AutoLipSyncBlendshape.cs

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

[RequireComponent (typeof (AudioSource))]
public class AutoLipSyncBlendshape : MonoBehaviour
{

  public SkinnedMeshRenderer skinnedMeshRenderer;

  public float maxWeight = 1;

  public string blendShapeName;
  private int blendShapeIndex = -1;

  private float volume;
  private float bin = 0.04f;
  private int width = 64;
  private float output;

  private float[] array;
  private AudioSource _audio;


  private void Awake ()
  {
    _audio = GetComponent <AudioSource>();
    array = new float[width];

    for (int i = 0; i < skinnedMeshRenderer.sharedMesh.blendShapeCount; i++)
    {
      if (skinnedMeshRenderer.sharedMesh.GetBlendShapeName(i) == blendShapeName) {
        blendShapeIndex = i;
      }
    }

    if (blendShapeIndex == -1) {
      Debug.LogError("No blend shape named " + blendShapeName + " was found.");
    }

  }

  private void FixedUpdate ()
  {
    if (_audio.isPlaying)
    {
      _audio.GetOutputData(array, 0);
      float num3 = 0f;
      for (int i = 0; i < width; i++)
      {
          float num4 = Mathf.Abs(array[i]);
          num3 += num4;
      }
      num3 /= (float) width;

      // Only record changes big enough
      if (Mathf.Abs (num3 - volume) > bin)
        volume = num3;

      volume = Mathf.Clamp01 (volume * 2);
      volume *= 0.3f;

      output = Mathf.Lerp (output, volume, Time.deltaTime * Mathf.Abs (maxWeight));
    }
    else
    {
      output = 0f;
    }
  }


  private void LateUpdate ()
  {
    skinnedMeshRenderer.SetBlendShapeWeight(blendShapeIndex, output * maxWeight);
  }

}