Delphi SAPI Text-To-Speech

Question

First of all: this is not a duplicate of Delphi and SAPI. I have a specific problem with the "SAPI in Delphi" subject.

I have used the excellent Import Type-Library guide in Delphi 2009 to get a TSpVoice component in the component palette. This works great. With

var
  SpVoice: TSpVoice;

I can write

SpVoice.Speak('This is an example.', 1);

to get asynchronous audio output.

First question

According to the documentation, I would be able to write

SpVoice.Speak('This is an example.', 0);

to get synchronous audio output, but instead I get an EZeroDivide exception. Why's that?

Second question

But more importantly, I would like to be able to create the SpVoice object dynamically (I think this is called to "late-bind" the SpVoice object), partly because only a very small fraction of all sessions of my app will use it, and partly because I do not want to assume the existance of the SAPI server on the end-user's system.

To this end, I tried

procedure TForm1.FormClick(Sender: TObject);
var
  SpVoice: Variant;
begin
  SpVoice := CreateOleObject('SAPI.SpVoice');
  SpVoice.Speak('this is a test', 0);
end;

which apparently does nothing at all! (Replacing the 0 with 1 gives me the EZeroDivide exception.)

Disclaimer

I am rather new to COM/OLE automation. I am sorry for any ignorance or stupidity shown by me in this post...

Update

For the benefit of everyone encountering the same problem as I did, the video by François explained there is a bug in SAPI/Windows (some incompatibility somewhere), which makes the following code raise the EZeroDivide exception:

procedure TForm1.FormClick(Sender: TObject);
var
  SpVoice: variant;
begin
  SpVoice := CreateOleObject('SAPI.SpVoice');
  SpVoice.Speak('This is a text.');
end;

The solution, as presented by the video, is to alter the FPU control word:

procedure TForm1.FormClick(Sender: TObject);
var
  SpVoice: variant;
  SavedCW: Word;
begin
  SpVoice := CreateOleObject('SAPI.SpVoice');
  SavedCW := Get8087CW;
  Set8087CW(SavedCW or $4);
  SpVoice.Speak('This is a text.');
  Set8087CW(SavedCW);
end;

And, in addition, if you want to play a sound asynchronously, then you have to make sure that the player doesn't go out of scope!

Answer 1

You may find interesting to see this CodeRage 4 session on "Speech Enabling Delphi Applications (zip)" You'll get the "how-to" you're looking for... (and I guess you are on Vista or + as the the zero divide did not happend on XP)

Answer 2

I was having the same problem in Delphi XE2. The Set8087CW(SavedCW or $4) solution presented in the question did not work for me. It merely replaced the division by zero exception with another floating point exception.

What did work for me is this:

SavedCW := Get8087CW;
SetFPUExceptionMask([exInvalidOp, exDenormalized, exZeroDivide, exOverflow, exUnderflow, exPrecision]);
SpVoice.Speak('All floating point exceptions disabled!', 0);
Set8087CW(SavedCW);