public static MIDIData readFile(string filePath)
{
MIDIData data = new MIDIData();
try
{
Console.WriteLine("Reading file {0}", filePath);
byte[] fileBytes = File.ReadAllBytes(filePath);
UInt64 trackChunkStart = MIDIFileReader.readHeader(fileBytes, data);
Console.WriteLine("format: {0}, ntracks: {1}, tickdiv: {2} ", data.format, data.ntracks, data.tickdiv);
if (data.timing == TimingScheme.MetricalTiming)
{
Console.WriteLine("Metrical timing PPQN: {0}", data.metrical_ppqn);
}
else
{
Console.WriteLine("Timecode FPS: {0} SFR:{1}", data.timecode_fps, data.timecode_sfr);
}
UInt64 trackChunkEnd = trackChunkStart;
while (trackChunkEnd < (UInt64)fileBytes.Length && data.tracks.Count < data.ntracks)
{
trackChunkEnd = MIDIFileReader.readTracks(fileBytes, data, trackChunkEnd);
Console.WriteLine("Track {0} read with {1} events", data.tracks.Count, data.tracks[data.tracks.Count - 1].events.Count);
}
}
catch (Exception e)
{
Console.WriteLine("Failed to read file {0}: {1}\n{2}", filePath, e.Message, e.StackTrace);
}
return(data);
}
static UInt64 readTracks(byte[] fileData, MIDIData data, UInt64 chunkStart)
{
UInt64 index = chunkStart;
while (index < (UInt64)fileData.Length)
{
// start reading a track chunk
if ((UInt64)fileData.Length < index + 8)
{
throw new Exception("File data too short to contain track chunk at index " + index);
}
if (!(fileData[index + 0] == 0x4d && fileData[index + 1] == 0x54 && fileData[index + 2] == 0x72 && fileData[index + 3] == 0x6B)) // "MTrk"
{
throw new Exception("File data does not contain expected track identifier at index " + index);
}
index += 4;
ushort chunklen = 0;
chunklen |= (ushort)((ushort)fileData[index + 0] << 24);
chunklen |= (ushort)((ushort)fileData[index + 1] << 16);
chunklen |= (ushort)((ushort)fileData[index + 2] << 8);
chunklen |= (ushort)((ushort)fileData[index + 3]);
index += 4;
Console.WriteLine("Chunklen {0}", chunklen);
if ((UInt64)fileData.Length < index + chunklen)
{
throw new Exception("File data too short to contain track chunk of length " + chunklen + " at index " + (index - 8));
}
MIDITrack track = new MIDITrack();
UInt64 trackindex = index;
MIDIEvent previous = new MIDIEvent();
while (trackindex < index + chunklen)
{
MIDIEvent new_event = MIDIFileReader.readEvent(fileData, ref trackindex, previous);
previous = new_event;
track.events.Add(new_event);
}
data.tracks.Add(track);
index = trackindex;
break;
}
return(index);
}
// reads event or throws exception, advances index to end of event fields
// In a breathtaking display of parsimony, instructions that repeat the status
// byte of the previous instruction *may be* written without that status byte.
// If there isn't a high-bit byte following the delta-time, assume it's a repeated
// instruction. The transmission speeds of early equipment must have been
// extremely low.
public static MIDIEvent readEvent(byte[] fileData, ref UInt64 index, MIDIEvent previous)
{
MIDIEvent new_event = new MIDIEvent();
UInt64 trackindex = index;
new_event.delta = readVariableLengthQuantity(fileData, ref trackindex);
new_event.pos = index;
switch (fileData[trackindex] >> 4 & 0xF) // first 4 bits
{
case 0x8:
new_event.type = EventType.MIDIEvent;
new_event.midieventtype = MIDIEventType.NoteOff;
new_event.val1 = (uint)(fileData[trackindex] & 0x7); // channel
new_event.val2 = (uint)(fileData[trackindex + 1]); // key number
new_event.val3 = (uint)(fileData[trackindex + 2]); // velocity
trackindex += 3;
break;
case 0x9:
new_event.type = EventType.MIDIEvent;
new_event.midieventtype = MIDIEventType.NoteOn;
new_event.val1 = (uint)(fileData[trackindex] & 0x7); // channel
new_event.val2 = (uint)(fileData[trackindex + 1]); // key number
new_event.val3 = (uint)(fileData[trackindex + 2]); // velocity
trackindex += 3;
break;
case 0xA:
new_event.type = EventType.MIDIEvent;
new_event.midieventtype = MIDIEventType.NoteOn;
new_event.val1 = (uint)(fileData[trackindex] & 0x7); // channel
new_event.val2 = (uint)(fileData[trackindex + 1]); // key number
new_event.val3 = (uint)(fileData[trackindex + 2]); // velocity
trackindex += 3;
break;
case 0xB:
new_event.type = EventType.MIDIEvent;
new_event.midieventtype = MIDIEventType.Controller;
new_event.val1 = (uint)(fileData[trackindex] & 0x7); // channel
new_event.val2 = (uint)(fileData[trackindex + 1]); // controller
new_event.val3 = (uint)(fileData[trackindex + 2]); // value
trackindex += 3;
break;
case 0xC:
new_event.type = EventType.MIDIEvent;
new_event.midieventtype = MIDIEventType.ProgramChange;
new_event.val1 = (uint)(fileData[trackindex] & 0x7); // channel
new_event.val2 = (uint)(fileData[trackindex + 1]); // program
trackindex += 2;
break;
case 0xD:
new_event.type = EventType.MIDIEvent;
new_event.midieventtype = MIDIEventType.ChannelPresure;
new_event.val1 = (uint)(fileData[trackindex] & 0x7); // channel
new_event.val2 = (uint)(fileData[trackindex + 1]); // pressure
trackindex += 2;
break;
case 0xE:
new_event.type = EventType.MIDIEvent;
new_event.midieventtype = MIDIEventType.PitchBend;
new_event.val1 = (uint)(fileData[trackindex] & 0x7); // channel
new_event.val2 = (uint)(fileData[trackindex + 1]); // lsb
new_event.val3 = (uint)(fileData[trackindex + 2]); // msb
trackindex += 3;
break;
case 0xF:
if ((fileData[trackindex] & 0xF) == 0xF) // Meta event
{
new_event.type = EventType.MetaEvent;
ushort type = (ushort)fileData[trackindex + 1];
trackindex = trackindex + 2;
uint length = MIDIFileReader.readVariableLengthQuantity(fileData, ref trackindex); // trackindex updated to end of length field
if (trackindex + length > (UInt64)fileData.Length)
{
throw new Exception("File data too short to contain metadata event of length " + length + " at index " + (trackindex));
}
switch (type)
{
case 0x00:
new_event.metaeventtype = MetaEventType.SequenceNumber;
if (length != 2)
{
throw new Exception("Metadata sequence number event with incorrect length " + length + " (should be 2) found at index " + (trackindex));
}
new_event.val1 = (ushort)((fileData[trackindex] << 8) | fileData[trackindex + 1]);
break;
case 0x01:
new_event.metaeventtype = MetaEventType.Text;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x02:
new_event.metaeventtype = MetaEventType.Copyright;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x03:
new_event.metaeventtype = MetaEventType.SequenceTrackName;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x04:
new_event.metaeventtype = MetaEventType.InstrumentName;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x05:
new_event.metaeventtype = MetaEventType.Lyric;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x06:
new_event.metaeventtype = MetaEventType.Marker;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x07:
new_event.metaeventtype = MetaEventType.CuePoint;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x08:
new_event.metaeventtype = MetaEventType.ProgramName;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x09:
new_event.metaeventtype = MetaEventType.DeviceName;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
case 0x20:
new_event.metaeventtype = MetaEventType.MIDIChannelPrefix;
if (length != 0x01)
{
throw new Exception("Metadata MIDI channel prefix event with incorrect length " + length + " (should be 1) found at index " + (trackindex));
}
new_event.val1 = fileData[trackindex];
break;
case 0x21:
new_event.metaeventtype = MetaEventType.MIDIPort;
if (length != 0x01)
{
throw new Exception("Metadata MIDI port event with incorrect length " + length + " (should be 1) found at index " + (trackindex));
}
new_event.val1 = fileData[trackindex];
break;
case 0x2F:
new_event.metaeventtype = MetaEventType.EndOfTrack;
if (length != 0)
{
throw new Exception("Metadata end of track event with incorrect length " + length + " (should be 0) found at index " + (trackindex));
}
break;
case 0x51:
new_event.metaeventtype = MetaEventType.Tempo;
if (length != 0x03)
{
throw new Exception("Metadata tempo event with incorrect length " + length + " (should be 3) found at index " + (trackindex));
}
new_event.val1 = (uint)(fileData[trackindex] << 16 | fileData[trackindex + 1] << 8 | fileData[trackindex + 2]);
break;
case 0x54:
new_event.metaeventtype = MetaEventType.SMPTEOffset;
if (length != 0x05)
{
throw new Exception("Metadata SMPTE offset event with incorrect length " + length + " (should be 5) found at index " + (trackindex));
}
new_event.val1 = (uint)(fileData[trackindex]);
new_event.val2 = (uint)(fileData[trackindex + 1]);
new_event.val3 = (uint)(fileData[trackindex + 2]);
new_event.val4 = (uint)(fileData[trackindex + 3]);
new_event.val5 = (uint)(fileData[trackindex + 4]);
break;
case 0x58:
new_event.metaeventtype = MetaEventType.TimeSignature;
if (length != 0x04)
{
throw new Exception("Metadata time signature event with incorrect length " + length + " (should be 4) found at index " + (trackindex));
}
new_event.val1 = (uint)(fileData[trackindex]);
new_event.val2 = (uint)(fileData[trackindex + 1]);
new_event.val3 = (uint)(fileData[trackindex + 2]);
new_event.val4 = (uint)(fileData[trackindex + 3]);
break;
case 0x59:
new_event.metaeventtype = MetaEventType.KeySignature;
if (length != 0x02)
{
throw new Exception("Metadata key signature event with incorrect length " + length + " (should be 2) found at index " + (trackindex));
}
new_event.val1 = (uint)(fileData[trackindex]);
new_event.val2 = (uint)(fileData[trackindex + 1]);
break;
case 0x7F:
new_event.metaeventtype = MetaEventType.SequencerSpecificEvent;
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
break;
default:
throw new Exception("Unknown metadata field type " + type + " found at index " + (trackindex));
break;
}
trackindex += length;
}
else // SysEx event (or error)
{
if (fileData[trackindex] == 0xF0)
{
new_event.type = EventType.SysExEvent;
trackindex += 2;
UInt64 temp = trackindex - 1;
uint length = MIDIFileReader.readVariableLengthQuantity(fileData, ref trackindex); // trackindex updated to end of length field
new_event.message = MIDIFileReader.readEventMessage(fileData, trackindex, length);
if (new_event.message[new_event.message.Count - 1] == 0xF7)
{
new_event.sysexeeventtype = SysExEventType.SingleEvent;
}
if (new_event.message[new_event.message.Count - 1] == 0x00)
{
new_event.sysexeeventtype = SysExEventType.ContinuationEvent;
uint delta_time = MIDIFileReader.readVariableLengthQuantity(fileData, ref trackindex);
}
}
else
{
// hope that this is only two bytes long
Console.WriteLine("Unknown event at index {0} with opening byte {1:X2}", trackindex, fileData[trackindex]);
new_event.type = EventType.UnknownEvent;
new_event.val1 = fileData[trackindex]; //fileData[trackindex + 1];
new_event.val2 = fileData[trackindex + 1];
trackindex += 2;
//throw new Exception(String.Format("Unknown field found {0:X2} at index {1}", fileData[trackindex], trackindex));
}
}
break;
default:
// okay, might be a running status. Check the provided previous event, which must be a MIDI event rather than a sysex or meta event
if (previous.type != EventType.MIDIEvent)
{
throw new Exception(String.Format("Undefined event start {0:X2} byte at index {1} ", fileData[trackindex], trackindex));
}
switch (previous.midieventtype)
{
case MIDIEventType.NoteOff:
new_event.midieventtype = previous.midieventtype;
new_event.val1 = previous.val1;
new_event.val2 = fileData[trackindex];
new_event.val3 = fileData[trackindex + 1];
trackindex += 2;
new_event.running = true;
break;
case MIDIEventType.NoteOn:
new_event.midieventtype = previous.midieventtype;
new_event.val1 = previous.val1;
new_event.val2 = fileData[trackindex];
new_event.val3 = fileData[trackindex + 1];
trackindex += 2;
new_event.running = true;
break;
case MIDIEventType.PolyphonicPressure:
new_event.midieventtype = previous.midieventtype;
new_event.val1 = previous.val1;
new_event.val2 = fileData[trackindex];
new_event.val3 = fileData[trackindex + 1];
trackindex += 2;
new_event.running = true;
break;
case MIDIEventType.Controller:
new_event.midieventtype = previous.midieventtype;
new_event.val1 = previous.val1;
new_event.val2 = fileData[trackindex];
new_event.val3 = fileData[trackindex + 1];
trackindex += 2;
new_event.running = true;
break;
case MIDIEventType.ProgramChange:
new_event.midieventtype = previous.midieventtype;
new_event.val1 = previous.val1;
new_event.val2 = fileData[trackindex];
trackindex += 1;
new_event.running = true;
break;
case MIDIEventType.ChannelPresure:
new_event.midieventtype = previous.midieventtype;
new_event.val1 = previous.val1;
new_event.val2 = fileData[trackindex];
trackindex += 1;
new_event.running = true;
break;
case MIDIEventType.PitchBend:
new_event.midieventtype = previous.midieventtype;
new_event.val1 = previous.val1;
new_event.val2 = fileData[trackindex];
new_event.val3 = fileData[trackindex + 1];
trackindex += 2;
new_event.running = true;
break;
default:
throw new Exception(String.Format("Undefined event start {0:X2} byte at index {1} ", fileData[trackindex], trackindex));
break;
}
break;
}
index = trackindex;
return(new_event);
}
