Android使用AudioRecord判斷是否有音頻輸入

更新時間：2017年01月13日 09:40:40 作者：andywuchuanlong

這篇文章主要介紹了Android使用AudioRecord判斷是否有音頻輸入的實例代碼，非常不錯，具有參考借鑒價值，需要的的朋友參考下吧

Android黨都應該玩過一個叫吹裙子的游戲，這個游戲就是原理就是通過監(jiān)聽用戶吹出的氣的力度來決定如何把MM的裙子弄飛起來的，所以關鍵在于如何判斷用戶吹氣的力度問題。現在公司剛好有這個需求要評估就是需要一直監(jiān)聽用戶的語音輸入，當在兩秒內沒有語音輸入時候就暫停某項事情，有語音輸入的時候就要繼續(xù)做某件事。其實這兩件事情的本質原理是一樣的，就是通過這AudioRecord來處理用戶輸入的原始音頻數據，從而計算出當前用戶輸入的音量大小來判斷用戶是否有語音輸入。下面貼上一段代碼用戶可以自行研究。

public static int calculateVolume(byte[] var0, int var1) {
    int[] var3 = null;
    int var4 = var0.length;
    int var2;
    if(var1 == 8) {
      var3 = new int[var4];
      for(var2 = 0; var2 < var4; ++var2) {
        var3[var2] = var0[var2];
      }
    } else if(var1 == 16) {
      var3 = new int[var4 / 2];
      for(var2 = 0; var2 < var4 / 2; ++var2) {
        byte var5 = var0[var2 * 2];
        byte var6 = var0[var2 * 2 + 1];
        int var13;
        if(var5 < 0) {
          var13 = var5 + 256;
        } else {
          var13 = var5;
        }
        short var7 = (short)(var13 + 0);
        if(var6 < 0) {
          var13 = var6 + 256;
        } else {
          var13 = var6;
        }
        var3[var2] = (short)(var7 + (var13 << 8));
      }
    }
    int[] var8 = var3;
    if(var3 != null && var3.length != 0) {
      float var10 = 0.0F;
      for(int var11 = 0; var11 < var8.length; ++var11) {
        var10 += (float)(var8[var11] * var8[var11]);
      }
      var10 /= (float)var8.length;
      float var12 = 0.0F;
      for(var4 = 0; var4 < var8.length; ++var4) {
        var12 += (float)var8[var4];
      }
      var12 /= (float)var8.length;
      var4 = (int)(Math.pow(2.0D, (double)(var1 - 1)) - 1.0D);
      double var14 = Math.sqrt((double)(var10 - var12 * var12));
      int var9;
      if((var9 = (int)(10.0D * Math.log10(var14 * 10.0D * Math.sqrt(2.0D) / (double)var4 + 1.0D))) < 0) {
        var9 = 0;
      }
      if(var9 > 10) {
        var9 = 10;
      }
      return var9;
    } else {
      return 0;
    }
}

上述方法的形參中的一個字節(jié)數組便是當前捕捉到用戶輸入的原始音頻數據，第二個形參則是音頻數據格式位PCM，16位每個樣本，比如如果音頻數據格式設為AudioFormat.ENCODING_PCM_16BIT，則參數傳16。最后實現的效果就是如下：

01-12 18:54:17.222 E/recordtest(24249): no voice input
…………….
01-12 18:54:19.027 E/recordtest(24249): no voice input
01-12 18:54:19.067 E/recordtest(24249): no voice input
01-12 18:54:19.105 E/recordtest(24249): no voice input
01-12 18:54:19.145 E/recordtest(24249): no voice input
01-12 18:54:19.188 E/recordtest(24249): no voice input
01-12 18:54:19.227 E/recordtest(24249): no voice input
01-12 18:54:19.228 E/recordtest(24249): no voice input in 2 sec
01-12 18:54:19.269 E/recordtest(24249): no voice input
01-12 18:54:19.306 E/recordtest(24249): no voice input
01-12 18:54:19.345 E/recordtest(24249): no voice input
01-12 18:54:19.387 E/recordtest(24249): no voice input
01-12 18:54:19.427 E/recordtest(24249): no voice input
01-12 18:54:19.466 E/recordtest(24249): has voice input
01-12 18:54:19.505 E/recordtest(24249): has voice input
01-12 18:54:19.546 E/recordtest(24249): has voice input
01-12 18:54:19.586 E/recordtest(24249): has voice input
01-12 18:54:19.646 E/recordtest(24249): has voice input
01-12 18:54:19.686 E/recordtest(24249): has voice input
01-12 18:54:19.726 E/recordtest(24249): has voice input
01-12 18:54:19.766 E/recordtest(24249): has voice input