WORLD.jl

WORLD.jl is a Julia wrapper for WORLD - a high-quality speech analysis, manipulation and synthesis system. WORLD provides a way to decompose a speech signal into

• Fundamental frequency (F0)
• spectral envelope
• aperiodicity

and re-synthesize a speech signal from these paramters. Please see the project page for more details on the WORLD.

NOTE: WORLD.jl is based on a modified version of WORLD (r9y9/WORLD).

Supported Platforms

• Linux
• Mac OS X
• Windows

Installation

Run the following commands on your julia interactive settion (REPL):

julia> Pkg.add("WORLD")

if you want the latest master, run

julia> Pkg.clone("https://github.com/r9y9/WORLD.jl")
julia> Pkg.build("WORLD")

All dependencies are resolved with Pkg.clone and Pkg.build.

Usage

In the following examples, suppose x::Vector{Float64} is a input monoral speech signal like

F0 estimation and refinement

DIO

opt = DioOption(f0floor=71.0, f0ceil=800.0, channels_in_octave=2.0, period=period, speed=1)
f0, timeaxis = dio(x, fs, opt)

StoneMask

f0 = stonemask(x, fs, timeaxis, f0)

Spectral envelope estimation by CheapTrick

spectrogram = cheaptrick(x, fs, timeaxis, f0)

Aperiodicity ratio estimation by D4C

aperiodicity = d4c(x, fs, timeaxis, f0)

Synthesis

y = synthesis(f0, spectrogram, aperiodicity, period, fs, length(x))

Compact speech parameterization

Raw spectrum envelope and aperiodicity spectrum are relatively high dimentional (offen more than 513 or 1025) so one might want to get more compact representation. To do so, mel-cepstrum could be a good choice. As far as I know, this would be useful in statistical speech synthesis and statistical voice conversion.

spectrum envelope to mel-cepstrum

mc = sp2mc(spectrogram, order, α) # e.g. order=40, α=0.41

where order is the order of mel-cepstrum (except for 0th) and α is a frequency warping parameter.

mel-cepstrum to spectrum envelope

approximate_spectrogram = mc2sp(mc, α, get_fftsize_for_cheaptrick(fs))

aperiodicity spectrum to aperiodicity mel-cesptrum

ap_mc = sp2mc(aperiodicity, order, α) # e.g. order=40, α=0.41

NOTE: HTS v2.3 beta seems to parameterize aperiodicity spectrum in this way (but does this really make sense?).

aperiodicity mel-cepstrum to aperiodicity spectrum

approximate_aperiodicity = mc2sp(ap_mc, α, get_fftsize_for_cheaptrick(fs))

For the complete code of visualizations shown above, please check the ijulia notebook.