MIDI

Following Section 1.2.1 of [Müller, FMP, Springer 2015], we look in this notebook at a symbolic music representation called MIDI.

import os

import matplotlib
from matplotlib import pyplot as plt
import pretty_midi
import pandas as pd
import IPython.display as ipd

fn = 'FMP_C1_F10_Beethoven_Fifth-MM1-20_MIDI-Orchestra.mid'

Processing and Visualization with pretty_midi

# generating a table of all notes

midi_data = pretty_midi.PrettyMIDI(fn)
midi_list = []

for instrument in midi_data.instruments:
    instrument_name = instrument.name
    for note in instrument.notes:
        start = note.start
        end = note.end
        pitch = note.pitch
        velocity = note.velocity
        midi_list.append([start, end, pitch, velocity, instrument_name])
        
midi_list = sorted(midi_list, key=lambda x: x[0])

df = pd.DataFrame(midi_list, columns=['Start', 'End', 'Pitch', 'Velocity', 'Instrument'])
html = df.to_html(index=False, float_format='%.2f')
ipd.HTML(html)

Start	End	Pitch	Velocity	Instrument
0.17	0.33	67	113	Klarinette in B
0.17	0.33	67	113	Violine I
0.17	0.33	67	113	Violine II
0.17	0.33	55	113	Viola
0.17	0.33	43	113	Violoncello
0.17	0.33	43	113	Kontrabass
0.33	0.50	67	113	Klarinette in B
0.33	0.50	67	113	Violine I
0.33	0.50	67	113	Violine II
0.33	0.50	55	113	Viola
0.33	0.50	43	113	Violoncello
0.33	0.50	43	113	Kontrabass
0.50	0.67	67	113	Klarinette in B
0.50	0.67	67	113	Violine I
0.50	0.67	67	113	Violine II
0.50	0.67	55	113	Viola
0.50	0.67	43	113	Violoncello
0.50	0.67	43	113	Kontrabass
0.67	1.67	63	110	Klarinette in B
0.67	1.67	63	110	Violine I
0.67	1.67	63	110	Violine II
0.67	1.67	51	111	Viola
0.67	1.67	39	115	Violoncello
0.67	1.67	39	115	Kontrabass
1.83	2.00	65	112	Klarinette in B
1.83	2.00	65	112	Violine I
1.83	2.00	65	112	Violine II
1.83	2.00	53	112	Viola
1.83	2.00	41	113	Violoncello
1.83	2.00	41	113	Kontrabass
2.00	2.17	65	112	Klarinette in B
2.00	2.17	65	112	Violine I
2.00	2.17	65	112	Violine II
2.00	2.17	53	112	Viola
2.00	2.17	41	113	Violoncello
2.00	2.17	41	113	Kontrabass
2.17	2.33	65	113	Klarinette in B
2.17	2.33	65	113	Violine I
2.17	2.33	65	113	Violine II
2.17	2.33	53	113	Viola
2.17	2.33	41	113	Violoncello
2.17	2.33	41	113	Kontrabass
2.33	4.00	62	110	Klarinette in B
2.33	4.00	62	110	Violine I
2.33	4.00	62	110	Violine II
2.33	4.00	50	112	Viola
2.33	4.00	38	115	Violoncello
2.33	4.00	38	115	Kontrabass
4.17	4.33	67	62	Violine II
4.33	4.50	67	61	Violine II
4.50	4.67	67	61	Violine II
4.67	7.33	60	65	Fagott
4.67	6.83	63	59	Violine II
4.67	7.33	60	65	Violoncello
4.83	5.00	68	61	Viola
5.00	5.17	68	61	Viola
5.17	5.33	68	61	Viola
5.33	7.00	67	63	Viola
5.50	5.67	75	61	Violine I
5.67	5.83	75	61	Violine I
5.83	6.00	75	61	Violine I
6.00	7.00	72	60	Violine I
6.83	7.00	67	61	Violine II
7.00	7.17	67	61	Violine II
7.17	7.33	67	61	Violine II
7.33	10.00	59	65	Fagott
7.33	8.67	62	58	Violine II
7.33	10.00	59	65	Violoncello
7.50	7.67	68	61	Viola
7.67	7.83	68	61	Viola
7.83	8.00	68	61	Viola
8.00	8.67	67	63	Viola
8.17	8.33	77	61	Violine I
8.33	8.50	77	61	Violine I
8.50	8.67	77	61	Violine I
8.67	9.50	74	60	Violine I
8.67	10.17	67	66	Violine II
8.67	10.00	62	58	Viola
9.50	9.67	79	64	Violine I
9.67	9.83	79	63	Violine I
9.83	10.00	77	60	Violine I
10.00	10.67	60	65	Fagott
10.00	10.68	75	60	Violine I
10.00	10.17	63	64	Viola
10.00	10.67	60	65	Violoncello
10.17	10.33	63	60	Violine II
10.17	10.33	63	61	Viola
10.33	10.50	63	61	Violine II
10.33	10.50	63	61	Viola
10.50	10.67	65	63	Violine II
10.50	10.67	65	64	Viola
10.67	11.33	59	64	Fagott
10.67	10.82	74	61	Violine I
10.67	11.50	67	69	Violine II
10.67	11.50	67	71	Viola
10.67	11.33	59	64	Violoncello
10.83	11.00	79	65	Violine I
11.00	11.17	79	65	Violine I
11.17	11.33	77	60	Violine I
11.33	12.00	60	65	Fagott
11.33	12.01	75	59	Violine I
11.33	12.00	60	65	Violoncello
11.50	11.67	63	59	Violine II
11.50	11.67	63	59	Viola
11.67	11.83	63	60	Violine II
11.67	11.83	63	60	Viola
11.83	12.00	65	63	Violine II
11.83	12.00	65	63	Viola
12.00	12.17	59	64	Fagott
12.00	12.16	74	61	Violine I
12.00	12.17	67	70	Violine II
12.00	12.50	67	70	Viola
12.00	12.17	59	64	Violoncello
12.17	12.33	86	61	Flöte
12.17	12.33	91	61	Flöte
12.17	12.33	74	61	Oboe
12.17	12.33	79	61	Oboe
12.17	12.33	55	113	Klarinette in B
12.17	12.33	59	113	Klarinette in B
12.17	12.33	59	61	Fagott
12.17	12.33	67	61	Horn in Es
12.17	12.33	55	61	Trompete in C
12.17	12.33	67	61	Trompete in C
12.17	12.33	43	61	Pauken
12.17	12.33	79	66	Violine I
12.17	12.33	74	70	Violine II
12.17	12.33	59	61	Violoncello
12.17	12.33	35	61	Kontrabass
12.33	12.50	86	61	Flöte
12.33	12.50	91	61	Flöte
12.33	12.50	74	61	Oboe
12.33	12.50	79	61	Oboe
12.33	12.50	59	116	Klarinette in B
12.33	12.50	62	116	Klarinette in B
12.33	12.50	59	61	Fagott
12.33	12.50	67	61	Horn in Es
12.33	12.50	55	61	Trompete in C
12.33	12.50	67	61	Trompete in C
12.33	12.50	43	61	Pauken
12.33	12.50	79	65	Violine I
12.33	12.50	74	70	Violine II
12.33	12.50	59	61	Violoncello
12.33	12.50	35	61	Kontrabass
12.50	12.67	86	59	Flöte
12.50	12.67	89	59	Flöte
12.50	12.67	74	59	Oboe
12.50	12.67	77	59	Oboe
12.50	12.67	62	124	Klarinette in B
12.50	12.67	67	124	Klarinette in B
12.50	12.67	59	61	Fagott
12.50	12.67	67	61	Horn in Es
12.50	12.67	55	61	Trompete in C
12.50	12.67	67	61	Trompete in C
12.50	12.67	43	61	Pauken
12.50	12.67	77	60	Violine I
12.50	12.67	67	58	Violine II
12.50	12.67	62	61	Viola
12.50	12.67	59	61	Violoncello
12.50	12.67	35	61	Kontrabass
12.67	13.00	84	96	Flöte
12.67	13.00	87	96	Flöte
12.67	13.00	72	96	Oboe
12.67	13.00	75	96	Oboe
12.67	13.00	63	113	Klarinette in B
12.67	13.00	67	113	Klarinette in B
12.67	13.00	60	107	Fagott
12.67	13.00	67	104	Horn in Es
12.67	13.00	60	114	Trompete in C
12.67	13.00	72	114	Trompete in C
12.67	13.00	48	112	Pauken
12.67	13.00	75	95	Violine I
12.67	13.00	60	119	Violine II
12.67	13.00	67	119	Violine II
12.67	13.00	75	119	Violine II
12.67	13.00	63	104	Viola
12.67	13.00	60	107	Violoncello
12.67	13.00	36	105	Kontrabass
13.33	13.67	84	94	Flöte
13.33	13.67	72	105	Oboe
13.33	13.67	78	105	Oboe
13.33	13.67	60	107	Klarinette in B
13.33	13.67	66	107	Klarinette in B
13.33	13.67	44	91	Fagott
13.33	13.67	51	96	Horn in Es
13.33	13.67	63	96	Horn in Es
13.33	13.67	60	110	Trompete in C
13.33	13.67	72	110	Trompete in C
13.33	13.67	48	108	Pauken
13.33	13.67	56	93	Violine I
13.33	13.67	66	93	Violine I
13.33	13.67	72	93	Violine I
13.33	13.67	56	109	Violine II
13.33	13.67	66	109	Violine II
13.33	13.67	72	109	Violine II
13.33	13.67	56	91	Viola
13.33	13.67	44	91	Violoncello
13.33	13.67	32	101	Kontrabass
14.00	14.33	83	109	Flöte
14.00	14.33	91	109	Flöte
14.00	14.33	71	106	Oboe
14.00	14.33	79	106	Oboe
14.00	14.33	59	99	Klarinette in B
14.00	14.33	62	99	Klarinette in B
14.00	14.33	43	98	Fagott
14.00	14.33	55	106	Horn in Es
14.00	14.33	67	106	Horn in Es
14.00	14.33	55	99	Trompete in C
14.00	14.33	67	99	Trompete in C
14.00	14.33	43	102	Pauken
14.00	14.33	55	104	Violine I
14.00	14.33	62	104	Violine I
14.00	14.33	71	104	Violine I
14.00	14.83	79	110	Violine I
14.00	14.33	55	103	Violine II
14.00	14.33	62	103	Violine II
14.00	14.33	71	103	Violine II
14.00	14.33	55	97	Viola
14.00	14.33	43	98	Violoncello
14.00	14.33	31	102	Kontrabass

#synthesizing the MIDI data

fs = 22050
audio_data = midi_data.synthesize(fs=fs)
ipd.Audio(audio_data, rate=fs)

# plotting with velocity as "color"

plt.figure(figsize=(15, 10))
ax = plt.gca()

starts = []
ends = []
pitches = []

for instrument in midi_data.instruments:
    instrument_name = instrument.name
    for note in instrument.notes:
        start = note.start
        end = note.end
        pitch = note.pitch
        velocity = note.velocity

        rect = matplotlib.patches.Rectangle((start, pitch - 0.5), end-start, 1, linewidth=1,
                                            edgecolor='k', facecolor=str(velocity / 128), alpha=0.5)
        ax.add_patch(rect)
        
        starts.append(start)
        ends.append(end)
        pitches.append(pitch)
        
plt.ylim([min(pitches)-0.5, max(pitches) + 0.5])
plt.xlim([min(min(starts), 0), max(ends)])
plt.xlabel('Time (seconds)')
plt.ylabel('Frequency (pitch)')
plt.grid()
ax.set_axisbelow(True)

# plotting with instrument as "color"

instruments = sorted(set(instrument.name for instrument in midi_data.instruments))

cm = plt.get_cmap('gist_rainbow')
instrument_colors = [cm(i/len(instruments)) for i in range(len(instruments))]

plt.figure(figsize=(15, 10))
ax = plt.gca()

starts = []
ends = []
pitches = []

for instrument in midi_data.instruments:
    instrument_name = instrument.name
    instrument_color = instrument_colors[instruments.index(instrument_name)]
    for note in instrument.notes:
        start = note.start
        end = note.end
        pitch = note.pitch
        velocity = note.velocity

        rect = matplotlib.patches.Rectangle((start, pitch - 0.5), end-start, 1, linewidth=1,
                                            edgecolor='k', facecolor=instrument_color, alpha=0.5)
        ax.add_patch(rect)
        
        starts.append(start)
        ends.append(end)
        pitches.append(pitch)
        
plt.ylim([min(pitches)-0.5, max(pitches) + 0.5])
plt.xlim([min(min(starts), 0), max(ends)])
plt.xlabel('Time (seconds)')
plt.ylabel('Frequency (pitch)')
plt.grid()
ax.set_axisbelow(True)

ax.legend([matplotlib.patches.Patch(linewidth=1, edgecolor='k', facecolor=c, alpha=0.5) for c in instrument_colors],
          instruments)

<matplotlib.legend.Legend at 0x7f85ad61d6a0>

Acknowledgment: This notebook was created by Frank Zalkow and Meinard Müller.