/// <summary>
/// Exports a MIDI file
/// </summary>
/// <param name="filename">Filename to export to</param>
/// <param name="events">Events to export</param>
public static void Export(string filename, MidiEventCollection events)
{
#if UNITY_STANDALONE_OSX || UNITY_STANDALONE_WIN
if (events.MidiFileType == 0 && events.Tracks > 1)
{
throw new ArgumentException("Can't export more than one track to a type 0 file");
}
using (var writer = new BinaryWriter(File.Create(filename)))
{
writer.Write(Encoding.UTF8.GetBytes("MThd"));
writer.Write(SwapUInt32((uint)6)); // chunk size
writer.Write(SwapUInt16((ushort)events.MidiFileType));
writer.Write(SwapUInt16((ushort)events.Tracks));
writer.Write(SwapUInt16((ushort)events.DeltaTicksPerQuarterNote));
for (int track = 0; track < events.Tracks; track++)
{
IList <MidiEvent> eventList = events[track];
writer.Write(Encoding.UTF8.GetBytes("MTrk"));
long trackSizePosition = writer.BaseStream.Position;
writer.Write(SwapUInt32((uint)0));
long absoluteTime = events.StartAbsoluteTime;
// use a stable sort to preserve ordering of MIDI events whose
// absolute times are the same
MergeSort.Sort(eventList, new MidiEventComparer());
if (eventList.Count > 0)
{
System.Diagnostics.Debug.Assert(MidiEvent.IsEndTrack(eventList[eventList.Count - 1]), "Exporting a track with a missing end track");
}
foreach (MidiEvent midiEvent in eventList)
{
midiEvent.Export(ref absoluteTime, writer);
}
uint trackChunkLength = (uint)(writer.BaseStream.Position - trackSizePosition) - 4;
writer.BaseStream.Position = trackSizePosition;
writer.Write(SwapUInt32(trackChunkLength));
writer.BaseStream.Position += trackChunkLength;
}
}
#endif
}
