export MP3 from unity audioclip

AudioClipToMP3.cs

// export MP3 from unity audioclip
// https://forum.unity.com/threads/exporting-mp3-file-from-audioclip.697175/

/*                    GNU GENERAL PUBLIC LICENSE
                           Version 3, 29 June 2007
     
    Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
    Everyone is permitted to copy and distribute verbatim copies
    of this license document, but changing it is not allowed.
     
    */
     
    /*---------------------- BeatUp (C) 2016-------------------- */
     
     
    using UnityEngine;
    using System.Collections;
    using System.Collections.Generic;
    using System.IO;
    using System;
    using NAudio.Wave;
    using NAudio.Lame;
     
    public static class EncodeMP3
    {
     
     
        public static void convert (AudioClip clip, string path, int bitRate)
        {
     
            if (!path.EndsWith (".mp3"))
                path = path + ".mp3";
           
            ConvertAndWrite (clip, path, bitRate);
     
        }
     
     
        //  derived from Gregorio Zanon's script
        private static void ConvertAndWrite (AudioClip clip, string path, int bitRate)
        {
     
            float[] samples = new float[clip.samples * clip.channels];
     
            clip.GetData (samples, 0);
     
            Debug.Log(samples.Length);
     
            Int16[] intData = new Int16[samples.Length];
            //converting in 2 float[] steps to Int16[], //then Int16[] to Byte[]
     
            Byte[] bytesData = new Byte[samples.Length * 2];
            //bytesData array is twice the size of
            //dataSource array because a float converted in Int16 is 2 bytes.
     
            float rescaleFactor = 32767; //to convert float to Int16
     
            for (int i = 0; i < samples.Length; i++) {
                intData[i] = (short)(samples[i] * rescaleFactor);
                Byte[] byteArr = new Byte[2];
                byteArr = BitConverter.GetBytes(intData[i]);
                byteArr.CopyTo(bytesData, i * 2);
            }
     
            File.WriteAllBytes (path, ConvertWavToMp3 (bytesData, bitRate));
        }
     
        public static byte[] GetClipData(AudioClip _clip)
        {
            //Get data
            float[] floatData = new float[_clip.samples * _clip.channels];
            _clip.GetData(floatData, 0);
     
            //convert to byte array
            byte[] byteData = new byte[floatData.Length * 4];
            Buffer.BlockCopy(floatData, 0, byteData, 0, byteData.Length);
     
            return (byteData);
        }
     
     
     
        private static byte[] ConvertWavToMp3 (byte[] bytes, int bitRate)
        {
     
            var retMs = new MemoryStream ();
            var ms = new MemoryStream (bytes);
            var rdr = new RawSourceWaveStream (ms, new WaveFormat ());
            var wtr = new LameMP3FileWriter (retMs, rdr.WaveFormat, bitRate);
     
            rdr.CopyTo (wtr);
            return retMs.ToArray ();
     
     
     
        }
    }