[hts-users:03481] Re: Question about HTS_lsp2mgc in hts_engine_API-1.06?

[Keiichi Tokuda <tokuda@xxxxxxxxxxxx>]

The reason why c(m) is converted to b(m) is
to avoid delay-free loops in the digital filter structure.

Keiichi


2012/11/26 ArthurLeo <bin007.zhao@xxxxxxxxxxx>:
> Thank you, I will double check the source code. I have the other question
> about c(m) and b(m).
> b(m) is the filter coefficients are used in the mglsa and mlsa filter(the
> attachment show the relationship between c(m) and b(m)). but why transform
> c(m) to b(m)? b(m) as the filter coefficients are much better than c(m)?
>
>> Date: Sun, 25 Nov 2012 16:06:06 +0000
>> From: heigazen@xxxxxxxxxx
>> Subject: [hts-users:03477] Re: Question about HTS_lsp2mgc in
>> hts_engine_API-1.06?
>> To: hts-users@xxxxxxxxxxxxxxx
>
>>
>> Hi,
>>
>> 2012/11/25 ArthurLeo <bin007.zhao@xxxxxxxxxxx>:
>>
>> > it's first step is HTS_lsp2lpc，
>> > second is HTS_mgc2mgc(v, mgc, m, alpha, v->gamma, mgc, m, alpha,
>> > v->gamma);
>> >
>> > I can not understand why using the function mgc2mgc？the lsp2lpc function
>> > has transform LSP to lpc，why added the mgc2mgc？especially the parameters
>> > transformed are same？
>> >
>> > As far as I know，mgc2mgc transforms mel-generalized cepstral
>> > coefficients;
>> > mgc2mgc can transform frequency and generalized cepstral
>> > ([alpha1、gamma1]
>> > -》[alpha12、gamma2])，but now the transformed parameters are same? why?
>> > mgc2mgc function is necessary?
>>
>> There are many forms of mel-generalized cepstral coefficients. For
>> example, mgcep supports 6 different forms of mel-generalized cepstral
>> coefficients as output (-o option, please refer to SPTK's reference
>> manual). However, mglsadf supports only a particular form of
>> mel-generalized cepstral coefficients (-o 0 in mgcep); mel-generalized
>> cepstral coefficients in the LPC form (-o 4 in mgcep if I remember
>> correctly) is not supported. Therefore, you need to convert
>> mel-generalized cepstral coefficients in the LPC form into those can
>> be used with mglsadf. HTS_mgc2mgc() performs this conversion.
>>
>> Regards,
>>
>> Heiga
>>
>> --
>> Heiga ZEN (in Japanese)
>> Byung Ha CHUN (in Korean)
>> <heigazen@xxxxxxxxxx>
>>