Ruby, Rock & Roll

Ruby, Rock and RollChang Sau SheongHP Labs SingaporeMay 2012

Musehttp://github.com/sausheong/muse

(pure)

domain- specific

language

synthesizing

Creating

Muse•Create

sound•Organize

notes•Write

file•Wrap

around

domain- specific

language

sound•Sound

produced

vibration

something

etc)•Vibration

produces

•Properties

include

amplitude

(volume)

frequency

(pitch)

Higher

amplitude

louder

volume amplitude frequency

number

cycles

second cycle More

cycles

second

higher

frequency,

higher

sound•Sine

sound,

sounds

combining

various

waves•To

sound,

generate

waves•To

digital

sound,

generate

digital

physics

music•Music

organized

sound•Music

sounds

specific

pitches

(frequencies)

durations•Each

corresponds

particular

frequency,

expressed

(Hz)•Most

(sequence

notes)

called

chromatic

(octave) C# D# F# G# A#C D E F G A B C 1

octave

semi-tone

physics

music•The

frequencies

formula•The

frequencies

defined

around

standard

16:1975

standard)•Notes

(octave)

A A7 3520HzA A6 1760HzA A5 880HzA A4 440Hz

12difference

between

semi-tones

octave)

12 1 difference

between

semi-tones

12 12 ×f

Getting

frequency•Get

frequency

compared

(440Hz)

formula n f = 2 × 440Hz 12•where

distance

(semi-tones)

frequency

3 f = 2 12 × 440Hz = 523.25Hz

Create

notes•To

representing

note s = sin(2π f )• We

multiple

because

π turn

frequency

radians

samples 1250 626 0 44100

samples take

samples

regular

intervals

(44,100

samples

period

second)

calculate

sample

NOTES = %w(a ais b c cis d dis e f fis g gis)FREQUENCIES = { d4:-7, dis4:-6, e4:-5, f4: -4, fis4:-3, g4:-2, gis4:-1, a4: 0, ais4: 1, b4: 2, c5: 3, cis5: 4, d5: 5}# get the frequency of the pitchdef frequency_of(step) 440.0*(2**(step.to_f/12.0))endsample_rate = 44100.0 # 44100 Hzduration = 1 # 1 secstream = [] # data stream for left and right channelsfrequency = frequency_of(FREQUENCIES[:a4])# for the duration of 1 sec, step every 1/44100 times and# write the value(0.0..duration.to_f).step(1/sample_rate) do |i| x = (10000 * Math.sin(2 * Math::PI * frequency * i)).to_i stream << [x,x]end

[[0, 0], [626, 626], [1250, 1250], [1869, 1869], [2481, 2481], [3083, 3083], [3673, 3673], [4248, 4248], [4807, 4807], [5347, 5347], [5866, 5866], [6362,6362], [6832, 6832], [7276, 7276], [7692, 7692], [8077, 8077], [8431, 8431], [8751, 8751], [9037, 9037], [9287, 9287], [9501, 9501], [9678, 9678], [9816,9816], [9916, 9916], [9978, 9978], [9999, 9999], [9982, 9982], [9925, 9925], [9830, 9830], [9696, 9696], [9523, 9523], [9313, 9313], [9067, 9067], [8785,8785], [8469, 8469], [8119, 8119], [7737, 7737], [7325, 7325], [6884, 6884], [6416, 6416], [5923, 5923], [5407, 5407], [4869, 4869], [4313, 4313], [3739,3739], [3151, 3151], [2550, 2550], [1939, 1939], [1321, 1321], [697, 697], [71, 71], [-555, -555], [-1179, -1179], [-1799, -1799], [-2412, -2412], [-3015,-3015], [-3606, -3606], [-4184, -4184], [-4744, -4744], [-5287, -5287], [-5808, -5808], [-6307, -6307], [-6780, -6780], [-7227, -7227], [-7646, -7646], stream[-8035, -8035], [-8392, -8392], [-8716, -8716], [-9006, -9006], [-9261, -9261], [-9479, -9479], [-9660, -9660], [-9803, -9803], [-9907, -9907], [-9973,-9973], [-9999, -9999], [-9986, -9986], [-9934, -9934], [-9843, -9843], [-9713, -9713], [-9545, -9545], [-9339, -9339], [-9097, -9097], [-8819, -8819],[-8506, -8506], [-8160, -8160], [-7782, -7782], [-7373, -7373], [-6936, -6936], [-6471, -6471], [-5981, -5981], [-5467, -5467], [-4931, -4931], [-4377,-4377], [-3805, -3805], [-3218, -3218], [-2619, -2619], [-2009, -2009], [-1391, -1391], [-768, -768], [-142, -142], [484, 484], [1109, 1109], [1729, 1729],[2343, 2343], [2947, 2947], [3540, 3540], [4119, 4119], [4682, 4682], [5226, 5226], [5750, 5750], [6251, 6251], [6728, 6728], [7178, 7178], [7600, 7600],[7992, 7992], [8353, 8353], [8681, 8681], [8975, 8975], [9234, 9234], [9456, 9456], [9641, 9641], [9788, 9788], [9897, 9897], [9967, 9967], [9998, 9998],[9989, 9989], [9942, 9942], [9855, 9855], [9729, 9729], [9566, 9566], [9364, 9364], [9126, 9126], [8852, 8852], [8544, 8544], [8201, 8201], [7827, 7827],[7421, 7421], [6987, 6987], [6525, 6525], [6038, 6038], [5526, 5526], [4993, 4993], [4441, 4441], [3871, 3871], [3285, 3285], [2687, 2687], [2079, 2079],[1462, 1462], [839, 839], [213, 213], [-413, -413], [-1038, -1038], [-1659, -1659], [-2273, -2273], [-2879, -2879], [-3473, -3473], [-4054, -4054], [-4619,-4619], [-5165, -5165], [-5691, -5691], [-6195, -6195], [-6675, -6675], [-7128, -7128], [-7554, -7554], [-7949, -7949], [-8314, -8314], [-8645, -8645],[-8943, -8943], [-9206, -9206], [-9432, -9432], [-9622, -9622], [-9774, -9774], [-9887, -9887], [-9961, -9961], [-9996, -9996], [-9992, -9992], [-9949,-9949], [-9867, -9867], [-9746, -9746], [-9586, -9586], [-9389, -9389], [-9155, -9155], [-8885, -8885], [-8580, -8580], [-8242, -8242], [-7871, -7871],[-7469, -7469], [-7038, -7038], [-6579, -6579], [-6094, -6094], [-5586, -5586], [-5055, -5055], [-4504, -4504], ...]

Harmonics•Sine

waveform

produces

fundamental

frequency,

sound•Any

sounds

created

adding

different

frequencies

amplitudes

(called

harmonics)•Adding

different

multiples

frequency

changes

sounds

y=sin(x)y

sin(2x) y

sin(x)

sin(2x)

def harmonics(input) Math.sin(2 * Math::PI * input) + Math.sin(2 * Math::PI * input * 2)end# for the duration of 1 sec, step every 1/44100 times and# write the value(0.0..duration.to_f).step(1/sample_rate) do |i| x = (10000 * harmonics(frequency * i)).to_i stream << [x,x]end

Envelopes•Changing

volume

duration

changes

sounds def envelope(input, duration) Math.cos((Math::PI*input)/(2*duration.to_f)) end # for the duration of 1 sec, step every 1/44100 times and # write the value (0.0..duration.to_f).step(1/sample_rate) do |i| x = (10000 * Math.sin(2 * Math::PI * frequency * i) * envelope(i, duration)).to_i stream << [x,x] end

sin(duration)input

cos(duration)

sin(duration)input

cos(duration)

sin(duration)input

cos(duration)

Digital

sound•Digital

stored

compressed

uncompressed

formats•Main

uncompressed

format

(Pulse

Modulation),

stored

(Windows)

files•Standard

digital

audio,

digital

representation

analog

signal

format•Audio

format

Windows,

derived

(Resource

Interchange

Format)•Bitstream

format

chunks•Linear

encoded,

channels

44,100

samples

second,

sample

Create

files•Write

manually

Array#pack

manually

String#unpack)•Use

BinData

library

(http:// bindata.rubyforge.org)

represent

format

in•Data

integers

representing

sample

require bindataclass RiffChunk < BinData::Record int32be :chunk_id int32le :chunk_size int32be :formatendclass FormatChunk < BinData::Record int32be :chunk_id int32le :chunk_size int16le :audio_format int16le :num_channels int32le :sample_rate int32le :byte_rate int16le :block_align int16le :bits_per_sampleendclass DataChunk < BinData::Record int32be :chunk_id int32le :chunk_size array :stream do int16le :left int16le :right endendclass WavFormat < BinData::Record riff_chunk :riff_chunk format_chunk :format_chunk data_chunk :data_chunkend

class Wav SAMPLE_RATE = 44100 attr :wav, :file, :sample_rate, :format_chunk, :riff_chunk, :data_chunk def initialize(filename) @sample_rate = SAMPLE_RATE @file = File.open(filename, "wb") @riff_chunk = RiffChunk.new @riff_chunk.chunk_id = "RIFF".unpack("N").first @riff_chunk.format = "WAVE".unpack("N").first @format_chunk = FormatChunk.new @format_chunk.chunk_id = "fmt ".unpack("N").first @format_chunk.chunk_size = 16 @format_chunk.audio_format = 1 @format_chunk.num_channels = 2 @format_chunk.bits_per_sample = 16 @format_chunk.sample_rate = @sample_rate @format_chunk.byte_rate = @format_chunk.sample_rate * @format_chunk.num_channels * @format_chunk.bits_per_sample/2 @format_chunk.block_align = @format_chunk.num_channels * @format_chunk.bits_per_sample/2 @data_chunk = DataChunk.new @data_chunk.chunk_id = "data".unpack("N").first end

def write(stream_data) stream_data.each_with_index do |s,i| @data_chunk.stream[i].left = s[0] @data_chunk.stream[i].right = s[1] end @data_chunk.chunk_size = stream_data.length * @format_chunk.num_channels * @format_chunk.bits_per_sample/8 @riff_chunk.chunk_size = 36 + @data_chunk.chunk_size @wav = WavFormat.new @wav.riff_chunk = @riff_chunk @wav.format_chunk = @format_chunk @wav.data_chunk = @data_chunk @wav.write(@file) end def close @file.close endendwav_file = Wav.new(sine.wav)wav_file.write(stream)wav_file.close

Putting

together

NOTES = %w(a ais b c cis d dis e f fis g gis)FREQUENCIES = { d4:-7, dis4:-6, e4:-5, f4:-4, fis4:-3, g4:-2, gis4:-1, a4: 0, ais4: 1, b4: 2, c5: 3, cis5: 4, d5: 5}# get the frequency of the pitchdef frequency_of(step) 440.0*(2**(step.to_f/12.0))endsample_rate = 44100.0 # 44100 Hzduration = 1 # 1 secstream = [] # data stream for left and right channelsfrequency = frequency_of(FREQUENCIES[:a4])# for the duration of 1 sec, step every 1/44100 times and# write the value(0.0..duration.to_f).step(1/sample_rate) do |i| x = (10000 * Math.sin(2 * Math::PI * frequency * i)).to_i stream << [x,x]endwav_file = Wav.new(sine.wav)wav_file.write(stream)wav_file.close

Domain

specific

language•Designed

specific

domain•Captures

concepts

domain

including

jargon•Is

Techniques

Muse•DSL

methods

Bar•Use

instance_eval

evaluate

score•Use

method_missing

chords

class Song DSL

methods def self.record(name, options ={}, &block) ... def bar(id, options={}) ... @bars[id] << Bar.new(id, options) @bars[id].last end end class Bar def notes(&block) ... end end endrequire "muse"include MuseSong.record hotel_california, harmonic: guitar, bpm: 100 do bar(1).notes { d4 b:2; e4; fis4;} ...end

instance_evalclass Bar ... def notes(&block) instance_eval &block endendrequire "muse"include MuseSong.record hotel_california, harmonic: guitar, bpm: 100 do bar(1).notes { d4 b:2; e4; fis4;} ...end

method_missingclass Bar ... def method_missing(name, *args, &block) name = name.to_s if name.start_with? *NOTES ... end endendrequire "muse"include MuseSong.record hotel_california, harmonic: guitar, bpm: 100 do ... bar(3).notes { a3_d4_fis4; fis4; fis4 b:0.5;} ...end

Turk!h March

there’s

Ottothe Algorithmic Composer

Algorithmic composition is thetechnique of using algorithms to create music - Wikipedia

Grab tweet from Twitter, create music from it

Scan a pictureGrab tweet from Twitter, create music from it

Get today’s weather report Scan a picture Grab tweet from Twitter, create music from it

The algorithm

Melody + Chords = Music

Grab tweet from Twittertext = Twitter.search("#reddot").last.text

Split tweet into wordswords = text.split

Convert each word into anumber using the touch tone keypad algorithm

KEYPAD = {a:2,b:2,c:2, d:3,e:3,f:3, g:4,h:4,i:4, j:5,k:5,l:5, m:6,n:6,o:6, p:7,q:7,r:7,s:7, t:8,u:8,v:8, w:9,x:9,y:9,z:9}def word_to_num(a_word) a_word.downcase.chars.inject("") { |memo,obj| memo + KEYPAD[obj.to_sym].to_s }end

Find the 7 most frequently found notesmusic = []words.each do |w| music << NOTES[note(w)]endsorted = music.counts.sort_by {|obj| obj[1]}.reversemost_frequent_7_notes = sorted.map {|obj| obj[0]}.first(7)

Determine the musical scale from the 7 notesMAJOR = { 0 => %w(c d e f g a b c d), 1 => %w(g a b c d e fis g a), 2 => %w(d e fis g a b cis d e), 3 => %w(a b cis d e fis gis a b), 4 => %w(e fis gis a b cis dis e fis), 5 => %w(b cis dis e fis gis ais b cis), 6 => %w(fis gis ais b cis dis f fis gis) }num_of_sharps = most_frequent_7_notes.inject(0) { |memo, obj| obj.end_with?("is") ? memo + 1 : memo }scale = MAJOR[num_of_sharps]

Get the chord progression for the scale (using I-IV-V)scale_chords = {}scale_chords[0] = ["#{scale[0]}", "#{scale[2]}", "#{scale[4]}"]scale_chords[1] = ["#{scale[3]}", "#{scale[5]}", "#{scale[7]}"]scale_chords[2] = ["#{scale[4]}", "#{scale[6]}", "#{scale[8]}"]

✓Melody + Chords = Music

Start with the ﬁrst note of the scale

Calculate the ‘distance’ between the current note and the nextdef distance(a_word) word_to_num(a_word).to_i % 5end

Determine if the next note goes ‘up’ or ‘down’ the scaledef direction(a_word) (word_to_num(a_word).to_i % 2) == 0 ? 1 : -1end

Get number of syllables for each word, each syllable is 1 beatdef syllables(a_word) word = a_word.downcase return 1 if word.length <= 3 word.sub!(/(?:[^laeiouy]es|ed|[^laeiouy]e)$/, ) word.sub!(/^y/, ) word.scan(/[aeiouy]{1,2}/).sizeend

Move from current note to next noteif direction(word) > 0 bar_notes << scale.next(distance(word))else bar_notes << scale.previous(distance(word))end

✓ ✓Melody + Chords = Music

Break down into 4 words perbar, use Muse to write to WAV ﬁle

quadruplets.reverse.each_with_index do |quad, index| beats = 0.0 bar(index).notes { beats, bar_notes = [], [] quad.each do |word| beats << syllables(word).to_f/2 if direction(word) > 0 bar_notes << scale.next(distance(word)) else bar_notes << scale.previous(distance(word)) end end total_beats = beats.inject(:+) bar_notes.each_with_index do |n,i| note = n.chop octave = n[n.size-1] b = (beats[i]*4.0)/total_beats add_to_stream note_data(note, octave, b:b) end } bar(index, v:1.5).notes { ch = scale_chords[index % 3] chord = [ch[1], ch[2], ch[0]] add_to_stream note_data(ch[0].chop, 3, b:1) add_to_stream chord(chord, b:1) add_to_stream chord(chord, b:1) add_to_stream chord(chord, b:1) }

@sausheong+Sau Sheong Changsausheong@gmail.comsausheong@hp.comhttp://blog.saush.com

Ruby, Rock & Roll

by Sau Sheong Chang

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Ruby, Rock & Roll

by Sau Sheong Chang

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Ruby, Rock & Roll Presentation Transcript

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