Azure TTS neural voice audio file is created abnormally in 1 byte size - azure

Question

Azure TTS standard voice audio files are generated normally. However, for neural voice, the audio file is generated abnormally with the size of 1 byte. The code is below.
C# code
public static async Task SynthesizeAudioAsync()
{
var config = SpeechConfig.FromSubscription("xxxxxxxxxKey", "xxxxxxxRegion");
using var synthesizer = new SpeechSynthesizer(config, null);
var ssml = File.ReadAllText("C:/ssml.xml");
var result = await synthesizer.SpeakSsmlAsync(ssml);
​ using var stream = AudioDataStream.FromResult(result);
await stream.SaveToWaveFileAsync("C:/file.wav");
}
ssml.xml - The file below, set to standard voice, works fine.
<speak version="1.0" xmlns="https://www.w3.org/2001/10/synthesis" xml:lang="en-US">
<voice name="en-GB-George-Apollo">
When you're on the motorway, it's a good idea to use a sat-nav.
</voice>
</speak>
ssml.xml - However, the following file set for neural voice does not work, and an empty sound source file is created.
<speak version="1.0" xmlns="https://www.w3.org/2001/10/synthesis" xml:lang="en-US">
<voice name="en-US-AriaNeural">
When you're on the motorway, it's a good idea to use a sat-nav.
</voice>
</speak>

Answer 1

Looking at the behavior you have described due to some issues, the Speech service has returned no audio bytes.
I have checked the SSML file at my end it works completely fine i.e. there is no issues with the SSML.
As a next step to the solution, I would recommend you to add error handling code to give better picture of the error and take the action accordingly :
var config = SpeechConfig.FromSubscription("xxxxxxxxxKey", "xxxxxxxRegion");
using var synthesizer = new SpeechSynthesizer(config, null);
var ssml = File.ReadAllText("C:/ssml.xml");
var result = await synthesizer.SpeakSsmlAsync(ssml);
if (result.Reason == ResultReason.Canceled)
{
var cancellation = SpeechSynthesisCancellationDetails.FromResult(result);
Console.WriteLine($"CANCELED: Reason={cancellation.Reason}");
if (result.Reason == ResultReason.SynthesizingAudioCompleted)
{
Console.WriteLine ("No error ")
using var stream = AudioDataStream.FromResult(result);
await stream.SaveToWaveFileAsync("C:/file.wav");
}
else if (cancellation.Reason == CancellationReason.Error)
{
{
Console.WriteLine($"CANCELED: ErrorCode={cancellation.ErrorCode}");
Console.WriteLine($"CANCELED: ErrorDetails=[{cancellation.ErrorDetails}]");
}
}
The above piece of modification will provide friendly error message on the console app.
Note : If you are not using the console app, you will have modify the code.
Sample output :
This is just a sample output. the error you might see would be different.