[hts-users:01798] Re: F0 modelling

["Heiga Zen (Byung Ha CHUN)" <heiga.zen@xxxxxxxxxxxxxxxxx>]

Hi,

Javi Palenzuela wrote:

> After reading the papers, the mailing list and looking at the code, I
> still don't understand at 100% how the voiced/unvoiced decision is
> practically trained using MSD.
>
> I see that the decision is made using the weight of the mixture of the
> first stream. In the data, LZERO is used to flag the unvoiced regions.
> But how is the weight updated accordingly with this?

Frames containing LZERO as their F0 values are unvoiced.  Other frames 
are voiced.  By running the Forward-Backward algorithm, you can get the 
state occupancy probability for each frame.  Using state occupancy 
probability, you can get the following information:

#UV -> total occupancy counts of unvoiced frames assigned to this state
#V  -> total occupancy counts of voiced   frames assigned to this state

Then, you can estimate weights for V/UV as follows:

weight_uv = #UV / (#UV + #V)
weight_v  = #V  / (#UV + #V)

At the synthesis stage, if weight_v>=0.5, this state is treated as 
voiced, otherwise unvoiced.

Regards,

Heiga ZEN (Byung Ha CHUN)

--
--------------------------
Heiga ZEN (Byung Ha CHUN)
Speech Technology Group
Cambridge Research Lab
Toshiba Research Europe
phone: +44 1223 436975

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