2.05 Stay in Instrument Range ============================= In the Previous example the melody could get **off track** and get further away from the **good sounding instrument range.** It was also possible that it left the scale and created an error. The Melody generation has new concept. The **intervals are now generated step by step (intvl\_next**) with an for-loop. Each interval is first added to the melody and then checked for acceptance. The **range provides the acceptance values** over the seven Midi-Octaves. At the moment a linear range is used, but it could be easily be changed in a Beta-Curve. The **acceptance function** decides whether the **proposed interval is accepted** or if an new proposal must be made. 1. first the acceptance values of the current and proposed note are read out of the range. 2. then the acceptance value of the current note is divided by the acceptance value of the proposed note. 3. This quotient is compared with an random number from 0 to 1. If Quotient > Random number, the proposed interval is accepted. Otherwise an new proposition is requested. This is an **Metropolis-Hasting Algorithm**. .. code:: python3 from pyknon.genmidi import Midi from pyknon.music import Rest, Note, NoteSeq import numpy as np import matplotlib.pyplot as plt **Instruments:** Available are at lest the 128 General-Midi (GM) Instruments. Depending on the sound-fonts there is a bigger choice. A list of the GM instruments can be found here. https://jazz-soft.net/demo/GeneralMidi.html .. code:: python3 major = np.array([ 0, 2, 4, 5, 7, 9, 11]) minor = np.array([ 0, 2, 3, 5, 7, 8, 10]) blues = np.array([ 0, 3, 5, 6, 7, 10]) C7 = np.array([ 0, 4, 7, 10]) CM7 = np.array([ 0, 4, 7, 11]) def scale_create(tones): tones = np.asarray(tones) # tones which form chord or scale in the first octave (0-11) if any(tones > 11): # tones over one octave? tones = np.mod(tones,12) # set the thones in one octave tones = np.sort(tones) # sort the tones new tones = np.unique(tones) # remove duplicate tones octave = np.repeat( np.linspace(0,108, num=10), len(tones)) scale = np.add( octave, np.tile(tones, 10)) # add element wise octave and note return scale.astype(int) def fade(start,end,steps): # currently not in use fade = np.around( np.linspace(start,end,num=steps)) fade = fade.astype(int) return fade def ran_duration(duration, prob_duration, melody_len): duration= np.asarray(duration) # this are the allowed durations of the notes prob_duration = np.asarray(prob_duration) # this are the probabilities how often each will occure prob_duration = prob_duration/np.sum(prob_duration) rythem = np.r_[np.random.choice(duration, size=melody_len, p=prob_duration)] return rythem def ran_volume(volume, prob_volume, melody_len): volume = np.asarray(volume, dtype=int) # this are the allowed volumes of thenotes prob_volume = np.asarray(prob_volume) # this are the probabilities how often each volume will occure prob_volume = prob_volume/np.sum(prob_volume) volumes = np.r_[np.random.choice(volume, size=melody_len, p=prob_volume)] return volumes def intvl_melody(intvl, prob_intvl, melody_len): #Interval Melody # currently not in use intvl = np.asarray(intvl) # Possible interval prob_intvl = np.asarray(prob_intvl) # Probability of each interval prob_intvl = prob_intvl/np.sum(prob_intvl) intervals = np.r_[np.random.choice(intvl, size=melody_len, p=prob_intvl)] imelody = np.cumsum(intervals) return imelody **linear\_range:** Generates the acceptance values. They define the range in which the instrument can play. .. code:: python3 def liniar_range(r_start, r_top, r_edge, r_end, title): # acceptance range of the instrument h = 100 # hight of acceptance function a_range = np.zeros(121, dtype=int) # only to midi =120 as 127 is not a complete octave np.put(a_range, range(r_start,r_top), np.linspace(0,h, num=(r_top -r_start)) ) np.put(a_range, range(r_top, r_edge), np.linspace(h,h, num=(r_edge-r_top )) ) np.put(a_range, range(r_edge, r_end), np.linspace(h,0, num=(r_end -r_edge )) ) fig, ax = plt.subplots() ax.plot(range(121), a_range) plt.title(str(title)+': '+str([r_start, r_top, r_edge, r_end])) plt.show() return a_range **i\_last\_note:** finds the i value of the last note in the actual scale. .. code:: python3 def i_last_note(note, scale): i_note = (np.abs(scale - note)).argmin() return i_note **intvl\_next** is a modification of intvl\_melody. But it does only creates **one** interval and not an array/melody in one time. .. code:: python3 def intvl_next(intvl, prob_intvl): #singel interval intvl = np.asarray(intvl) # Possible interval prob_intvl = np.asarray(prob_intvl) # Probability of each interval prob_intvl = prob_intvl/np.sum(prob_intvl) interval = np.random.choice(intvl, size=1, p=prob_intvl) return interval[0] **acceptance** decides with an Metropolis-Hasting Algorithm whether the Proposed not is accepted. .. code:: python3 # x is the aceptance value of the current note, while x_new is it from the proposoal note. def acceptance(x, x_new): if x_new < 1: if x < 1: print('start_note not in range') return quot = x_new/x if quot >= 1: return True if np.random.uniform(0,1)< quot: return True else: return False .. code:: python3 def acceptance_melody(intvl, prob_intvl, scale, start_note, a_range, melody_len): melody = np.zeros(melody_len, dtype=int) melody[0] = scale[i_last_note(start_note,scale)] for npn in range(1, melody_len): accept = False while not accept: # aslong acept == False inote = i_last_note(melody[npn-1],scale) inote_next = inote + intvl_next(intvl, prob_intvl) # add current not with Proposition accept_val = a_range[[melody[(npn-1)],scale[inote_next]]] # get acceptance values accept = acceptance(accept_val[0],accept_val[1]) melody[npn] = scale[inote_next] print('melody:',melody) return melody **tune\_P:** Changing the scale creating method. .. code:: python3 def tune_P(): tune_name = 'tune_P' #np.random.seed(23) melody_len = 60 scale = scale_create(blues) range_1 = liniar_range(48,56,72,78,'Range1') melody1 = acceptance_melody([-2,-1, 0, 1, 2],[1, 3, 1, 3, 1],scale, 60, range_1, melody_len) rythem1 = ran_duration([1/8, 1/4,1/2], [4,2,1], melody_len) volumes1 = ran_volume([0,120], [1,8], melody_len ) notes1 = NoteSeq( [Note(no,octave=0, dur=du, volume=vo) for no,du,vo in zip(melody1,rythem1,volumes1)] ) instruments = [24] notes = [notes1] return notes, instruments,tune_name .. raw:: html
tune_P
tune_P


.. code:: python3 def gen_midi(): # squezze into a MIDI framework notes, instruments, tune_name = tune_P() # <--- select a tune <<-- <<<<<<<<<--- select a tune ----- nTracks = len(notes) m = Midi(number_tracks=nTracks, tempo=120, instrument=instruments) for iTrack in range(nTracks): m.seq_notes(notes[iTrack], track=iTrack) #--- write the MIDI file ----- midi_file_name = tune_name +'.mid' # set the name of the file m.write(midi_file_name) return midi_file_name Midi: Play and Generate audio-file ---------------------------------- External players offered a better sound quality in comparison with python libraries. We use **VLC** and **Musescore**. The **soundfont** for the VLC player is defined over the command line. For Musescore through the Gui in the preferences. .. code:: python3 import subprocess default_soundfont = '/usr/share/sounds/sf3/MuseScore_General.sf3' def midi_play(midi_in, soundfont= default_soundfont): subprocess.call(['cvlc', midi_in , 'vlc://quit', '--soundfont', '/home/viturin/-vitis/Documents/MuseScore2/Soundfonts/Compifont_13082016.sf2']) # cvlc = vlc without gui def midi_audio(midi_in, name_out = 'none', soundfont= default_soundfont): if name_out == 'none' : name_out = midi_in.replace('.mid', '.flac') else: name_out = name_out + '.flac' subprocess.call(['mscore', '-o', name_out, midi_in]) # -o = export as def midi_png(midi_in, name_out = 'none'): if name_out == 'none' : name_out = midi_in.replace('.mid', '.png') else: name_out = name_out + '.png' subprocess.call(['mscore', '-o', name_out, '-T', '2', midi_in]) # -o = export as , -T 2 = cut page with 2 pixel .. code:: python3 ######--- Main ---###### midi_file_name = gen_midi() midi_play(midi_file_name) midi_audio(midi_file_name) midi_png(midi_file_name) .. image:: output_19_0.png .. parsed-literal:: melody: [60 55 60 58 60 55 54 55 58 60 60 65 66 63 66 63 66 67 70 67 70 72 70 72 67 72 72 70 72 70 72 72 67 67 67 67 67 72 70 75 72 70 70 72 70 72 70 67 70 66 70 70 67 70 66 65 65 63 66 63]