API - usando o speech do windows para ler textos
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How can I get my application to read text?
How to Add Speech Synthesis (a.k.a Text to Speech) to your Delphi Apps.
On Aug 11, 2001 Microsoft released the SAPI 5.1 SDK. This is significant
because SAPI 5.1 is fully automated. That is you can use it from any
language that supports OLE automation. These are not Active X controls
and can be either early or late bound.
In this article I’m going to show you how to get and install the SAPI 5.1
SDK. Then I’m going to show how to use the SDK convert text to
synthesized speech in a Delphi application. The synthesized speech is
played over you computers speakers. I test this in Delphi 5 and 6.
To get SAPI 5.1 you need to go to Microsoft’s Speech.net Technologies
web site at http://www.microsoft.com/speech/ and follow the link to the
download. Right next to the download link is the release notes link.
READ THE RELEASE NOTE! Especially if your development machine is using
a default language other than US English.
If you are running a beta version of the XP operating system you might
have some problems. This is because SAPI 5.1 is built into XP and the most
recent public beta of XP as of this writing (RC 2) includes an earlier
version of SAPI 5.1. Don’t try to install the release version of SAPI 5.1
into XP, it will not work.
Once you read the release notes follow the link to the Speech SDK 5.1
Download page. In most cases all you need to download is the link labeled
“Speech SDK 5.1 (68 MB). This contains the SDK, the documentation and
the free Microsoft English text to speech and speech recognition engines.
The download is very large, 68 MB, so unless you have a high speed
connection to the internet you might want to order the SDK CD from Microsoft.
…. Time passes while you download or wait for the postman ….
Ok, now you have the SAPI 5.1 SDK. Run the speechsdk51.exe to install it
on your development system.
[ *** DELPHI 6 Users IMPORTANT ****
There is a bug in the type library import in Delphi 6 see article 2589.
This sample will still work with the unit created by the type libary import
in Delphi 6 but only because none of the events for the component are used.
If you want to use any of the SPVoice events you will need to read article
What you need to do now is make Delphi aware of the new SAPI automation
objects. To do this, start up Delphi 5 or 6 (I didn’t try earlier versions)
and go to Project | Import Type Library. In the Import Type Library
dialog highlight “Microsoft Speech Object Library (Version 5.1)”.
If you don’t find this in the list then something’s wrong with the
installation of SAPI 5.1.
Delphi is going to want to put the SAPI components on your ActiveX palette
page. I recommend you put these on a new palette page called “SAPI 5” since
the number of components installed is large (19). You may also want to choose
a “Unit dir name” of something other than the default. Make sure the
“Generate Component Wrapper” check box is checked and press the
In the Install dialog choose the “Into new package” tab and in the
“File name:” field give a package name like “SAPI5.dpk” press the browse
button and make sure the dpk is created in the same directory where you
created the components. Actually this isn’t completely necessary it just
helps keep things together. In the Install dialog’s Description field give
some meaningful description like “SAPI 5 automation components”. Press OK
Press yes in the confirm dialog and the new components will be created
If you now look in the directory you specified for the components you
should find SpeechLib_TLB.pas (and dcr) which contains all the component
code as well as interface, const, type and other useful information.
This is your most valuable piece of documentation on the SDK. I’ve found
it even better than the Microsoft SAPI 5.1 documentation which is pretty good.
This directory should also contain (if you followed the above instructions)
the SAPI5.dpk which is your package source.
If you go to the far eastern end of your component palette you should find
the new SAPI5 palette page with its 19 speech components.
Now for the fun part.
Let’s make an application that can synthesize speech. In Delphi start a new
application and drop a button on the form. On the SAPI5 palette page find
the SpVoice component and drop it on the form. On my machine this component
is the 5th one reading from left to right.
Now create an onClick event for you button that looks something like this;
procedure TForm1.Button1Click(Sender: TObject);
SpVoice1.Speak('Hello world!', SVSFDefault);
Run the program and press the button. Cool hu?
At this level it’s amazingly simple. The SPVoice objects Speak method is
very powerful. This power comes from the second parameter.
For the above example I choose to use the default mode which causes the
speak method to return only when the synthesis is complete, not to purge
pending speech requests, to respond to special XML control tags embedded
in the text.
The SDKs documentation is contained in sapi.chm which you will find in the
\Program Files\Microsoft Speech SDK 5.1\Docs\Help directory.
Sapi.chm contains a lot of information. To go directly to the meat of
the subject go to the last folder on the outlines 1st level titled Automation
and go down to SPVoice and then to the Speak method read what’s there and also
be sure to follow the link to the SpeechVoiceSpeakFlags info. You will find
that in addition to just speaking passed in text that can also do much more
some of the more interesting flags are;
• Pass in a file name and speak the text in the file. (SVSFIsFilename)
• Make the function either return immediately (asynchronously) or only after
the synthesis is complete(synchronously). If you speak asynchronously there
are events available to fire when the speech is done. (SVSFlagsAsync)
• Embed flags in the text that can control various aspects of the synthesis
like pitch, rate, emphasis, and much more (see the included White Paper
titled “XML TTS Tutorial”). I found this feature a bit addicting as I
attempted to make the synthesized voice sing.( SVSFIsXML)
One interesting thing I found (but not documented) was that you can speak a
web sites title by setting the flag to SVSFIsFilenam and passing a URL.
If you are connected to the internet, try replacing the speak line in the
sample line with
And run it.
Even more bizarre is you can use the speak method to play wav files. Try
SpVoice1.Speak('C:\WINNT\MEDIA\Windows Logon Sound.wav', SVSFIsFilename);
There’s a lot more to SAPI then text to speech and there’s more to text to
speech then what I’ve covered here. Hopefully this will be the first of a
number of articles on SAPI but I’ll only do them if you’re interested so
please be sure to comment. Also I’m completely open to suggestions on what
you’d like to see next (if anything at all).
If you want to talk privately I’m at email@example.com.}