Google Cloud Streaming Speech API

I need real time speech recognition through Google Cloud Speech API. However it is still in beta version and there are not much helpful things available on the internet.

https://cloud.google.com/speech/docs/samples there are few samples available here but I don't see streaming API with C#, does that mean I cannot use C# for steaming my audio input the Google Cloud Speech API?

Anyone tried streaming audio input to the Cloud Speech API using .NET?

FYI, I cannot used normal Web Speech API available from Google. I need to use only Goolge Cloud Speech API.

Solution

You have to download the sample applications from here: https://cloud.google.com/speech/docs/samples

The you will find the Speech samples: QuickStart and Recognize.

The Recogize have a lot option, and one of them is Listen. This sample is streaming audio, and write the result to the console continuously.

The sample uses a protobuf byte stream for streaming. Here is the main part of the code:

var credential = GoogleCredential.FromFile( "privatekey.json" ).CreateScoped( SpeechClient.DefaultScopes );
var channel = new Grpc.Core.Channel( SpeechClient.DefaultEndpoint.ToString(), credential.ToChannelCredentials() );
var speech = SpeechClient.Create( channel );
var streamingCall = speech.StreamingRecognize();
// Write the initial request with the config.
await streamingCall.WriteAsync(
    new StreamingRecognizeRequest()
    {
        StreamingConfig = new StreamingRecognitionConfig()
        {
            Config = new RecognitionConfig()
            {
                Encoding =
                RecognitionConfig.Types.AudioEncoding.Linear16,
                SampleRateHertz = 16000,
                LanguageCode = "hu",
            },
            InterimResults = true,
        }
    } );

of course the language must be changed.

Then must be stream the content:

streamingCall.WriteAsync(
    new StreamingRecognizeRequest()
    {
        AudioContent = Google.Protobuf.ByteString
            .CopyFrom( args.Buffer, 0, args.BytesRecorded )
    } ).Wait();