/// <summary>
/// Constructs a MidiEvent from a BinaryStream
/// </summary>
/// <param name="br">The binary stream of MIDI data</param>
/// <param name="previous">The previous MIDI event (pass null for first event)</param>
/// <returns>A new MidiEvent</returns>
public static MidiEvent ReadNextEvent(BinaryReader br, MidiEvent previous)
{
int deltaTime = MidiEvent.ReadVarInt(br);
MidiCommandCode commandCode;
int channel = 1;
byte b = br.ReadByte();
if((b & 0x80) == 0)
{
// a running command - command & channel are same as previous
commandCode = previous.CommandCode;
channel = previous.Channel;
br.BaseStream.Position--; // need to push this back
}
else
{
if((b & 0xF0) == 0xF0)
{
// both bytes are used for command code in this case
commandCode = (MidiCommandCode) b;
}
else
{
commandCode = (MidiCommandCode) (b & 0xF0);
channel = (b & 0x0F) + 1;
}
}
MidiEvent me;
switch(commandCode)
{
case MidiCommandCode.NoteOn:
me = new NoteOnEvent(br);
break;
case MidiCommandCode.NoteOff:
case MidiCommandCode.KeyAfterTouch:
me = new NoteEvent(br);
break;
case MidiCommandCode.ControlChange:
me = new ControlChangeEvent(br);
break;
case MidiCommandCode.PatchChange:
me = new PatchChangeEvent(br);
break;
case MidiCommandCode.ChannelAfterTouch:
me = new ChannelAfterTouchEvent(br);
break;
case MidiCommandCode.PitchWheelChange:
me = new PitchWheelChangeEvent(br);
break;
case MidiCommandCode.TimingClock:
case MidiCommandCode.StartSequence:
case MidiCommandCode.ContinueSequence:
case MidiCommandCode.StopSequence:
me = new MidiEvent();
break;
case MidiCommandCode.Sysex:
me = SysexEvent.ReadSysexEvent(br);
break;
case MidiCommandCode.MetaEvent:
me = MetaEvent.ReadMetaEvent(br);
break;
default:
throw new FormatException(String.Format("Unsupported MIDI Command Code {0:X2}",(byte) commandCode));
}
me.channel = channel;
me.deltaTime = deltaTime;
me.commandCode = commandCode;
return me;
}
/// <summary>
/// Determines if this is an end track event
/// </summary>
public static bool IsEndTrack(MidiEvent midiEvent)
{
if (midiEvent != null)
{
MetaEvent me = midiEvent as MetaEvent;
if (me != null)
{
return me.MetaEventType == MetaEventType.EndTrack;
}
}
return false;
}
/// <summary>
/// Creates a MidiEvent from a raw message received using
/// the MME MIDI In APIs
/// </summary>
/// <param name="rawMessage">The short MIDI message</param>
/// <returns>A new MIDI Event</returns>
public static MidiEvent FromRawMessage(int rawMessage)
{
long absoluteTime = 0;
int b = rawMessage & 0xFF;
int data1 = (rawMessage >> 8) & 0xFF;
int data2 = (rawMessage >> 16) & 0xFF;
MidiCommandCode commandCode;
int channel = 1;
if ((b & 0xF0) == 0xF0)
{
// both bytes are used for command code in this case
commandCode = (MidiCommandCode)b;
}
else
{
commandCode = (MidiCommandCode)(b & 0xF0);
channel = (b & 0x0F) + 1;
}
MidiEvent me;
switch (commandCode)
{
case MidiCommandCode.NoteOn:
case MidiCommandCode.NoteOff:
case MidiCommandCode.KeyAfterTouch:
if (data2 > 0 && commandCode == MidiCommandCode.NoteOn)
{
me = new NoteOnEvent(absoluteTime, channel, data1, data2, 0);
}
else
{
me = new NoteEvent(absoluteTime, channel, commandCode, data1, data2);
}
break;
case MidiCommandCode.ControlChange:
me = new ControlChangeEvent(absoluteTime,channel,(MidiController)data1,data2);
break;
case MidiCommandCode.PatchChange:
me = new PatchChangeEvent(absoluteTime,channel,data1);
break;
case MidiCommandCode.ChannelAfterTouch:
me = new ChannelAfterTouchEvent(absoluteTime,channel,data1);
break;
case MidiCommandCode.PitchWheelChange:
me = new PitchWheelChangeEvent(absoluteTime, channel, data1 + (data2 << 7));
break;
case MidiCommandCode.TimingClock:
case MidiCommandCode.StartSequence:
case MidiCommandCode.ContinueSequence:
case MidiCommandCode.StopSequence:
case MidiCommandCode.AutoSensing:
me = new MidiEvent(absoluteTime,channel,commandCode);
break;
case MidiCommandCode.MetaEvent:
case MidiCommandCode.Sysex:
default:
throw new FormatException(String.Format("Unsupported MIDI Command Code for Raw Message {0}", commandCode));
}
return me;
}
/// <summary>
/// Whether this is a note on event
/// </summary>
public static bool IsNoteOn(MidiEvent midiEvent)
{
if (midiEvent != null)
{
if (midiEvent.CommandCode == MidiCommandCode.NoteOn)
{
NoteEvent ne = (NoteEvent)midiEvent;
return (ne.Velocity > 0);
}
}
return false;
}
/// <summary>
/// Opens a MIDI file for reading
/// </summary>
/// <param name="filename">Name of MIDI file</param>
/// <param name="strictChecking">If true will error on non-paired note events</param>
public MidiFile(string filename, bool strictChecking)
{
this.strictChecking = strictChecking;
var br = new BinaryReader(File.OpenRead(filename));
using (br)
{
string chunkHeader = Encoding.UTF8.GetString(br.ReadBytes(4));
if (chunkHeader != "MThd")
{
throw new FormatException("Not a MIDI file - header chunk missing");
}
uint chunkSize = SwapUInt32(br.ReadUInt32());
if (chunkSize != 6)
{
throw new FormatException("Unexpected header chunk length");
}
// 0 = single track, 1 = multi-track synchronous, 2 = multi-track asynchronous
fileFormat = SwapUInt16(br.ReadUInt16());
int tracks = SwapUInt16(br.ReadUInt16());
deltaTicksPerQuarterNote = SwapUInt16(br.ReadUInt16());
events = new MidiEventCollection((fileFormat == 0) ? 0 : 1, deltaTicksPerQuarterNote);
for (int n = 0; n < tracks; n++)
{
events.AddTrack();
}
long absoluteTime = 0;
for (int track = 0; track < tracks; track++)
{
if (fileFormat == 1)
{
absoluteTime = 0;
}
chunkHeader = Encoding.UTF8.GetString(br.ReadBytes(4));
if (chunkHeader != "MTrk")
{
throw new FormatException("Invalid chunk header");
}
chunkSize = SwapUInt32(br.ReadUInt32());
long startPos = br.BaseStream.Position;
MidiEvent me = null;
var outstandingNoteOns = new List <NoteOnEvent>();
while (br.BaseStream.Position < startPos + chunkSize)
{
me = MidiEvent.ReadNextEvent(br, me);
absoluteTime += me.DeltaTime;
me.AbsoluteTime = absoluteTime;
events[track].Add(me);
if (me.CommandCode == MidiCommandCode.NoteOn)
{
NoteEvent ne = (NoteEvent)me;
if (ne.Velocity > 0)
{
outstandingNoteOns.Add((NoteOnEvent)ne);
}
else
{
// don't remove the note offs, even though
// they are annoying
// events[track].Remove(me);
FindNoteOn(ne, outstandingNoteOns);
}
}
else if (me.CommandCode == MidiCommandCode.NoteOff)
{
FindNoteOn((NoteEvent)me, outstandingNoteOns);
}
else if (me.CommandCode == MidiCommandCode.MetaEvent)
{
MetaEvent metaEvent = (MetaEvent)me;
if (metaEvent.MetaEventType == MetaEventType.EndTrack)
{
//break;
// some dodgy MIDI files have an event after end track
if (strictChecking)
{
if (br.BaseStream.Position < startPos + chunkSize)
{
throw new FormatException(String.Format("End Track event was not the last MIDI event on track {0}", track));
}
}
}
}
}
if (outstandingNoteOns.Count > 0)
{
if (strictChecking)
{
throw new FormatException(String.Format("Note ons without note offs {0} (file format {1})", outstandingNoteOns.Count, fileFormat));
}
}
if (br.BaseStream.Position != startPos + chunkSize)
{
throw new FormatException(String.Format("Read too far {0}+{1}!={2}", chunkSize, startPos, br.BaseStream.Position));
}
}
}
}
