add midi2csv.py and csv2wav.py

csv2wav.py

@@ -0,0 +1,96 @@
+#!/usr/bin/env python
+import argparse
+import csv
+from math import pi, sin
+import sys
+import wave
+
+parser = argparse.ArgumentParser()
+parser.add_argument("input", help="input CSV (pitch, duration, pause)")
+parser.add_argument("-o", "--output", default="/dev/stdout", help="output file (wav)")
+parser.add_argument("--framerate", default=48000, type=int, help="framerate")
+parser.add_argument("--bpm", default=60, type=float, help="beats per minute")
+args = parser.parse_args()
+
+# starting from C3 = 130.81 Hz
+octave = ["c", "c#", "d", "d#", "e", "f", "f#", "g", "g#", "a", "a#", "b"]
+frequencies = {
+    f"{octave[i % 12]}{i // 12 + 3}": 2 ** (i / 12) * 130.81 for i in range(36)
+}
+# duration of 1/16th beat
+base_duration = 60 / args.bpm / 16
+
+with wave.open(args.output, "wb") as wav:
+    wav.setnchannels(1)
+    wav.setsampwidth(1)
+    wav.setframerate(args.framerate)
+    with open(args.input, "r") as notes:
+        for pitch, duration, pause in csv.reader(notes):
+            if pitch == "":
+                # skip comment
+                continue
+            try:
+                frequency = frequencies[pitch]
+            except KeyError:
+                sys.exit("pitch goes from c3 to b5")
+            duration = int(duration)
+            pause = int(pause)
+            if duration < 1 or pause < -1:
+                sys.exit("duration/pause are integer multiples of 1/16th beat")
+            attack_samples = int(0.1 * args.framerate)
+            duration_samples = int(
+                max(0, duration * base_duration - 0.2) * args.framerate
+            )
+            wav.writeframes(
+                bytes(
+                    [
+                        int(
+                            127
+                            * i
+                            * sin(2 * pi * frequency * i / args.framerate)
+                            / attack_samples
+                        ) % 256
+                        for i in range(attack_samples)
+                    ]
+                )
+            )
+            wav.writeframes(
+                bytes(
+                    [
+                        int(
+                            127
+                            * sin(
+                                2
+                                * pi
+                                * frequency
+                                * (i + attack_samples)
+                                / args.framerate
+                            )
+                        ) % 256
+                        for i in range(duration_samples)
+                    ]
+                )
+            )
+            wav.writeframes(
+                bytes(
+                    [
+                        int(
+                            127
+                            * (attack_samples - i)
+                            * sin(
+                                2
+                                * pi
+                                * frequency
+                                * (i + attack_samples + duration_samples)
+                                / args.framerate
+                            )
+                            / attack_samples
+                        ) % 256
+                        for i in range(attack_samples)
+                    ]
+                )
+            )
+            if pause != -1:
+                wav.writeframes(
+                    bytes([0] * int(pause * base_duration * args.framerate))
+                )

midi2csv.py

@@ -0,0 +1,45 @@
+#!/usr/bin/env python
+import argparse
+import csv
+import mido
+import sys
+
+parser = argparse.ArgumentParser()
+parser.add_argument("input", help="input file (midi)")
+parser.add_argument(
+    "-o", "--output", default="/dev/stdout", help="output CSV (pitch, duration, pause)"
+)
+parser.add_argument("-t", "--track", default=0, type=int, help="track number")
+parser.add_argument("-c", "--channel", default=0, type=int, help="channel number")
+args = parser.parse_args()
+
+octave = ["c", "c#", "d", "d#", "e", "f", "f#", "g", "g#", "a", "a#", "b"]
+pitches = [f"{octave[i % 12]}{i // 12 + 3}" for i in range(36)]
+
+midifile = mido.MidiFile(args.input)
+time = 0
+note = 0
+time_on = 0
+time_off = 0
+with open(args.output, "w") as notes:
+    writer = csv.writer(notes)
+    for event in midifile.tracks[args.track]:
+        writer.writerow(["", "", event])
+        # convert time to 1/16th beats
+        time += event.time * 16 // midifile.ticks_per_beat
+        if event.type == "note_on" and event.channel == args.channel:
+            # if mulitple notes start at the same time, play the highest
+            if event.velocity != 0 and (time_on != time or note < event.note):
+                if time_off <= time_on:
+                    time_off = time
+                if note != 0 and time_off - time_on > 0:
+                    writer.writerow(
+                        [pitches[note - 60], time_off - time_on, time - time_off]
+                    )
+                note = event.note
+                if note - 60 < 0 or note - 60 >= len(pitches):
+                    sys.exit("note out of range c3 to b5")
+                time_on = time
+            elif note == event.note:
+                time_off = time
+    writer.writerow([pitches[note - 60], time - time_on, 0])