// chunk = <chunk_id> + <chunk_length> + <chunk_bytes>
public Chunk(Stream stream)
{
Id = StreamHelperBe.ReadString(stream, 4);
Length = (int)StreamHelperBe.ReadUInt32(stream);
// DebugConsole.WriteLine("Padding " + (Length & 1));
Bytes = new byte[Length];
stream.Read(Bytes, 0, Length);
}
public MidiFile(Stream stream)
{
// header_chunk = "MThd" + <header_length> + <format> + <n> + <division>
var chunk = new Chunk(stream);
if (chunk.Id != "MThd")
{
throw new FileFormatException("MidiFile.chunk.Id", chunk.Id, "MThd");
}
using (var header = chunk.GetStream()) {
Format = (MidiFileFormat)StreamHelperBe.ReadInt16(header);
NumberOfTracks = StreamHelperBe.ReadUInt16(header);
var division = StreamHelperBe.ReadInt16(header);
if (division > 0)
{
TicksPerBeat = division;
}
else
{
throw new Exception("STMPE based time is not supported");
}
}
// track_chunk = "MTrk" + <track_length> [+ <delta_time> + <event> ...]
for (int track = 0; track < NumberOfTracks; track++)
{
chunk = new Chunk(stream);
if (chunk.Id != "MTrk")
{
throw new FileFormatException("MidiFile.chunk.Id", chunk.Id, "MTrk");
}
using (var trackStream = chunk.GetStream()) {
BuildTrack(trackStream, track);
}
}
Sort();
Rebase();
Trim();
}
void BuildTrack(Stream stream, int track)
{
int tick = 0;
byte runningStatus = 0x00;
while (stream.Position < stream.Length)
{
tick += (int)StreamHelperBe.ReadVlv(stream);
var statusByte = (byte)stream.ReadByte();
if (statusByte < 0xF0) // Midi events (status bytes 0x8n - 0xEn)
{
byte dataByte1;
if (statusByte < 0x80) // If the first byte < 0x80, running status is in effect, and this byte is actually the first data byte.
{
dataByte1 = statusByte;
statusByte = runningStatus;
}
else
{
dataByte1 = (byte)stream.ReadByte();
runningStatus = statusByte;
}
var midiEvent = new MidiEvent(track, tick, statusByte);
switch (statusByte & 0xF0)
{
case 0x80: // Note Off
case 0x90: // Note On
case 0xA0: // Aftertouch
case 0xB0: // Controller Change
case 0xE0: // Pitch Bend
midiEvent.DataByte1 = dataByte1;
midiEvent.DataByte2 = (byte)stream.ReadByte();
break;
case 0xC0: // Program Change
case 0xD0: // Channel Aftertouch
midiEvent.DataByte1 = dataByte1;
break;
default:
throw new FileFormatException("MidiFile.statusByte", statusByte.ToString("X"), "[midi statusByte]");
}
if (midiEvent.Type == MidiEventType.NoteOn && midiEvent.Velocity == 0)
{
midiEvent.StatusByte = (byte)(0x80 | midiEvent.Channel);
}
MidiEvents.Add(midiEvent);
}
else if (statusByte == 0xF0 || statusByte == 0xF7) // SysEx events (status bytes 0xF0 and 0xF7)
{
runningStatus = 0x00;
var sysExEvent =
new SysExEvent(track, tick, (int)StreamHelperBe.ReadVlv(stream));
stream.Read(sysExEvent.Bytes, 0, sysExEvent.Length);
SysExEvents.Add(sysExEvent);
}
else if (statusByte == 0xFF) // Meta events (status byte 0xFF)
{
runningStatus = 0x00;
var metaEvent =
new MetaEvent(track, tick, (byte)stream.ReadByte(), (int)StreamHelperBe.ReadVlv(stream));
stream.Read(metaEvent.Data, 0, metaEvent.Length);
MetaEvents.Add(metaEvent);
}
else
{
throw new FileFormatException("MidiFile.statusByte", statusByte.ToString("X"), "[midi statusByte]");
}
}
Length = Math.Max(Length, tick);
}
