Hi,
Using the CameraPreview example and doing some image processing I
found a strange slow behavior in the Emulator. I have little
experience with java and Android (C/C++ background) so I do not know
if it is a true issue of the emulator or some strange memory/thread
handling that I am not aware.
When the application starts after the emulator starts, the application
is very slow (228 ms per frame).
If I press the "Back" button and then press the application icon, The
applications is about 4 times faster (64ms per frame).
This fast framerate will continue to work and will not go back to the
slow behavior.
I tried launching the emulator from Eclipse and stand alone. Also in
Windows and OSX and the behavior is always the same and happens every
time.
To recreate the slow behavior I just added a couple of lines (intense
CPU usage) to the CameraPreview sample provided by the SDK.The
modified run() part is:
@Override
public void run() {
// We first open the CameraDevice and configure it.
CameraDevice camera = CameraDevice.open();
if (camera != null) {
CameraDevice.CaptureParams param = new
CameraDevice.CaptureParams();
param.type = 1; // preview
param.srcWidth = 1280;
param.srcHeight = 960;
param.leftPixel = 0;
param.topPixel = 0;
param.outputWidth = 320;
param.outputHeight = 240;
param.dataFormat = 2; // RGB_565
camera.setCaptureParams(param);
}
// This is our main acquisition thread's loop, we go until
// asked to quit.
SurfaceHolder holder = mHolder;
//
===========================================================
// Added to check strange behavior
//
===========================================================
long timeMillis = java.lang.System.currentTimeMillis();
Paint paint = new Paint();
paint.setTextSize(20);
paint.setARGB(255, 255, 0, 0);
while (!mDone) {
// Lock the surface, this returns a Canvas that can
// be used to render into.
Canvas canvas = holder.lockCanvas();
// Capture directly into the Surface
if (camera != null) {
camera.capture(canvas);
//
===========================================================
// Added to check strange behavior
//
===========================================================
int b=3;
for(int i=0; i<100000; i++)
b=b+1;
long timeNew =
java.lang.System.currentTimeMillis();
canvas.drawText("ms=" + (timeNew - timeMillis),
10, 20,
paint);
timeMillis = timeNew;
}
// And finally unlock and post the surface.
holder.unlockCanvasAndPost(canvas);
}
// Make sure to release the CameraDevice
if (camera != null)
camera.close();
}
Can someone test it and see if the results are the same? Any ideas?
Thanks
Franco
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