CODEWITHSUNDEEP
c#androidaudioxamarinxamarin-studio
Brandon Boone
Brandon Boone

Reputation: 37

Xamarin: Playing sound for a minute

I am trying to play one minute of sound. I can do that, but the way I was doing it would generate the sound buffer 1st then play it and that was taking too much time, there was a big delay. so now I am trying to generate the sound buffer while playing it.so there would be no delay. It plays for like 4 secs and then stops, but I can't click my button again for like a min. so I think the code is still running even though I can't hear anything.

here is my code:

public void play()
    {   
        short[] buffer = new short[44100];
        track = new AudioTrack (Stream.Music, 44100, ChannelOut.Mono, Encoding.Pcm16bit, 5292000, AudioTrackMode.Static);
        track.SetPlaybackRate (44100);
        while (n2 < 5292000) {
            for (int n = 0; n < 44100; n++) {

                float temp1 = (float)( Amplitude * Math.Sin ((2 * Math.PI * Frequency * n2) / 44100D));
                byte[] bytes = BitConverter.GetBytes (temp1);
                buffer [n] = (short)(temp1 * short.MaxValue);
                n2++;
            }
            int buffer_number = track.Write (buffer, 0, buffer.Length);
            track.Play();
        }

        track.Release();
    }

I tried to use AudioTrackMode Stream but when the program get to Track.play is throw a runtime error: play() called on uninitialized AudioTrack.

so what am I doing wrong?

Upvotes: 0

Views: 1874

Answers (1)

Jmorvan
Jmorvan

Reputation: 1040

Here is a condensed version of how I got it to work in c# based on the android sample at:

http://marblemice.blogspot.fr/2010/04/generate-and-play-tone-in-android.html

public void playSound()
        {   
            var duration = 1;
            var sampleRate = 8000;
            var numSamples = duration * sampleRate;
            var sample = new double[numSamples];
            var freqOfTone = 1900;
            byte[] generatedSnd = new byte[2 * numSamples];

            for (int i = 0; i < numSamples; ++i) {
                sample[i] = Math.Sin(2 * Math.PI * i / (sampleRate/freqOfTone));
            }

            int idx = 0;
            foreach (double dVal in sample) {
                short val = (short) (dVal * 32767);
                generatedSnd[idx++] = (byte) (val & 0x00ff);
                generatedSnd[idx++] = (byte) ((val & 0xff00) >> 8);
            }

            var track = new AudioTrack (global::Android.Media.Stream.Music, sampleRate, ChannelOut.Mono, Encoding.Pcm16bit, numSamples, AudioTrackMode.Static);
            track.Write(generatedSnd, 0, numSamples);
            track.Play ();
        }

Adjust durationand `freqOfTone``acording to your needs.

Upvotes: 1

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