Joy of Think

Today, I am trying to use festival c/c++ api to say a word. After checking document, I decided to write an extension for ruby.
It is a simple task. All your need to do is:

Write a extension c file.

This file must define a function:
void Init_your_module_name()
It will be called on ruby loading it.
require "your_module_name"

In this function, generally, you must have following codes:


VALUE rb_mFestivalTTS;

rb_mFestivalTTS = rb_define_module( "FestivalTTS" ); //Define a module.
rb_define_module_function( rb_mFestivalTTS, "say", say, 1 ); //Define a function in module.


Write a extconf.rb

# extconf.rb
require 'mkmf'

dir_config('your_package_name')
create_makefile('your_package_name')


You can use find_library and find_header to add library and include path.

Run "make" command.


ruby extconf.rb
make


But it is a complex task too.

mkmf.rb doesn't support C

You must stick to C language.

You must be familiar with Ruby internal

All value passed bewteen extension and ruby inteperator is VALUE. It has a lot of api to manipuate VALUE. You must study <ruby.h>

Especially, you can use VALUE as a string by: StringValueCStr().

ruby定义了一个预定义的常量 RUBY_PLATFORM 可以用来实现平台判断.
在ubuntu 9.10下是 i386-linux
在windows下是i386-mswin32

festivaltts4r是ruby的一个gem,用来实现tts.分析它的代码,发现这是一个非常低效的实现,就是直接执行festival --tts的命令来发声.
festival本身提供festival-client模式和api模式,采用这两种应该可以提供更高效的实现.

Ubuntu uses festival as its TTS solution.

sudo aptitude install festival

But it has problem to work with PluseAudio and Bluetooth. For overcoming this problem, I found following wiki. Please notice following section "Configuration for ESD or PulseAudio"

• Open the configuration file by typing gksudo gedit /etc/festival.scm or gedit ~/.festivalrc in a terminal.
• Add the following lines at the end of the file:
  (Parameter.set 'Audio_Method 'esdaudio)
• Save the file.

java -jar file_name_of_jar