[Espeak-general] eSpeak calling mbrola

[Jonathan D. <jo...@ta...>]

Mbrola on linux is only available as a command-line program, not a
shared library.  So eSpeak produces mbrola phoneme information as text
which can then be piped into mbrola.

Nicolas Pitre (author of the Cicero front end for the mbrola French
voice) has now written code for eSpeak which emulates the mbrola
library on Windows.  This means that the command-line version of eSpeak
and the Linux libespeak can now call mbrola directly.

espeak -v mb-en1 "Hello world"

will now speak using the mbrola "en1" voice.  Previously this needed
something like:

espeak -v mb-en1 "Hello world" | mbrola -e /usr/share/mbrola/en1 - - |
aplay -r 16000 -f S16_LE
 
eSpeak can still generate mbrola phoneme output as text (mbrola .pho
file) by using the new --pho command-line option, eg:

espeak -v mb-en1 --pho "Hello world"

On Linux, eSpeak will look for mbrola voices firstly in
espeak-data/mbrola  and then in /usr/share/mbrola.

On Windows it looks only in espeak-data/mbrola.

A complication is that most mbrola voices have a sample rate of 16000
Hz instead of the eSpeak rate of 22050 Hz.  Speaking text which
contains SSML commands which change between eSpeak and mbrola voices or
between voices of different sample rates doesn't work.  In theory it
may be possible to stop the sound output channel and re-initialise it
at a different sample rate, but my initial attempt with portaudio
failed.