/// <summary>
/// Reads a meta-event from a stream
/// </summary>
/// <param name="br">A binary reader based on the stream of MIDI data</param>
/// <returns>A new MetaEvent object</returns>
public static MetaEvent ReadMetaEvent(BinaryReader br)
{
MetaEventType metaEvent = (MetaEventType) br.ReadByte();
int length = ReadVarInt(br);
MetaEvent me = new MetaEvent();
switch(metaEvent)
{
case MetaEventType.TrackSequenceNumber: // Sets the track's sequence number.
me = new TrackSequenceNumberEvent(br,length);
break;
case MetaEventType.TextEvent: // Text event
case MetaEventType.Copyright: // Copyright
case MetaEventType.SequenceTrackName: // Sequence / Track Name
case MetaEventType.TrackInstrumentName: // Track instrument name
case MetaEventType.Lyric: // lyric
case MetaEventType.Marker: // marker
case MetaEventType.CuePoint: // cue point
case MetaEventType.ProgramName:
case MetaEventType.DeviceName:
me = new TextEvent(br,length);
break;
case MetaEventType.EndTrack: // This event must come at the end of each track
if(length != 0)
{
throw new FormatException("End track length");
}
break;
case MetaEventType.SetTempo: // Set tempo
me = new TempoEvent(br,length);
break;
case MetaEventType.TimeSignature: // Time signature
me = new TimeSignatureEvent(br,length);
break;
case MetaEventType.KeySignature: // Key signature
me = new KeySignatureEvent(br, length);
break;
case MetaEventType.SequencerSpecific: // Sequencer specific information
me = new SequencerSpecificEvent(br, length);
break;
case MetaEventType.SmpteOffset:
me = new SmpteOffsetEvent(br, length);
break;
default:
//System.Windows.Forms.MessageBox.Show(String.Format("Unsupported MetaEvent {0} length {1} pos {2}",metaEvent,length,br.BaseStream.Position));
me.data = br.ReadBytes(length);
if (me.data.Length != length)
{
throw new FormatException("Failed to read metaevent's data fully");
}
break;
}
me.metaEvent = metaEvent;
me.metaDataLength = length;
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>
/// Compares two MidiEvents
/// Sorts by time, with EndTrack always sorted to the end
/// </summary>
public int Compare(MidiEvent x, MidiEvent y)
{
long xTime = x.AbsoluteTime;
long yTime = y.AbsoluteTime;
if (xTime == yTime)
{
// sort meta events before note events, except end track
MetaEvent xMeta = x as MetaEvent;
MetaEvent yMeta = y as MetaEvent;
if (xMeta != null)
{
if (xMeta.MetaEventType == MetaEventType.EndTrack)
{
xTime = Int64.MaxValue;
}
else
{
xTime = Int64.MinValue;
}
}
if (yMeta != null)
{
if (yMeta.MetaEventType == MetaEventType.EndTrack)
{
yTime = Int64.MaxValue;
}
else
{
yTime = Int64.MinValue;
}
}
}
return(xTime.CompareTo(yTime));
}
/// <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>
/// Reads a meta-event from a stream
/// </summary>
/// <param name="br">A binary reader based on the stream of MIDI data</param>
/// <returns>A new MetaEvent object</returns>
public static MetaEvent ReadMetaEvent(BinaryReader br)
{
MetaEventType metaEvent = (MetaEventType)br.ReadByte();
int length = ReadVarInt(br);
MetaEvent me = new MetaEvent();
switch (metaEvent)
{
case MetaEventType.TrackSequenceNumber: // Sets the track's sequence number.
me = new TrackSequenceNumberEvent(br, length);
break;
case MetaEventType.TextEvent: // Text event
case MetaEventType.Copyright: // Copyright
case MetaEventType.SequenceTrackName: // Sequence / Track Name
case MetaEventType.TrackInstrumentName: // Track instrument name
case MetaEventType.Lyric: // lyric
case MetaEventType.Marker: // marker
case MetaEventType.CuePoint: // cue point
case MetaEventType.ProgramName:
case MetaEventType.DeviceName:
me = new TextEvent(br, length);
break;
case MetaEventType.EndTrack: // This event must come at the end of each track
if (length != 0)
{
throw new FormatException("End track length");
}
break;
case MetaEventType.SetTempo: // Set tempo
me = new TempoEvent(br, length);
break;
case MetaEventType.TimeSignature: // Time signature
me = new TimeSignatureEvent(br, length);
break;
case MetaEventType.KeySignature: // Key signature
me = new KeySignatureEvent(br, length);
break;
case MetaEventType.SequencerSpecific: // Sequencer specific information
me = new SequencerSpecificEvent(br, length);
break;
case MetaEventType.SmpteOffset:
me = new SmpteOffsetEvent(br, length);
break;
default:
//System.Windows.Forms.MessageBox.Show(String.Format("Unsupported MetaEvent {0} length {1} pos {2}",metaEvent,length,br.BaseStream.Position));
me.data = br.ReadBytes(length);
if (me.data.Length != length)
{
throw new FormatException("Failed to read metaevent's data fully");
}
break;
}
me.metaEvent = metaEvent;
me.metaDataLength = length;
return(me);
}
/// <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));
}
}
}
}
