使用SpeechLib托管问题

Question

Hi I'm developing a web project with c# and using VS2010. I'm using the SpeechLib, that converts text to speech. Locally in my computer all works well, but when hosting the web page the page doesn't works and the error 500 is outputted.

As stated in another old post ( link ), the problem seems to be that this library tries to write a temporary file in a folder without the necessary permissions. The problem but was not solved.

How can I solve this problem? Thanks!

Answer 1

One way to get around disk permission issue is to not save the audio to disk. To do this, you would convert the output to a stream object, which can be returned via a web page, HTTP handler, or MVC action. Unfortunately, the "SetOutputToAudioStream" only returns raw PCM audio.

In order to output other encodings like µ-law (mu-law, u-law, ulaw), you have to gain access to a non-public SetOutputStream method by using reflection. Below is a code snippet that accomplishes this and returns a byte array:

using System.Reflection;

/* Beginning Code */

byte outputWavBytes;

MemoryStream outputWav = new MemoryStream()
using (SpeechSynthesizer synth = new SpeechSynthesizer())
{
    var mi = synth.GetType().GetMethod("SetOutputStream", BindingFlags.Instance | BindingFlags.NonPublic);
    var fmt = new SpeechAudioFormatInfo(EncodingFormat.ULaw, 8000, 8, 1, 20, 2, null)
    mi.Invoke(synth, new object[] { outputWav, fmt, true, true });
    synth.Speak("This is a test to stream a different encoding.");
    outputWav.Seek(0, SeekOrigin.Begin);
    outputWavBytes = outputWav.GetBuffer();
}



/* End Code */