static MidiTrack ReadTrack(MidiDataStreamReader reader)
{
var track = new MidiTrack();
// Chunk type.
if (new string (reader.ReadChars(4)) != "MTrk")
{
throw new System.FormatException("Can't find track chunk.");
}
// Chunk length.
var chunkEnd = reader.ReadBEInt32();
chunkEnd += reader.Offset;
// Read delta-time and event pairs.
byte ev = 0;
while (reader.Offset < chunkEnd)
{
// Delta time.
var delta = reader.ReadMultiByteValue();
// Event type.
if ((reader.PeekByte() & 0x80) != 0)
{
ev = reader.ReadByte();
}
if (ev == 0xff)
{
// 0xff: Meta event (unused).
reader.Advance(1);
reader.Advance(reader.ReadMultiByteValue());
}
else if (ev == 0xf0)
{
// 0xf0: SysEx (unused).
while (reader.ReadByte() != 0xf7)
{
}
}
else
{
// MIDI event
byte data1 = reader.ReadByte();
byte data2 = ((ev & 0xe0) == 0xc0) ? (byte)0 : reader.ReadByte();
track.AddEvent(delta, new MidiEvent(ev, data1, data2));
}
}
return(track);
}
public static MidiFileContainer Load(byte[] data)
{
var tracks = new List <MidiTrack> ();
var reader = new MidiDataStreamReader(data);
// Chunk type.
if (new string (reader.ReadChars(4)) != "MThd")
{
throw new System.FormatException("Can't find header chunk.");
}
// Chunk length.
if (reader.ReadBEInt32() != 6)
{
throw new System.FormatException("Length of header chunk must be 6.");
}
// Format (unused).
reader.Advance(2);
// Number of tracks.
var trackCount = reader.ReadBEInt16();
// Delta-time divisions.
var division = reader.ReadBEInt16();
if ((division & 0x8000) != 0)
{
throw new System.FormatException("SMPTE time code is not supported.");
}
// Read the tracks.
for (var trackIndex = 0; trackIndex < trackCount; trackIndex++)
{
tracks.Add(ReadTrack(reader));
}
return(new MidiFileContainer(division, tracks));
}