Hi, Last I checked the AudioRecord read is a blocking operation, you don't need to have to "poll" for data..just set up a second thread that constantly reads. It will read as fast as possible. The amount of "blocking" in the read is the size of the buffer chosen....
-niko On Feb 15, 7:35 am, Wanderer <[email protected]> wrote: > Hello Android Developers! > > My Android Java Application needs to record audio data into the RAM > and process it. This is why I use the class "AudioRecord" and not the > "MediaRecorder" (records only to file). > > Till now, I used a busy loop polling with "read()" for the audio data. > this has been working so far, but it peggs the CPU too much. Between > two polls, I put the thread to sleep to avoid 100% CPU usage. However, > this is not really a clean solution, since the time of the sleep is > not guaranteed and you must subtract a security time in order not to > loose audio snippets. This is not CPU optimal. I need as many free CPU > cycles as possible for a parallel running thread. > > Now I implemented the recording using the > "OnRecordPositionUpdateListener". This looks very promising and the > right way to do it according the SDK Docs. Everything seems to work > (opening the audio device, read()ing the data etc.) but the Listner is > never called. > > Does anybody know why? > > Info: I am working with a real Device, not under the Emulator. The > Recording using a Busy Loop basically works (however not satifiying). > Only the Callback Listener is never called. > > Here is a snippet from my Sourcecode: > > ______________________________________________ snip! > public class myApplication extends Activity { > > /* audio recording */ > private static final int AUDIO_SAMPLE_FREQ = 16000; > private static final int AUDIO_BUFFER_BYTESIZE = AUDIO_SAMPLE_FREQ * > 2 * 3; // = 3000ms > private static final int AUDIO_BUFFER_SAMPLEREAD_SIZE = > AUDIO_SAMPLE_FREQ / 10 * 2; // = 200ms > > private short[] mAudioBuffer = null; // audio buffer > private int mSamplesRead; // how many samples are recently read > private AudioRecord mAudioRecorder; // Audio Recorder > > ... > > private OnRecordPositionUpdateListener mRecordListener = new > OnRecordPositionUpdateListener() { > > public void onPeriodicNotification(AudioRecord recorder) { > mSamplesRead = recorder.read(mAudioBuffer, 0, > AUDIO_BUFFER_SAMPLEREAD_SIZE); > if (mSamplesRead > 0) { > > // do something here... > > } > } > > public void onMarkerReached(AudioRecord recorder) { > Error("What? Hu!? Where am I?"); > } > }; > > ... > > public void onCreate(Bundle savedInstanceState) { > > try { > mAudioRecorder = new AudioRecord( > android.media.MediaRecorder.AudioSource.MIC, > AUDIO_SAMPLE_FREQ, > AudioFormat.CHANNEL_CONFIGURATION_MONO, > AudioFormat.ENCODING_PCM_16BIT, > AUDIO_BUFFER_BYTESIZE); > } catch (Exception e) { > Error("Unable to init audio recording!"); > } > > mAudioBuffer = new short[AUDIO_BUFFER_SAMPLEREAD_SIZE]; > > mAudioRecorder.setPositionNotificationPeriod(AUDIO_BUFFER_SAMPLEREAD_SIZE); > mAudioRecorder.setRecordPositionUpdateListener(mRecordListener); > mAudioRecorder.startRecording(); > > /* test if I can read anything at all... (and yes, this here > works!) */ > mSamplesRead = mAudioRecorder.read(mAudioBuffer, 0, > AUDIO_BUFFER_SAMPLEREAD_SIZE); > > } > > } > > ______________________________________________ snip! -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
