Hello
I have a music (sequencer/synth) app in Android Market. One of its
strengths is that it uses very little resources and plays smoothly
even on the oldest and cheapest devices and only requires Android
version 1.6.
However, since the arrival of ICS, I get more and more complaints
about stuttering playback and a sluggish interface, mainly on Galaxy
Nexus. The app hasn't changed and still works fine on earlier versions
of Android.
I wonder what may have changed.
My app does the audio processing in native code and I suspect the way
data are passed between java and native might be the problem (I still
use AudioTrack to maintain 1.6 compatibility and because it always
worked fine):
public class PlayThread extends Thread
{
public void run()
{
ByteBuffer byteBuffer = ByteBuffer.allocateDirect(minSize);
byte[] byteArray = new byte[minSize];
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
int minSize =AudioTrack.getMinBufferSize( 44100,
AudioFormat.CHANNEL_CONFIGURATION_STEREO,
AudioFormat.ENCODING_PCM_16BIT );
myTrack = new AudioTrack( AudioManager.STREAM_MUSIC,
44100, AudioFormat.CHANNEL_CONFIGURATION_STEREO,
AudioFormat.ENCODING_PCM_16BIT,
minSize, AudioTrack.MODE_STREAM);
myTrack.play();
while(1)
{
byteBuffer.position(0);
processNativeAudio(byteBuffer, minSize);
byteBuffer.position(0);
byteBuffer.get(byteArray, 0, minSize);
myTrack.write( puff, 0, minSize );
}
}
}
In the main activity, a new PlayThread is created on startup. The
native function looks like this:
void Java_com_myapp_ processNativeAudio( JNIEnv * env, jobject this,
jobject buffer , jint buflng)
{
jbyte *jbuffer = (*env)->GetDirectBufferAddress(env, buffer);
short *shortBuffer= (short*)(jbuffer);
// processing audio here and writing to shortBuffer
}
Anyone has similar problems or even knows a workaround?
Thank you.
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