Unity之Microphone如何实现录音和播放

前言

我们项目最近要做一个聊天系统，我们使用的是tencent的IM.sdk。其中里面涉及一个语音聊天，im.sdk中支持传输语音文件，但是语音文件需要我们自己录制，我看了IM.sdk的源码，里面是原生代码实现的录音和播放，但是我们用unity的话，其实官方 已经给我们带了一个microphone类，类实现麦克风的使用。所以下面就是一个简单粗暴的录音，存储，播放 的一个小demo。

数据转化

unity的录音数据使用float[]来存储，但是我们的文件系统使用的是byte[]类存储，所以我们需要做一个数据的转化函数。

• float2byte函数

    byte[] float2byte(float[] floats)
    {
    
    
        byte[] outData = new byte[floats.Length * 2];
        int reScaleFactor = 32767;

        for (int i = 0; i < floats.Length; i++)
        {
    
    
            short tempShort = (short) (floats[i] * reScaleFactor);
            byte[] tempData = BitConverter.GetBytes(tempShort);

            outData[i * 2] = tempData[0];
            outData[i * 2 + 1] = tempData[1];
        }

        return outData;
    }

• byte2float函数

    float[] byte2float(byte[] bytes)
    {
    
    
        float reScaleFactor = 32768.0f;
        float[] data = new float[bytes.Length / 2];
        for (int i = 0; i < bytes.Length; i += 2)
        {
    
    
            short s;
            if (BitConverter.IsLittleEndian) //小端和大端顺序要调整
                s = (short) ((bytes[i + 1] << 8) | bytes[i]);
            else
                s = (short) ((bytes[i] << 8) | bytes[i + 1]);
            // convert to range from -1 to (just below) 1
            data[i / 2] = s / reScaleFactor;
        }

完整代码

using System;
using System.Collections;
using UnityEngine;

public class MicrophoneInput : MonoSingleton<MicrophoneInput>
{
    protected AudioSource audioSource;
    public int lengthSec = 10;
    public int frequency = 44100;

    void Awake()
    {
        audioSource = this.GetComponent<AudioSource>();
    }

    public IEnumerator RequestMicrophoneAuth()
    {
        yield return Application.RequestUserAuthorization(UserAuthorization.Microphone);
    }

    public void StartRecord()
    {
        Debug.Log("开始录音");

        audioSource.Stop();
        audioSource.loop = false;
        audioSource.mute = true;
        audioSource.clip = Microphone.Start(null, false, 10, 44100);
        audioSource.Play();
    }

    public int StopRecord()
    {
        int length = Microphone.GetPosition(null);
        Microphone.End(null);
        audioSource.Stop();
        return length;
    }

    public void SaveAudioFile(string filePath, int length)
    {
        if (Microphone.IsRecording(null))
            return;

        byte[] data = GetClipData(audioSource, length);
        if (data == null)
        {
            return;
        }

        FileUtility.SafeWriteAllBytes(filePath, data);
        string infoLog = "total length:" + data.Length + " time:" + audioSource.time;
        Debug.Log(infoLog);
    }

    public void ReadAudioFile(string filePath)
    {
        byte[] bytes = FileUtility.SafeReadAllBytes(filePath);
        float[] samples = byte2float(bytes);

        var clip = audioSource.clip;
        audioSource.Stop();
        audioSource.clip = AudioClip.Create(clip.name, samples.Length, clip.channels, clip.frequency, false);
        audioSource.clip.SetData(samples, 0);
        audioSource.mute = false;
        audioSource.Play();
    }

    byte[] GetClipData(AudioSource source, int length)
    {
        if (length < 10)
        {
            Debug.Log("录音文件太短");
            return null;
        }

        float[] samples = new float[length];
        source.clip.GetData(samples, 0);

        byte[] outData = float2byte(samples);
        return outData;
    }

    byte[] float2byte(float[] floats)
    {
        byte[] outData = new byte[floats.Length * 2];
        int reScaleFactor = 32767;

        for (int i = 0; i < floats.Length; i++)
        {
            short tempShort = (short) (floats[i] * reScaleFactor);
            byte[] tempData = BitConverter.GetBytes(tempShort);

            outData[i * 2] = tempData[0];
            outData[i * 2 + 1] = tempData[1];
        }

        return outData;
    }

    float[] byte2float(byte[] bytes)
    {
        float reScaleFactor = 32768.0f;
        float[] data = new float[bytes.Length / 2];
        for (int i = 0; i < bytes.Length; i += 2)
        {
            short s;
            if (BitConverter.IsLittleEndian) //小端和大端顺序要调整
                s = (short) ((bytes[i + 1] << 8) | bytes[i]);
            else
                s = (short) ((bytes[i] << 8) | bytes[i + 1]);
            // convert to range from -1 to (just below) 1
            data[i / 2] = s / reScaleFactor;
        }

        return data;
    }
}

示例demo

using UnityEngine;
using UnityEngine.UI;

public class MicroTest : MonoBehaviour
{
    public Button startBtn;
    public Button stopBtn;
    
    void Awake()
    {
        startBtn.onClick.AddListener(this.OnStartClick);
        stopBtn.onClick.AddListener(this.OnStopClick);
    }

    /// <summary>
    /// 开始录制
    /// </summary>
    void OnStartClick()
    {
        Debug.Log("OnStartClick");
        
        if (!Application.HasUserAuthorization(UserAuthorization.Microphone))
        {
            StartCoroutine(MicrophoneInput.Instance.RequestMicrophoneAuth());
            return;
        }
        
        MicrophoneInput.Instance.StartRecord();
    }
    
    /// <summary>
    /// 停止录制
    /// </summary>
    private void OnStopClick()
    {
        Debug.Log("OnStopClick");

        int length = MicrophoneInput.Instance.StopRecord();
        var path = Application.persistentDataPath + "/audios/micro.m4a";
        MicrophoneInput.Instance.SaveAudioFile(path, length);

        PlayAudio();
    }

    /// <summary>
    /// 播放录音
    /// </summary>
    private void PlayAudio()
    {
        var path = Application.persistentDataPath + "/audios/micro.m4a";
        //读取本地文件播放
        MicrophoneInput.Instance.ReadAudioFile(path);
    }

}