Real-time audio recording and sending

Question

I try to capture the sound from the microphone and no matter what size ( bufferSizeInBytes) buffer I set during construction AudioRecord, when I do a AudioRecord.readI always get 8192bytes of audio data (128 Miz). I would like to AudioRecord.readbe able to read 40msdata ( 2560 bytes). The only working code example I can find is Sipdroid ( RtpStreamSender.java), which I have not tried. Here is the relevant snippet of my code:

public void run()
{ 
running = true; 
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URG ENT_AUDIO); 
try { 
     frameSize = AudioRecord.getMinBufferSize(samplingRate, 
              AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT); 
     Log.i(TAG, "trying to capture " + String.format("%d", frameSize) + " bytes"); 
     record = new AudioRecord(MediaRecorder.AudioSource.MIC, samplingRate, 
    AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, frameSize);
     record.startRecording(); 
     byte[] buffer = new byte[frameSize]; 
     while (running)
     { 
        record.read(buffer, 0, frameSize); 
        Log.i(TAG, "Captured " + String.format("%d", frameSize) + " bytes of audio"); 
     } 
     record.stop(); 
     record.release(); 
 } catch (Throwable t) { 
 Log.e(TAG, "Failed to capture audio"); 
   } 
 }

My questions / comments:

• Is this a limitation of the AudioRecord class and / or specific device?
• I do not see a method for requesting a supported sample rate (bufferSizeInBytes steps) that this device can execute. It would be nice if there was one.
• AudioRecord.OnRecordPositionUpdateListener ?
• pcm 8 . ? - sipdroid, . ,