How to improve quality of sound when I generate it using AudioTrack?

Question

I wish to improve quality of beeps, which generated by class AudioTrack. I tried to use stereo format, but it don't help. How can I improve quality of sounds, which generated by AudioTrack?

Below you can see code, which shows, how I generated sound in high quality, but beep unfortunately plays in in a very bad quality.

class beeper {

    private static byte generatedSnd[];
    public static AudioTrack audioTrack;

    public static void createAudioTrack() {
        if (audioTrack == null) {
            audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
                    48000,
                    AudioFormat.CHANNEL_OUT_STEREO,
                    AudioFormat.ENCODING_PCM_16BIT,
                    generatedSnd.length,
                    AudioTrack.MODE_STREAM);

            if (Build.VERSION.SDK_INT < 21)
                audioTrack.setStereoVolume(AudioTrack.getMaxVolume(),
                        AudioTrack.getMaxVolume());
            else
                audioTrack.setVolume(AudioTrack.getMaxVolume());

            audioTrack.setPlaybackPositionUpdateListener(
                    new OnPlaybackPositionUpdateListener() {
                @Override
                public void onMarkerReached(AudioTrack track) {
                }
                @Override
                public void onPeriodicNotification(AudioTrack track) {
                }
            });
        }
    }

    static void sound(double frequency, double durationMs) {
        generatedSnd = new byte[(int) (2 * 48000 * durationMs / 1000)];
        double sample[] = new double[(int) (48000 * durationMs / 1000)];
        for (int i = 0; i < sample.length; ++i) {
            sample[i] = Math.sin(2 * Math.PI * i / (48000 / frequency));
        }
        int idx = 0;
        for (final double dVal : sample) {
            final short val = (short) ((dVal * 32767));
            generatedSnd[idx++] = (byte) (val & 0x00ff);
            generatedSnd[idx++] = (byte) (val & 0xff00 >>> 8);
        }
        createAudioTrack();
        audioTrack.play();
        audioTrack.write(generatedSnd, 0, generatedSnd.length);
    }

    public static void audioTrackdestroy() {
        if (audioTrack != null) {
            audioTrack.stop();
            audioTrack.flush();
            audioTrack.release();
            audioTrack = null;
        }
    }
}

It looks like you're having some problems with your code indentation - would you fix that first please, and repair it in your question too? Thanks. — halfer, Nov 20 '16 at 23:50

nandsito · Answer 1 · 2016-11-22T16:13:02.520

0

The shift operator has a higher precedence than the bitwise AND (reference) so you probably mean:

generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8)

UPDATE

Your audio track should be MONO instead of STEREO to match your wave generator function, or else the frequency will be doubled.

Try calling audioTrack.stop() right after audioTrack.write().

edited Nov 22 '16 at 16:13

answered Nov 21 '16 at 05:15

nandsito

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yes,you right about shift operator,but i can't understand how improve quality of sound usin audiotrack – alexandr kozlovskiy Nov 21 '16 at 11:00
@alexandrkozlovskiy does the sound remains bad after the shift operator fix? – nandsito Nov 21 '16 at 11:30
The quality of sound is not change,because it was my error,when i copy code in this topic. Also,when i generate a lotof sounds,in differents frequncys,the sound change frequency slow,as i wish,but it choppy. Help me please solve problems with quality of sound,which i generate using audiotrack – alexandr kozlovskiy Nov 22 '16 at 15:29

How to improve quality of sound when I generate it using AudioTrack?

1 Answers1

UPDATE