Creating a ASP.NET application converting text to speech

Question

I seek some insight in creating an application that converts text to speech in ASP.NET. From my initial research, it appears that:

1. MS SAPI requires the clie

Answer 1

By default, ASP.Net applications don't run with sufficient permissions to access Speech Synthesis, and attempting to run Larsenal's code will fail with a security error.

I was able to get around this in an app by having a separate WCF service running on the server, as a regular Windows Service. The ASP.Net application then communicated with that service. That service just wrapped Larsenal's code, returning an array of bytes, given a string of text.

Also, one megabyte of text? That's a good-sized novel.

Edit, 11-12-09, answering some comments:

System.Speech can either return an array of bytes, or save to a wav file, which you can then feed to a media player embedded on the user's page. When I built my talking web page, it worked like this:

1) Page.aspx includes an 'embed' tag that puts a Windows Media Player on the page. The source is "PlayText.aspx?Textid=whatever".
2) PlayText.aspx loads the appropriate text, and communicates (via WCF) to the speechreader service, handing it the text to read.
3) The Speechreader service creates a MemoryStream and calls SpeechSynthesiser.SetOutputToWaveStream, and then returns the stream as a single array of bytes. This array is Response.Write()-ed to the client.

Here's the meat of the SpeechReader service:

    byte[] ITextReader.SpeakText(string text)
    {
        using (SpeechSynthesizer s = new SpeechSynthesizer())
        {
            using (MemoryStream ms = new MemoryStream())
            {
                s.SetOutputToWaveStream(ms);
                s.Speak(text);
                return ms.GetBuffer();
            }
        }
    }

I'm pretty sure that on the back end, this returns an enormous XML array-of-bytes, and is horribly inefficient. I just did it as a proof of concept, and so didn't research that. If you intend to use this in production, make sure that it's not internally returning something like this:

<byte>23</byte>
<byte>42</byte>
<byte>117</byte>
...

Answer 2

With the SpeechSynthesizer, you can output to a WAV file. You could then have a secondary process compress or convert to another format if needed. All this could be done on the server and then sent up through the browser.

This CodeProject article is a good introduction to .NET Speech Synthesis.

If you want to see how it performs with a LOT of text.... Add a reference to System.Speech and then use the following as a starting point:

using System;
using System.Speech.Synthesis;

namespace SpeakToMe
{
    class Program
    {
        static void Main(string[] args)
        {
            SpeechSynthesizer synth = new SpeechSynthesizer();
            synth.SetOutputToWaveFile("c:\\test.wav");
            synth.Speak("Hello, world.");
            synth.SetOutputToDefaultAudioDevice();

            Console.ReadLine();
        }
    }
}

A quick test on a file of 44,700 words (238KB) on my relatively fast machine...

• Completed in 55 seconds
• Generated a 626 MB WAV file

Answer 3

I searched for "Convert Text Into Speech In Asp.Net" in Google and found a very nice and usefull link:

http://codeprojectdownload.com/asp-net-2/convert-text-into-speech-in-asp-net/#.T0ScXIfXDZE

It may also be useful to you.

Answer 4

I achieved this by using codeBehind to run a javascript function that runs the text-to-speech command:

codeBehind:

Page.ClientScript.RegisterStartupScript(
GetType(), 
"anythingHere", 
"nameOfFunction();", 
true);

javascript:

<script>
  function nameOfFunction()
    {//start
       var msg = new SpeechSynthesisUtterance('READ ME!');
       window.speechSynthesis.speak(msg);
    }//end
</script>

Answer 5

I wrote an article on this on my blog: http://weblogs.asp.net/ricardoperes/archive/2014/04/08/speech-synthesis-with-asp-net-and-html5.aspx. I used AJAX and Data URIs to send voice data back and forth between the client and the server.