Question

我有一些代码应该从AudioRecord获取振幅。问题是数学只返回-Infinity。我能不能再和我一起看一下眼睛：

private class measureSnoreAudio extends AsyncTask<String, String, String> {

    @Override
    protected String doInBackground(String... params) {


            Log.d(TAG, "Creating the buffer of size " + BUFFER_SIZE);
            byte[] buffer = new byte[BUFFER_SIZE];

            Log.d(TAG, "Creating the AudioRecord");
            recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
                    RECORDING_RATE, CHANNEL, FORMAT, BUFFER_SIZE * 10);

            Log.d(TAG, "AudioRecord recording...");
            recorder.startRecording();

            while (isRecordingSnore) {

                // read the data into the buffer
                int read = recorder.read(buffer, 0, buffer.length);
                int amplitude = (buffer[0] & 0xff) << 8 | buffer[1];

                // Determine amplitude
                double amplitudeDb = 20 * Math
                        .log10(Math.abs(amplitude) / 32768);
                String dbString = String.valueOf(amplitudeDb);
                Log.d("Snore DB", "dB " + dbString);
                //TextView textAmplitude = (TextView) findViewById(R.id.tvAmplitude);
                //textAmplitude.setText(dbString);
            }

            Log.d(TAG, "AudioRecord finished recording");
        return null;
    }
}

Answer 1

double amplitudeDb = 20 * Math.log10(Math.abs(amplitude) / 32768);

我想问题可能来自Math.abs（幅度）/ 32768，幅度是整数，所以Math.abs（幅度）也将返回整数，因为Math.abs（幅度）小于32768（也许我是不正确，字节最大2 ^ 7 - 1，这里幅度可以大于32768吗？）。所以Math.abs（幅度）/ 32768等于0.Log10（0）是-Infinity，我在Eclipse中用Java项目测试过。您可以更改为

double amplitudeDb = 20 * Math.log10((double)Math.abs(amplitude) / 32768);

来自AudioRecord的幅度

1 个答案: