C#（WPF）通过WebAPI方式调用科大讯飞实现语音识别_.net webapi语音播报

作者：从前慢现在也慢 | 2024-05-05 16:00:22

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.net webapi语音播报

参考连接：

语音听写（流式版）WebAPI 文档 | 讯飞开放平台文档中心 (xfyun.cn)

http://t.csdnimg.cn/4zSMA

http://t.csdnimg.cn/1IXfO

在用WPF做上位机的时候需要用到科大讯飞的语音识别功能，看了看官方文档在Windows上想要实现语音识别可以通过WebAPI或者SDK的方式实现。

在网上对比了两种方法，SDK好像不能直接用到C#上面，而且还要往文件里引入好几个库，本着偷懒的想法就选择了WebAPI的方法，相对来说会简洁一点。

使用的是.NET Framework 4.7.2

如果将修改成以下参数，识别速度会大大加快但是没有经过大量测试不能保证稳定性。

int frameSize = 6400;
int intervel = 10;

3.14更新：

主要是在接收返回结果的函数中，对是否接收到服务器的结果全部返回标识做了判断，并断开与服务器的连接


using HandyControl.Controls;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.WebSockets;
using System.Security.Cryptography;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
 
namespace HandyControlTest
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : System.Windows.Window
    {
        recorder r = new recorder();
        public MainWindow()
        {
            InitializeComponent();
        }
 
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            r.SendFileToWebSocket();
            r.receiveMessage();
        }
    }
}
 
class recorder
{
    private string _appID = "6f28cdb3";
    private string _apiSecret = "Mzc3OWJjYjQxYjI5YzVhNWMwYzdiNmFk";
    private string _apiKey = "bf7d03b453328d790a0d2efabe47a1db";
    private string _wss = "wss://iat-api.xfyun.cn/v2/iat";
    private string _host = "iat-api.xfyun.cn";
    private string _request_line = "GET /v2/iat HTTP/1.1";
    private bool _isConnected = false;//连接服务器标志位
    private bool _isSendDone = false;//已经完成发送
    private WebSocket _ws;
 
    //创建url
    private string GetUrl()
    {
        string date = DateTime.Now.ToString("R");
        string signature_origin = $"host: {_host}\ndate: {date}\n{_request_line}";
        HMACSHA256 mac = new HMACSHA256(Encoding.UTF8.GetBytes(_apiSecret));
        string signature = Convert.ToBase64String(mac.ComputeHash(Encoding.UTF8.GetBytes(signature_origin)));
        string authorization_origin = $"api_key=\"{_apiKey}\",algorithm=\"hmac-sha256\",headers=\"host date request-line\",signature=\"{signature}\"";
        string authorization = Convert.ToBase64String(Encoding.UTF8.GetBytes(authorization_origin));
        string url = $"{_wss}?authorization={authorization}&date={date}&host={_host}";
        return url;
    }
 
    //连接WebSocket服务器
    private async void ConnectWebSocket()
    {
        try
        {
            Uri url = new Uri(this.GetUrl());
            ClientWebSocket webSocket = new ClientWebSocket();
            CancellationToken ct = new CancellationToken();
            await webSocket.ConnectAsync(url, ct);
            _isConnected = true;
            _ws = webSocket;
        }
        catch (Exception ex)
        {
            System.Windows.MessageBox.Show(ex.Message);
        }
    }
 
    //发送音频至服务器
    public async void SendFileToWebSocket()
    {
        int frameSize = 6400;//每次发送音频字节数6400B
        int intervel = 5;//每次发送音频间隔5ms
        int pcmCount = 0;//记录音频已发送的大小
        int pcmSize = 0;//剩余音频大小
        int status = 0;//音频的发送状态;0：第一帧；1：继续帧；2：最后一帧
        string filePath = "E:\\SystemData\\desktop\\recorded.wav";//录音文件路径
 
        ConnectWebSocket();
 
        try
        {
            while (!_isConnected)
            {
                await Task.Delay(intervel);//异步等待服务器连接
            }
 
            byte[] arr = File.ReadAllBytes(filePath);//读取文件所有字节
            if (arr == null)
            {
                return;
            }
 
            pcmSize = arr.Length;//获取音频总长
            while (true)
            {
                if (pcmSize <= frameSize)//若剩余音频小于等于1280B，则视为最后帧发送
                {
                    frameSize = pcmSize;
                    status = 2;
                    if (frameSize <= 0)
                        break;
                }
                byte[] buffer = new byte[frameSize];
                Array.Copy(arr, pcmCount, buffer, 0, frameSize);
                pcmCount += frameSize;
                pcmSize -= frameSize;
                switch (status)
                {
                    case 0:
                        onSend(0, Convert.ToBase64String(buffer));
                        status = 1;
                        break;
 
                    case 1:
                        onSend(1, Convert.ToBase64String(buffer));
                        break;
 
                    case 2:
                        onSend(1, Convert.ToBase64String(buffer));
                        onSend(2, null);//告诉服务器已经发送结束，本应该需要隔40ms再发送
                        _isSendDone = true;
                        break;
                }
                await Task.Delay(intervel);//延时40ms
            }
        }
        catch (Exception e)
        {
            System.Windows.MessageBox.Show(e.Message);
        }
    }
 
    //每次发送数据
    //curStatus：用于记录发送过程
    //0：首次发送；1：发送中；2：结束发送
    private void onSend(int curStatus, string data)
    {
        if (curStatus == 0)
        {
            var json = new
            {
                common = new
                {
                    app_id = $"{_appID}"
                },
                business = new
                {
                    language = "zh_cn",
                    domain = "iat",
                    accent = "mandarin"
                },
                data = new
                {
                    status = 0,
                    format = "audio/L16;rate=16000",
                    encoding = "raw",
                    audio = $"{data}"
                }
            };
            string jsonStr = JsonConvert.SerializeObject(json, Formatting.Indented);
            _ws.SendAsync(new ArraySegment<byte>(Encoding.UTF8.GetBytes(jsonStr)), WebSocketMessageType.Binary, true, new CancellationToken());
        }
 
        else if (curStatus == 1)
        {
            var json = new
            {
                data = new
                {
                    status = 1,
                    format = "audio/L16;rate=16000",
                    encoding = "raw",
                    audio = $"{data}"
                }
            };
            string jsonStr = JsonConvert.SerializeObject(json, Formatting.Indented);
            _ws.SendAsync(new ArraySegment<byte>(Encoding.UTF8.GetBytes(jsonStr)), WebSocketMessageType.Binary, true, new CancellationToken());
        }
 
        else if (curStatus == 2)
        {
            var json = new
            {
                data = new
                {
                    status = 2
                }
            };
            string jsonStr = JsonConvert.SerializeObject(json, Formatting.Indented);
            _ws.SendAsync(new ArraySegment<byte>(Encoding.UTF8.GetBytes(jsonStr)), WebSocketMessageType.Binary, true, new CancellationToken());
        }
    }
 
    public async void receiveMessage()
    {
        while (!_isSendDone)
        {
            await Task.Delay(10);//异步等待服务器连接
        }
        byte[] buffer = new byte[1024];//可以给大一点，如果识别长时间音频可以会出bug
        string str = null;//拼接整句话
        while (_ws.State == WebSocketState.Open)
        {
            WebSocketReceiveResult result = await _ws.ReceiveAsync(new ArraySegment<byte>(buffer),CancellationToken.None);//等待返回结果
            if(result.MessageType == WebSocketMessageType.Text)
            {
                string jsonData = Encoding.UTF8.GetString(buffer,0,result.Count);
                var jsonObject = JsonConvert.DeserializeObject<dynamic>(jsonData);//转换为json格式
                var data = jsonObject["data"]["result"]["ws"];//提取听写结果
                foreach (var item in data)
                {
                    foreach (var item2 in item["cw"])
                    {
                        str += item2["w"];
                    } 
                }
                bool done = jsonObject["data"]["result"]["ls"];//是否完成所有返回结果的接收
                if(done)
                {
                    await _ws.CloseAsync(WebSocketCloseStatus.NormalClosure, "closing", CancellationToken.None);//断开与服务器的连接
                    _isSendDone = false;
                    _isConnected = false;
                    break;
                }
            }
        }
        HandyControl.Controls.MessageBox.Show(str);
    }
}

这是我用来实现语音识别的测试，空出来的几个参数是需要自己注册科大讯飞账号然后在控制台获取

private string _appID = ;
private string _apiSecret = ;
private string _apiKey = ;

科大讯飞对于音频有要求，具体可到官方文档查阅，我使用开源库NAudio能够录制到符合要求的音频

GitHub - naudio/NAudio: Audio and MIDI library for .NET

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