Epson BT-2000 Developers Guide - Page 80

 Usage procedure // App developer applies processing when acquiring image data private Camera.PreviewCallback mPreviewCB = new Camera.PreviewCallback() { @Override public void onPreviewFrame(byte data[], Camera camera) { Log.d(TAG, "Save preview image"); synchronized (lockObject) { savePreviewData(data); } // Register the buffer to be used camera.addCallbackBuffer(mPreviewData); } }; // Register the buffer to be used camera.addCallbackBuffer(mPreviewData); //Register the callback method at the optimal time camera.setPreviewCallbackWithBuffer(mPreviewCB);  Important points  You need to reserve the buffer region from the application.  This provides high-speed processing when compared to setPreviewCallback or setOneShotPreviewCallback by securing and opening the memory.  The application developer needs to describe the buffer management process. Specifically, the following processes are necessary.  Register the buffer to be used in addCallbackBuffer described later.  Calculate the size of the buffer to be registered as the width x height x 1 pixel byte. The width and the height should both be higher than their respective resolutions.  Each time onPreviewFrame is called, you need to re-register the buffer.  If no buffer is registered, the frame is corrupted and is not called by the callback method.  You can register multiple buffers. MOVERIO Pro Developer's Guide (Rev.1.0) 76