Android 混合音频，评价算法

使用平均算法混合两路音频，两路音频必须采样率及单双声道都要相同。

//bMulRoadAudioes为数据源二位数组。
public byte[] mixRawAudioBytes(byte[][] bMulRoadAudioes) {

            if (bMulRoadAudioes == null || bMulRoadAudioes.length == 0)
                return null;

            byte[] realMixAudio = bMulRoadAudioes[0];

            if(bMulRoadAudioes.length == 1)
                return realMixAudio;

            for(int rw = 0 ; rw < bMulRoadAudioes.length ; ++rw){
                if(bMulRoadAudioes[rw].length != realMixAudio.length){
                    Log.e("app", "column of the road of audio + " + rw +" is diffrent.");
                    return null;
                }
            }

            int row = bMulRoadAudioes.length;
            int coloum = realMixAudio.length / 2;
            short[][] sMulRoadAudioes = new short[row][coloum];

            for (int r = 0; r < row; ++r) {
                for (int c = 0; c < coloum; ++c) {
                    sMulRoadAudioes[r][c] = (short) ((bMulRoadAudioes[r][c * 2] & 0xff) | (bMulRoadAudioes[r][c * 2 + 1] & 0xff) << 8);
                }
            }

            short[] sMixAudio = new short[coloum];
            int mixVal;
            int sr = 0;
            for (int sc = 0; sc < coloum; ++sc) {
                mixVal = 0;
                sr = 0;
                for (; sr < row; ++sr) {
                    mixVal += sMulRoadAudioes[sr][sc];
                }
                sMixAudio[sc] = (short) (mixVal / row);
            }

            for (sr = 0; sr < coloum; ++sr) {
                realMixAudio[sr * 2] = (byte) (sMixAudio[sr] & 0x00FF);
                realMixAudio[sr * 2 + 1] = (byte) ((sMixAudio[sr] & 0xFF00) >> 8);
            }

            return realMixAudio;
        }