Unity3D: script to save an AudioClip as a .wav file. https://gist.github.com/darktable/2317063 http://stackoverflow.com/questions/36791499/how-to-convert-a-wav-audio-to-mp3-ogg-on-ios

SavWav.cs

//	Copyright (c) 2012 Calvin Rien
//        http://the.darktable.com
//
//	This software is provided 'as-is', without any express or implied warranty. In
//	no event will the authors be held liable for any damages arising from the use
//	of this software.
//
//	Permission is granted to anyone to use this software for any purpose,
//	including commercial applications, and to alter it and redistribute it freely,
//	subject to the following restrictions:
//
//	1. The origin of this software must not be misrepresented; you must not claim
//	that you wrote the original software. If you use this software in a product,
//	an acknowledgment in the product documentation would be appreciated but is not
//	required.
//
//	2. Altered source versions must be plainly marked as such, and must not be
//	misrepresented as being the original software.
//
//	3. This notice may not be removed or altered from any source distribution.
//
//  =============================================================================
//
//  derived from Gregorio Zanon's script
//  http://forum.unity3d.com/threads/119295-Writing-AudioListener.GetOutputData-to-wav-problem?p=806734&viewfull=1#post806734

using System;
using System.IO;
using UnityEngine;
using System.Collections.Generic;

public static class SavWav {

	const int HEADER_SIZE = 44;

	public static bool Save(string filename, AudioClip clip) {
		if (!filename.ToLower().EndsWith(".wav")) {
			filename += ".wav";
		}

		var filepath = Path.Combine(Application.persistentDataPath, filename);

		Debug.Log(filepath);

		// Make sure directory exists if user is saving to sub dir.
		Directory.CreateDirectory(Path.GetDirectoryName(filepath));

		using (var fileStream = CreateEmpty(filepath)) {

			ConvertAndWrite(fileStream, clip);

			WriteHeader(fileStream, clip);
		}

		return true; // TODO: return false if there's a failure saving the file
	}

	public static AudioClip TrimSilence(AudioClip clip, float min) {
		var samples = new float[clip.samples];

		clip.GetData(samples, 0);

		return TrimSilence(new List<float>(samples), min, clip.channels, clip.frequency);
	}

	public static AudioClip TrimSilence(List<float> samples, float min, int channels, int hz) {
		return TrimSilence(samples, min, channels, hz, false, false);
	}

	public static AudioClip TrimSilence(List<float> samples, float min, int channels, int hz, bool _3D, bool stream) {
		int i;

		for (i=0; i<samples.Count; i++) {
			if (Mathf.Abs(samples[i]) > min) {
				break;
			}
		}

		samples.RemoveRange(0, i);

		for (i=samples.Count - 1; i>0; i--) {
			if (Mathf.Abs(samples[i]) > min) {
				break;
			}
		}

		samples.RemoveRange(i, samples.Count - i);

		var clip = AudioClip.Create("TempClip", samples.Count, channels, hz, _3D, stream);

		clip.SetData(samples.ToArray(), 0);

		return clip;
	}

	static FileStream CreateEmpty(string filepath) {
		var fileStream = new FileStream(filepath, FileMode.Create);
	    byte emptyByte = new byte();

	    for(int i = 0; i < HEADER_SIZE; i++) //preparing the header
	    {
	        fileStream.WriteByte(emptyByte);
	    }

		return fileStream;
	}

	static void ConvertAndWrite(FileStream fileStream, AudioClip clip) {

		var samples = new float[clip.samples];

		clip.GetData(samples, 0);

		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.

		int 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);
		}

		fileStream.Write(bytesData, 0, bytesData.Length);
	}

	static void WriteHeader(FileStream fileStream, AudioClip clip) {

		var hz = clip.frequency;
		var channels = clip.channels;
		var samples = clip.samples;

		fileStream.Seek(0, SeekOrigin.Begin);

		Byte[] riff = System.Text.Encoding.UTF8.GetBytes("RIFF");
		fileStream.Write(riff, 0, 4);

		Byte[] chunkSize = BitConverter.GetBytes(fileStream.Length - 8);
		fileStream.Write(chunkSize, 0, 4);

		Byte[] wave = System.Text.Encoding.UTF8.GetBytes("WAVE");
		fileStream.Write(wave, 0, 4);

		Byte[] fmt = System.Text.Encoding.UTF8.GetBytes("fmt ");
		fileStream.Write(fmt, 0, 4);

		Byte[] subChunk1 = BitConverter.GetBytes(16);
		fileStream.Write(subChunk1, 0, 4);

		UInt16 two = 2;
		UInt16 one = 1;

		Byte[] audioFormat = BitConverter.GetBytes(one);
		fileStream.Write(audioFormat, 0, 2);

		Byte[] numChannels = BitConverter.GetBytes(channels);
		fileStream.Write(numChannels, 0, 2);

		Byte[] sampleRate = BitConverter.GetBytes(hz);
		fileStream.Write(sampleRate, 0, 4);

		Byte[] byteRate = BitConverter.GetBytes(hz * channels * 2); // sampleRate * bytesPerSample*number of channels, here 44100*2*2
		fileStream.Write(byteRate, 0, 4);

		UInt16 blockAlign = (ushort) (channels * 2);
		fileStream.Write(BitConverter.GetBytes(blockAlign), 0, 2);

		UInt16 bps = 16;
		Byte[] bitsPerSample = BitConverter.GetBytes(bps);
		fileStream.Write(bitsPerSample, 0, 2);

		Byte[] datastring = System.Text.Encoding.UTF8.GetBytes("data");
		fileStream.Write(datastring, 0, 4);

		Byte[] subChunk2 = BitConverter.GetBytes(samples * channels * 2);
		fileStream.Write(subChunk2, 0, 4);

//		fileStream.Close();
	}
}

SavWav_001.cs

//
//	Script altered Bt Timthy White@Funire in 20160425
//	
//Copyright (c) 2012 Calvin Rien
//        http://the.darktable.com
//
//	This software is provided 'as-is', without any express or implied warranty. In
//	no event will the authors be held liable for any damages arising from the use
//	of this software.
//
//	Permission is granted to anyone to use this software for any purpose,
//	including commercial applications, and to alter it and redistribute it freely,
//	subject to the following restrictions:
//
//	1. The origin of this software must not be misrepresented; you must not claim
//	that you wrote the original software. If you use this software in a product,
//	an acknowledgment in the product documentation would be appreciated but is not
//	required.
//
//	2. Altered source versions must be plainly marked as such, and must not be
//	misrepresented as being the original software.
//
//	3. This notice may not be removed or altered from any source distribution.
//
//  =============================================================================
//
//  derived from Gregorio Zanon's script
//  http://forum.unity3d.com/threads/119295-Writing-AudioListener.GetOutputData-to-wav-problem?p=806734&viewfull=1#post806734
//


using System;
using System.IO;
using UnityEngine;
using System.Collections.Generic;
using System.Threading;

public static class SavWav {

	const int HEADER_SIZE = 44;
	//static Thread savingThread;

	/// <summary>
	/// Get The Paths for different platforms. Input a name and return a path with the name
	/// </summary>
	/// <returns>The for documents file.</returns>
	/// <param name="filename">Filename.</param>
	static string pathForDocumentsFile( string filename )
	{
		if (Application.platform == RuntimePlatform.IPhonePlayer)
		{
			string path = Application.dataPath.Substring( 0, Application.dataPath.Length - 5 );
			path = path.Substring( 0, path.LastIndexOf( '/' ) );
			return Path.Combine( Path.Combine( path, "Documents" ), filename );
		}

		else if(Application.platform == RuntimePlatform.Android)
		{
			string path = Application.persistentDataPath;
			path = path.Substring(0, path.LastIndexOf( '/' ) );
			//return Path.Combine (path, filename);
			return Path.Combine("/mnt/sdcard", filename);
		}

		else
		{
			string path = Application.persistentDataPath;
			//path = path.Substring(0, path.LastIndexOf( '/' ) );
			return Path.Combine (path, filename);
		}
	} 



	static void SaveToDisk(){



	}

	public static string Save(string filename, AudioClip clip) {
		if (!filename.ToLower().EndsWith(".wav")) {
			filename += ".wav";
		}



		var filepath =pathForDocumentsFile( filename); 

		Debug.Log(filepath);

		// Make sure directory exists if user is saving to sub dir.
		Directory.CreateDirectory(Path.GetDirectoryName(filepath));

		using (var fileStream = CreateEmptyFileStream(filepath)) {

//			savingThread=new Thread(()=>{
//
//				Debug.Log("thread run");
//
//				ConvertAndWrite(fileStream,clip.samples);
//			});
//			savingThread.Start();



				//ConvertAndWrite(fileStream, clip);

			ConvertAndWrite(fileStream,clip);
			WriteHeader(fileStream, clip);

		}

		return filepath; // TODO: return false if there's a failure saving the file
	}



	public static AudioClip TrimSilence(AudioClip clip, float min) {


		var samples = new float[clip.samples];

		clip.GetData(samples, 0);

		return TrimSilence(new List<float>(samples), min, clip.channels, clip.frequency);
	}


	public static AudioClip TrimSilence(List<float> samples, float min, int channels, int hz) {
		return TrimSilence(samples, min, channels, hz, false, false);
	}


	/// <summary>
	/// Trims the silence. Remove the invalid audio data from the start and the end to the recording sound.
	/// </summary>
	/// <returns>Audio Clip.</returns>
	/// <param name="samples">Audio Clip Samples.</param>
	/// <param name="min">the audio threshold.</param>
	/// <param name="channels">Channels.</param>
	/// <param name="hz">Hz.</param>
	/// <param name="_3D">If set to <c>true</c> 3.</param>
	/// <param name="stream">If set to <c>true</c> stream.</param>
	public static AudioClip TrimSilence(List<float> samples, float min, int channels, int hz, bool _3D, bool stream) {
		int i;

		for (i=0; i<samples.Count; i++) {
			if (Mathf.Abs(samples[i]) > min) {
				break;
			}
		}

		samples.RemoveRange(0, i);

		for (i=samples.Count - 1; i>0; i--) {
			if (Mathf.Abs(samples[i]) > min) {
				break;
			}
		}

		samples.RemoveRange(i, samples.Count - i);

		var clip = AudioClip.Create("TempClip", samples.Count, channels, hz, _3D, stream);

		clip.SetData(samples.ToArray(), 0);

		return clip;
	}

	static FileStream CreateEmptyFileStream(string filepath) {
		var fileStream = new FileStream(filepath, FileMode.Create);
		byte emptyByte = new byte();

		for(int i = 0; i < HEADER_SIZE; i++) //preparing the header
		{
			fileStream.WriteByte(emptyByte);
		}

		return fileStream;
	}

	static void ConvertAndWrite(FileStream fileStream, AudioClip clip) {



		var samples = new float[clip.samples*clip.channels];
		Debug.Log(samples);
		clip.GetData(samples, 0);
		Debug.Log(samples);

		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.

		int 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);
		}

		fileStream.Write(bytesData, 0, bytesData.Length);
	}

	static void ConvertAndWrite(FileStream fileStream, int clipSamples	) {

		var samples = new float[clipSamples];

		//clip.GetData(samples, 0);


		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.

		int 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);
		}

		fileStream.Write(bytesData, 0, bytesData.Length);
	}


	static void WriteHeader(FileStream fileStream, AudioClip clip) {

		var hz = clip.frequency;
		var channels = clip.channels;
		var samples = clip.samples;

		fileStream.Seek(0, SeekOrigin.Begin);

		Byte[] riff = System.Text.Encoding.UTF8.GetBytes("RIFF");
		fileStream.Write(riff, 0, 4);

		Byte[] chunkSize = BitConverter.GetBytes(fileStream.Length - 8);
		fileStream.Write(chunkSize, 0, 4);

		Byte[] wave = System.Text.Encoding.UTF8.GetBytes("WAVE");
		fileStream.Write(wave, 0, 4);

		Byte[] fmt = System.Text.Encoding.UTF8.GetBytes("fmt ");
		fileStream.Write(fmt, 0, 4);

		Byte[] subChunk1 = BitConverter.GetBytes(16);
		fileStream.Write(subChunk1, 0, 4);

		UInt16 two = 2;
		UInt16 one = 1;

		Byte[] audioFormat = BitConverter.GetBytes(one);
		fileStream.Write(audioFormat, 0, 2);

		Byte[] numChannels = BitConverter.GetBytes(channels);
		fileStream.Write(numChannels, 0, 2);

		Byte[] sampleRate = BitConverter.GetBytes(hz);
		fileStream.Write(sampleRate, 0, 4);

		Byte[] byteRate = BitConverter.GetBytes(hz * channels * 2); // sampleRate * bytesPerSample*number of channels, here 44100*2*2
		fileStream.Write(byteRate, 0, 4);

		UInt16 blockAlign = (ushort) (channels * 2);
		fileStream.Write(BitConverter.GetBytes(blockAlign), 0, 2);

		UInt16 bps = 16;
		Byte[] bitsPerSample = BitConverter.GetBytes(bps);
		fileStream.Write(bitsPerSample, 0, 2);

		Byte[] datastring = System.Text.Encoding.UTF8.GetBytes("data");
		fileStream.Write(datastring, 0, 4);

		Byte[] subChunk2 = BitConverter.GetBytes(samples * channels * 2);
		fileStream.Write(subChunk2, 0, 4);

		//		fileStream.Close();
	}
}