Google speech to text API in C#

Question

My program get a correct respon from google when the flac file recorded manual by using windows\'s sound recorder and convert it using a software converter.
But when I

Answer 1

I was also having the same issue but came up with a neat solution. I used Fiddler (http://www.telerik.com/fiddler/) to figure out how Chrome does the speech recognition and then created some code to emulate chrome sending the request. This approach uses a different URI and there is also a 16-character value called pair which is different for each request. I use a simple random value generator function to create one for the request and I also changed the output value to 'json'.

Note: The result can sometimes be empty as in your case above but there's also another json object in the response that contains the alternatives.

    private void GoogleSpeechToText()
    {
        string uri = "https://www.google.com/speech-api/full-duplex/v1/up?output=json&key=AIzaSyBOti4mM-6x9WDnZIjIeyEU21OpBXqWBgw&pair=" + GenerateUnique(16) + "&lang=en-US&pFilter=2&maxAlternatives=10&client=chromium";
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
        request.Timeout = 10000;
        request.Method = "POST";
        request.Host = "www.google.com";            
        request.KeepAlive = true;
        request.SendChunked = true;
        request.ContentType = "audio/x-flac; rate=16000";
        request.Headers.Set(HttpRequestHeader.AcceptLanguage, "en-GB,en-US;q=0.8,en;q=0.6");
        request.UserAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Safari/537.36";

        string path = @"C:\TestFolder\test_audio.flac";     
        FileInfo fInfo = new FileInfo(path);
        var numBytes = fInfo.Length;
        byte[] data;

        using (FileStream fStream = new FileStream(path, FileMode.Open, FileAccess.Read))
        {
            data = new Byte[numBytes];
            fStream.Read(data, 0, (int) numBytes);
            fStream.Close();
        }

        using (Stream reqStream = request.GetRequestStream())
            reqStream.Write(data, 0, data.Length);

        try
        {
            WebResponse response = request.GetResponse();
            Stream respStream = response.GetResponseStream();

            if(response.ContentType == "application/json; charset=utf-8")
            {                    
                using (var sr = new StreamReader(respStream))
                {
                    var res = sr.ReadToEnd();
                    textBox1.Text = res;                        
                }
            }
        }
        catch (Exception ex) { MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK); }            
    }

    private string GenerateUnique(int length)
    {
        string[] LETTERS = new string[] { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };
        string[] DIGITS = new string[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
        string buffer = "";
        Random random = new Random();

        for(int i = 0; i < length; i++)
        {                
            int rnd = random.Next(2);
            if (rnd == 1)
                buffer += LETTERS[random.Next(LETTERS.Length)];
            else
                buffer += DIGITS[random.Next(DIGITS.Length)];
        }
        return buffer;
    }