Proper `Language` attribute handling for SAPI5 voices

[gexgd0419]

The current code assumes that the attribute Language of SAPI5 voices only has one hexadecimal value:

pyttsx3/pyttsx3/drivers/sapi5.py

Lines 105 to 109 in 7f11076

	# Retrieve and convert language code
	language_attr = attr.GetAttribute("Language")
	language_code = int(language_attr, 16)
	primary_sub_code = f"{language_code & 0x3FF}-{(language_code >> 10) & 0x3FF}"
	languages = [lcid_to_locale(primary_sub_code)]

However, SAPI5 allows multiple values separated by semicolons, so that a voice can put all supported language IDs here, or put neutral locale IDs as a fallback. The current code would fail if there are multiple values, such as 409;809.

SpGetLanguageFromToken in sphelper.h handles this by taking only the first value:

// ...
const WCHAR *pszLangId = dstrLanguage;
WCHAR achHexNumber [5]; // LangIds cannot be more than 4 characters longs

// check if the langid is in the format "409;9" - extract the "409" in this case
const WCHAR *pSemiColon = wcschr (pszLangId, L';');
if (pSemiColon)
{
    size_t cLen = pSemiColon - dstrLanguage;
    if (cLen <= 4)
    {
        StringCbCopyNW (achHexNumber, sizeof (achHexNumber), dstrLanguage, cLen * sizeof (achHexNumber [0]));
        pszLangId = achHexNumber;
    }
}
// ...

You can also list all languages in this case.

[cclauss]

This sounds useful to me. Could you please propose a pytest that fails because pyttsx3 is currently doing the wrong thing?

[gexgd0419]

Built-in voices in the Windows XP era do have language attributes like 409;9. 409 means English (United States), while 9 means region-neutral English. It works as a fallback: since other English locales such as 809 (English (United Kingdom)) won't match 409, it adds a neutral 9 in the hope that applications may use multiple language IDs as matching criteria. So in this case, its main language is still 409.

But built-in voices in Windows 10/11 only have one language ID. This means that you'll have to find some third-party voices, or mock a voice object that does this kind of thing, in order to test this.

I'd also suggest wrapping every GetAttribute call with try...except. SAPI5 raises an error when the specified attribute does not exist for the voice. And since pyttsx3 uses None for unknown attributes, maybe it needs to handle the "not found" case as well.

By the way, does pyttsx3 support listing multiple languages for a single voice?

[baifangkual]

Hello, I encountered this issue: I used https://github.com/gexgd0419/NaturalVoiceSAPIAdapter to download and install some Msix-format offline voice packages that I needed on my Windows 11 system. After installing these voice packages, when I use pyttsx3's voices = engine.getProperty('voices') to get all available voices, internally in the function, language_attr = attr.GetAttribute("Language") is called. For this particular voice, the language_attr value is '804;4;7804', which causes an exception when language_code = int(language_attr, 16) is executed...

The temporary workaround I'm using is through:

engine.setProperty('voice', 'HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Speech\\Voices\\TokenEnums\\NaturalVoiceEnumerator\\Local-MicrosoftWindows.Voice.zh-CN.Xiaoxiao.1')

This bypasses the language_code = int(language_attr, 16) process...

Complete stack trace:

  File "C:\Users\baifangkual\bfkApplication\JetBrainsIDEs\ToolBox\PyCharm Professional\plugins\python-ce\helpers\pydev\pydevd.py", line 1648, in _exec
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "C:\Users\baifangkual\bfkApplication\JetBrainsIDEs\ToolBox\PyCharm Professional\plugins\python-ce\helpers\pydev\_pydev_imps\_pydev_execfile.py", line 18, in execfile
    exec(compile(contents+"\n", file, 'exec'), glob, loc)
  File "C:\Users\baifangkual\Desktop\Code\python\15000VoiceGen\Text2Voice.py", line 36, in <module>
    text2voice(str_list)
  File "C:\Users\baifangkual\Desktop\Code\python\15000VoiceGen\Text2Voice.py", line 18, in text2voice
    voices = engine.getProperty('voices')
  File "C:\Users\baifangkual\Desktop\Code\python\15000VoiceGen\.venv\lib\site-packages\pyttsx3\engine.py", line 187, in getProperty
    return self.proxy.getProperty(name)
  File "C:\Users\baifangkual\Desktop\Code\python\15000VoiceGen\.venv\lib\site-packages\pyttsx3\driver.py", line 165, in getProperty
    return self._driver.getProperty(name)
  File "C:\Users\baifangkual\Desktop\Code\python\15000VoiceGen\.venv\lib\site-packages\pyttsx3\drivers\sapi5.py", line 133, in getProperty
    return [self._toVoice(attr) for attr in self._tts.GetVoices()]
  File "C:\Users\baifangkual\Desktop\Code\python\15000VoiceGen\.venv\lib\site-packages\pyttsx3\drivers\sapi5.py", line 133, in <listcomp>
    return [self._toVoice(attr) for attr in self._tts.GetVoices()]
  File "C:\Users\baifangkual\Desktop\Code\python\15000VoiceGen\.venv\lib\site-packages\pyttsx3\drivers\sapi5.py", line 107, in _toVoice
    language_code = int(language_attr, 16)
ValueError: invalid literal for int() with base 16: '804;4;7804'