@ -12,24 +12,25 @@ def addEvent(self, event):
             self.name = event.data
         return
 
-#this is basiclly and ordered dictionary
+#this is kind of like an ordered dictionary
 class TempoChanges:
     def __init__(self):
-        self.deltaTimeTotal = []
+        self.deltaTimeTotals = []
         self.tempoChangeEvents = []
         self.index = 0
         return
     #tempo changes need to be added in order
     def addTempoChange(self, deltaTimeTotal, event):
-        self.deltaTimeTotal.append(deltaTimeTotal)
+        self.deltaTimeTotals.append(deltaTimeTotal)
         self.tempoChangeEvents.append(event)
     #so that class can be used as a stream
-    def current(self):
-        return (self.deltaTimeTotal[self.index],
-                self.tempoChangeEvets[self.index])
+    def deltaTimeTotal(self):
+        return self.deltaTimeTotals[self.index]
+    def usPerQuarter(self):
+        return self.tempoChangeEvents[self.index].usPerQuarter
     def findNext(self):
         self.index = self.index + 1
-    def hasMoreTempoChanges(self):
-        return self.index < len(self.tempoChangeEvents)
-    def reset(self): #go back to first task
+    def hasMore(self):
+        return self.index + 1 < len(self.tempoChangeEvents)
+    def reset(self): #go back to first tempo change
         self.index = 0