添加一些关于midi播放的项目

Midi/arduino-midi-player-master/smf2seq.js

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+/*
+ *	SMF to SEQ
+ *
+ *	Convert Standard MIDI file to event array
+ *	Output file as sequence.h: to be compiled with ino files
+ *
+ *	This program uses part of jasmid to decode and parse .mid files
+ *	Please refer to jasmid/LICENSE for the jasmid license
+ *
+ *	Run this file with node.js
+ *	$ node smf2seq.js [SMF filename]
+ *
+ *	2016 by ilufang
+ */
+
+Midifile = require("./jasmid/midifile.js");
+fs = require("fs");
+
+// # Read and parse SMF
+var filename = process.argv[2]?process.argv[2]:"song.mid";
+var midi_blob = fs.readFileSync(filename);
+var t = "";
+for (var i=0; i<midi_blob.length; i++) {
+	t += String.fromCharCode(midi_blob[i] & 255);
+}
+try {
+	midi = Midifile(t);
+} catch(e) {
+	console.error("Could not parse midi.");
+	process.exit(1);
+}
+
+if (midi.header.formatType != 1) {
+	console.error("MIDI Type not supported. Expect 1, got "+midi.header.formatType);
+	process.exit(1);
+}
+
+// fs.writeFileSync("midi.json",JSON.stringify(midi,null,'\t'));
+// process.exit();
+
+// # Process events
+
+var ptr = []; // iteration pointer per track
+seq = []; // merged result
+
+// convert delta time to accumulative time
+for (var t in midi.tracks) {
+	ptr.push(0); // Irrelevant to the calculation, just initialize ptr
+
+	var tick = 0;
+	var width = 0, maxwidth = 0;
+	for (var i in midi.tracks[t]) {
+		tick += midi.tracks[t][i].deltaTime;
+		midi.tracks[t][i].time = tick;
+		midi.tracks[t][i].track = parseInt(t); // Still need to keep track of the track
+	}
+}
+
+// Merge the tracks
+var time = 0;
+while(true) {
+	// 'Pop' front
+	var minTrack = 0;
+	for (var t in midi.tracks) {
+		if (!midi.tracks[t][ptr[t]]) {
+			if (minTrack == t) {
+				// In case a prior tracks are shorter, assign the default minTrack to a latter one
+				minTrack++;
+			}
+			continue;
+		}
+		if (midi.tracks[t][ptr[t]].time < midi.tracks[minTrack][ptr[minTrack]].time) { minTrack = t; }
+	}
+	if (minTrack==midi.tracks.length) {
+		// No tracks have events left
+		break;
+	}
+	seq.push(midi.tracks[minTrack][ptr[minTrack]]);
+	ptr[minTrack]++;
+}
+
+// Scan for consecutive notes
+/*
+time = 0;
+var notes_off = {};
+for (var i = 0; i < seq.length; i++) {
+	if (seq[i].time != time) {
+		time = seq[i].time;
+		notes_off = {};
+	}
+	if (seq[i].type=="channel") {
+		if (seq[i].subtype=="noteOff") {
+			notes_off[seq[i].noteNumber] = i;
+		} else if (seq[i].subtype=="noteOn") {
+			if (notes_off[seq[i].noteNumber]) {
+				seq[notes_off[seq[i].noteNumber]].time -= 20;
+			}
+		}
+	}
+}
+*/
+
+// Regenerate deltatime
+var tempo = 0;
+
+var notes = [], note_params = [];
+
+for (var i=0; i<seq.length; i++) {
+	if (seq[i+1]) {
+		seq[i].deltaTime = seq[i+1].time - seq[i].time;
+	} else {
+		seq[i].deltatime = 0;
+	}
+	prevTime = seq[i].time;
+
+	if (seq[i].type=="meta" && seq[i].subtype =="setTempo") {
+		tempo = 1.0*seq[i].microsecondsPerBeat/1000/midi.header.ticksPerBeat;
+	} else if (seq[i].type=="channel") {
+		if (seq[i].subtype=="noteOff") {
+			seq[i].velocity = 0;
+		}
+		if (seq[i].subtype=="noteOn" || seq[i].subtype=="noteOff") {
+			seq[i].velocity*=128/96;
+			if (seq[i].velocity > 127)
+				seq[i].velocity = 127;
+			notes.push(seq[i].noteNumber);
+			note_params.push((seq[i].deltaTime<<4)+(seq[i].velocity>>3));
+		}
+	}
+}
+
+fs.writeFileSync("midi.json", JSON.stringify(seq, null, '\t'));
+
+// # Generate sin table
+var file = "// MIDI events\n// Generated by smf2seq.js\n";
+
+var sine_sample = [], sine_sample_size = 256;
+for (var i = 0; i < sine_sample_size; i++) {
+	sine_sample.push(128+Math.round(128*Math.sin(2*Math.PI*i/sine_sample_size)));
+}
+
+file += "const unsigned char sine[] = {"+sine_sample.join(",")+"};\n";
+file += "#define TEMPO "+tempo+"\n";
+file += "#define SONG_LEN "+notes.length+"\n";
+file += "PROGMEM const unsigned char notes[] = {"+notes.join(",")+"};\n";
+file += "PROGMEM const int params[] = {"+note_params.join(",")+"};\n";
+
+console.log("Using memory: "+(notes.length*3));
+console.log("Total memory: 32256");
+
+// # Write to file
+fs.writeFileSync("sequence.h",file);