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Re: [Java-player-users] More JavaClient camera woes
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From: Raymond S. <rsh...@ra...> - 2006-02-08 00:46:51
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Hi Radu,
Thanks for that! It seems to be working a lot more sensibly now ... I can
get images coming through nicely but the problem is every now and again I
get warnings from the server side:
===================
<...>
warning : 21117 bytes leftover on write() to client
warning : 50498 bytes leftover on write() to client
warning : 10374 bytes leftover on write() to client
warning : 3077 bytes leftover on write() to client
<...>
===================
When I get these, the images have varying degrees of corruption and often
they're also associated with the client giving the error:
===================
<...>
[PlayerClient] : Unknown message type received in read()
<...>
===================
This tends to happen less if I use the CameraCompress driver rather than
the v4l driver (and modify the file handling code at the client end
appropriately) presumably because the data size is smaller but it seems to
still happen every now and again (especially if the data size is above
about 55k or so).
Any ideas as to where to look?
Cheers!
- Raymond
At 05:28 PM 7/02/2006 +0100, you wrote:
>Hey Reymond,
>(good to have you onboard!)
>
>I just checked the Camera interface, and you are right, it wasn't
>processing the images correctly. The fix was trivial though (I might have
>missed it since my tests were done with cameras with very low resolution).
>
>Basically you need to modify CameraInterface.java and replace the
>following two lines (in readData()):
>- for (int i = 0; i < PLAYER_CAMERA_IMAGE_SIZE; i++)
>- image[i] = (byte)is.readUnsignedByte (); /* compressed
>image data */
>with:
>+ int totalBytes = 13;
>+ int bytes;
>+ while (totalBytes < this.size)
>+ {
>+ // read the compressed image data
>+ bytes = is.read (image, totalBytes - 13, this.size
>- totalBytes);
>+ totalBytes += bytes;
>+ }
>
>I have also attached a patch (use patch -p1 < javaclient.camera.patch) to
>this e-mail, and have also commited these changes to the CVS SF
>repository. Please, if possible, use the Javaclient HEAD (from CVS) - see
>instructions at http://sourceforge.net/cvs/?group_id=135304 - and Player 1.6.5.
>
>Ah, I also added an example on how to use the Camera to our examples web
>page (http://java-player.sourceforge.net/examples.php).
>
>P.S. No need to use cam.readData() if you run the client in threaded mode
>(runThreaded...).
>
>PPS. I just discovered a bug in the non-threaded version of the client, so
>please, if possible, use in threaded mode at all times until I get a
>chance to fix it.
>
>Cheers,
>Radu.
>
>--
>| Radu Bogdan Rusu | http://rbrusu.com/
>| http://www9.cs.tum.edu/people/rusu/
>| Intelligent Autonomous Systems
>| Technische Universitaet Muenchen
>
>
>Raymond Sheh wrote:
>
>>Hi all!
>>
>>I'm trying to get CameraInterface working, much like Sunny was (list
>>email 2005-09-15, can't figure out how to reply to the same thread since
>>I just joined). I'm getting really weird things coming in and it looks
>>like things are getting somewhat mixed up. This is before I even try to
>>decode the image - the headers look a little messed up.
>>
>>Here's my code, basically a gutted version of SpaceWandererExample:
>>
>>===============
>>public class Blah
>>{
>> public static void main (String[] args)
>> {
>> PlayerClient interlink = new
>> PlayerClient("192.168.1.10", 6665);
>> CameraInterface cam =
>> interlink.requestInterfaceCamera(1, 'r');
>> interlink.runThreaded (-1, -1);
>> try { Thread.sleep (1000); } catch (Exception e) { }
>> while (true)
>> {
>> cam.readData();
>> System.out.println("Got data\n");
>> System.out.println("Camera size is " +
>> cam.getWidth() + "/" + cam.getHeight());
>> }
>> }
>>}
>>===============
>>
>>Here's the output I get:
>>===============
>>$ java Blah
>>Player v.1.6.4
>>[PlayerClient] : Got response for device 40(cameracompress) with access: r
>>[PlayerClient] : Unknown message type received in read()
>>[PlayerClient] : Unknown message type received in read()
>>[PlayerClient] : Unknown message type received in read()
>>[PlayerClient] : Unknown message type received in read()
>>[PlayerClient] : Unknown message type received in read()
>>[PlayerClient] : Unknown message type received in read()
>>[PlayerClient] : Unknown message type received in read()
>>[PlayerClient] : Unknown message type received in read()
>>Got data
>>
>>Camera size is 5121/6898
>>[PlayerClient] : Unknown message type received in read()
>>[PlayerClient] : Unknown message type received in read()
>>Got data
>>
>>Camera size is -2647/-9978
>>[PlayerClient] : Unknown message type received in read()
>><...>
>>===============
>>Funnily enough, the program seems to block for a long time at the line
>>"cam.readData();" (generally the "Got data" line appears after a long pause).
>>
>>I'm sure the Player server side of things works - we have another Player
>>client that connects via the standard C++ interface libraries and it
>>seems to behave nicely. The camera itself is the standard V4L driver
>>hooked through CameraCompress (but the same thing happens when I direct
>>Player to any of the other cameras on our robots).
>>
>>
>>Anyone have any ideas as to what might be happening? I notice the
>>documentation says something about this interface not being intended for
>>server-client, what does that actually mean in terms of useability? Radu,
>>what did you have to do when you dived into the player driver as you
>>mentioned in your reply to Sunny's email?
>>
>>
>>Cheers!
>>
>>- Raymond
>
>
>
>diff -r -u javaclient-cvs/CameraInterface.java javaclient/CameraInterface.java
>--- javaclient-cvs/CameraInterface.java 2005-06-01 21:05:47.000000000 +0200
>+++ javaclient/CameraInterface.java 2006-02-07 16:50:56.000000000 +0100
>@@ -17,7 +17,7 @@
> * along with this program; if not, write to the Free Software
> * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> MA 02111-1307 USA
> *
>- * $Id: CameraInterface.java,v 1.3 2005/06/01 19:05:47 veedee Exp $
>+ * $Id: CameraInterface.java,v 1.6 2006/02/07 15:50:56 veedee Exp $
> *
> */
> package javaclient;
>@@ -31,6 +31,7 @@
> * @author Radu Bogdan Rusu
> * @version
> * <ul>
>+ * <li>v1.6.5 - bug fixes (image data was corrupted previously)
> * <li>v1.6.3 - Player 1.6.3 (all interfaces) supported
> * <li>v1.6.2 - Player 1.6.2 supported, Javadoc documentation,
> several bugfixes
> * </ul>
>@@ -99,8 +100,15 @@
> fdiv = (short)is.readUnsignedShort (); /* scale
> divisor */
> compression = (byte)is.readUnsignedByte (); /* image
> compression status */
> image_size = is.readInt (); /* size of
> image data */
>- for (int i = 0; i < PLAYER_CAMERA_IMAGE_SIZE; i++)
>- image[i] = (byte)is.readUnsignedByte (); /* compressed
>image data */
>+
>+ int totalBytes = 13;
>+ int bytes;
>+ while (totalBytes < this.size)
>+ {
>+ // read the compressed image data
>+ bytes = is.read (image, totalBytes - 13, this.size
>- totalBytes);
>+ totalBytes += bytes;
>+ }
> } catch (Exception e) {
> System.err.println ("[Camera] : Error when reading payload:
> " + e.toString ());
> }
>
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