Android audiorecord instance fails

Question

I am creating an app that detects frequencies of sound playing through the mic. The analysis is done in an AsyncTask. It works when I try one note.

However, when I try to analyse 6 notes, say from different guitar strings, one after the other (with a delay of a second or so in between) it only captures maybe one more.

This is some of the LogCat output I get:

11-22 19:50:04.333: ERROR/AudioHardwareMSM72XX(1296): [doRouting]sndDevice=0,mCurSndDevice=-1
11-22 19:50:04.333: ERROR/AudioHardwareMSM72XX(1296): [SKW]do_route_audio_rpc(0, 1, 0)
11-22 19:50:04.333: ERROR/AudioHardwareMSM72XX(1296): msm72xx_enable_audpp: 0x0000
11-22 19:50:04.333: ERROR/AudioHardwareMSM72XX(1296): [doRouting]sndDevice=0,mCurSndDevice=0
11-22 19:50:30.523: ERROR/AudioHardwareMSM72XX(1296): Cannot open /dev/msm_pcm_in errno: 16
11-22 19:50:30.533: ERROR/AudioRecord(23241): Could not get audio input for record source 1
11-22 19:50:30.533: ERROR/AudioRecord-JNI(23241): Error creating AudioRecord instance: initialization check failed.
11-22 19:50:30.533: ERROR/AudioRecord-Java(23241): [ android.media.AudioRecord ] Error code -20 when initializing native AudioRecord object.

I deleted any repetitions for you all.

Here is the jist of my class:

static AudioRecord recorder;
static short[] audioData;
static int bufferSize;
static int samplerate = 8000;         
static boolean recorded = false;

@Override
protected Integer doInBackground(params) {

bufferSize= AudioRecord.getMinBufferSize(samplerate,AudioFormat.CHANNEL_CONFIGURATION_MONO,
            AudioFormat.ENCODING_PCM_16BIT)*2; 

recorder = new AudioRecord (AudioSource.MIC,samplerate,AudioFormat.CHANNEL_CONFIGURATION_MONO,
            AudioFormat.ENCODING_PCM_16BIT,bufferSize); 

    audioData = new short [bufferSize]; //short array that pcm data is put into.

    int recordingLoops = 0;
    while (recordingLoops < 4 || recorded) {  //loop until recording is running

    if (recorder.getState()==android.media.AudioRecord.STATE_INITIALIZED)
        if(recorder.getRecordingState()==android.media.AudioRecord.RECORDSTATE_STOPPED)
              recorder.startRecording();                     
        else {         
           recorder.read(audioData,0,bufferSize); 

           getFrequencyFromAudiodata(audioData);

           recorded = true;
             }        
    recordingLoops++;  
}

    if (recorder.getState()==android.media.AudioRecord.RECORDSTATE_RECORDING) 
    {
        killRecorder();
    }

    return 1;
}

Have you guys got any idea what is happening? I have done some looking around but I seem to just be running into people saying Android is 'full of bugs'.

Any help would be massively appreciated.

Thanks, Ben

Answer 1

The answer lay in this:

while (recordingLoops < 4 || recorded) 

I changed it to:

while (!recorded) 

And only set recorder to true when the array of audio data was sufficiently populated. This meant it would loop until perfect. thanks for your help Dave!

Answer 2

You might look at this answer, it looks like some thought went into handling the threading associated with AudioRecord:

Android AudioRecord class - process live mic audio quickly, set up callback function