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MeloSynth: synthesize a melody.
Author: Justin Salamon
Version: 0.1.1

MeloSynth is a python script to synthesize melodies represented as a sequence of pitch (frequency) values. It was written to synthesize the output of the MELODIA Melody Extraction Vamp Plugin, but can be used to synthesize any pitch sequence represented as a two-column txt or csv file where the first column contains timestamps and the second contains the corresponding frequency values in Hertz.


usage: [-h] [--output OUTPUT] [--fs FS] [--nHarmonics NHARMONICS]
                    [--square] [--useneg] [--batch]

positional arguments:
  inputfile             Path to input file containing the pitch sequence

optional arguments:
  -h, --help            show this help message and exit
  --output OUTPUT       Path to output wav file. If not specified a file will
                        be created with the same path/name as inputfile but
                        ending with "_melosynth.wav".
  --fs FS               Sampling frequency for the synthesized file. If not
                        specified the default value of 16000 Hz is used.
  --nHarmonics NHARMONICS
                        Number of harmonics (including the fundamental) to use
                        in the synthesis (default is 1). As the number is
                        increased the wave will become more sawtooth-like.
  --square              Converge to square wave instead of sawtooth as the
                        number of harmonics is increased.
  --useneg              By default, negative frequency values (unvoiced
                        frames) are synthesized as silence. Setting the
                        --useneg option will synthesize these frames using
                        their absolute values (i.e. as voiced frames).
  --batch               Treat inputfile as a folder and batch process every
                        file within this folder that ends with .csv or .txt.
                        If --output is specified it is expected to be a folder
                        too. If --output is not specified, all synthesized
                        files will be saved into the input folder.


Basic usage, without any options:

>python ~/Documents/daisy3_melodia.csv

This will create a file called daisy3_melodia.wav in the same folder as the input file (~/Documents/) and use all the default parameter values for the synthesis.

Advanced usage, including options:

>python ~/Documents/daisy3_melodia.csv --output ~/Music/mynewfile.wav --fs 44100 --nHarmonics 10 --square --useneg

Here we are providing a specified path for the output instead of the default location. Next we specify the sample rate for the output (44.1 kHz) instead of the default value of 16000 Hz. Next, we specify the number of harmonics to use (10) instead of the default value of 1. Normally, as the number of harmonics is increased the waveform will converge to a sawtooth wave, however, since we specify the --square option, it will converge to a square wave instead. Finally, by specifying the --useneg (use negative) option we make the script use the absolute value of the frequencies so that negative frequencies are not synthesized as silence (which is the default behaviour).

Batch processing:

>python ~/Documents/melodia_pitch/ --output ~/Documents/melodia_synth/ --batch

This will batch process all files ending with .txt or .csv in the melodia_pitch folder, and save the synthesized melodies into the melodia_synth folder. Every synthesized file will have the same name as its corresponding input file but with the ending _melosynth.wav.


Simply download the script and run it from your terminal as instructed above.
Dependencies: python (tested on 2.7) and numpy (

Melodia users

In order to use this script to synthesize the output of MELODIA, you need to export the melody to a CSV file first. If you are using Sonic Visualiser, this is done by selecting the pane with the extracted melody, clicking File -> Export Annotation Layer... and choosing CSV as the file type. You can also obtain the CSV directly (and batch process entire folders of files) by using MELODIA with Sonic Annotator (see instructions in the README file that comes with MELODIA for this).


MeloSynth: synthesize a melody
Copyright (C) 2018 Justin Salamon.

MeloSynth is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

MeloSynth is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see