Closed GoogleCodeExporter closed 8 years ago
Then OpenCV 2.2 cannot capture from your Webcam.. What else do you expect to
hear from me?
Original comment by samuel.a...@gmail.com
on 20 Mar 2011 at 7:20
I am able to do this in c++ w/ OpenCV, so I'm just trying to find the missing
link here w/ javacv.
Original comment by jack.nan...@gmail.com
on 20 Mar 2011 at 7:26
Well, it works just fine here.. If you figure out what is missing, let me know
Original comment by samuel.a...@gmail.com
on 20 Mar 2011 at 7:30
I got the same problem trying to run the example code. Here is the exception:
(<unknown>:8737): GStreamer-CRITICAL **: gst_debug_add_log_function: assertion
`func != NULL' failed
java.lang.Exception: cvCreateCameraCapture() Error: Could not create camera
capture.
at com.googlecode.javacv.OpenCVFrameGrabber.start(OpenCVFrameGrabber.java:98)
at graphics.CVprocessing.<init>(CVprocessing.java:15)
at main.setupInterface(main.java:40)
at main.main(main.java:29)
I use ubuntu 11.04 with eclipse. After placing the jars int the project and
compiling the OpenCV libraries (from OpenCV svn) with all the options enabled I
got the message. Anyway, it's an "assertion" so I doubt it is related with libs
(because the JNA exceptions would have raised before)
Original comment by alvaroaccionmontes@gmail.com
on 29 Apr 2011 at 1:13
JavaCV now uses JavaCPP instead of JNA. You should try to upgrade to the latest
version to see if it fixes your issue. (Also, make sure OpenCV 2.2 works from a
program in C/C++. It's probably not JavaCV's fault...)
Original comment by samuel.a...@gmail.com
on 29 Apr 2011 at 3:09
It works from both C++ and python.
I've tried to do what you suggested, but when I try to build the project it
gives an error saying there is a header missing. (OpenCV_core.h I think it
was). Well, if I arrive the solution I'll tell. Thanks.
Original comment by alvaroaccionmontes@gmail.com
on 29 Apr 2011 at 9:14
In any case, seems to be a bug in gstreamer:
https://bugzilla.gnome.org/show_bug.cgi?id=640771
Try to upgrade to the latest prerelease and see if that fixes it. If it does
not, let me know, thanks.
Original comment by samuel.a...@gmail.com
on 30 Apr 2011 at 1:39
I've switched to a proposed upgrade (latest package in Ubuntu 11.04) and the
problem persists. Not sure if that upgraded the buggy lib since it was
mentioned only the phonon back-end. I can try to debug the process if you want
me to do it.
Original comment by alvaroaccionmontes@gmail.com
on 30 Apr 2011 at 1:35
If you cannot provide more details than that, then just wait for the next
release of gstreamer and let me know if that one fails too, thanks
Original comment by samuel.a...@gmail.com
on 30 Apr 2011 at 2:21
Sorry for being so lazy, but I'm not a professional developer, only a mere
first year student. After some debugging I can tell you that the program
crashes immediately after a call to the method
ClassLoader.findNative(ClassLoader,String): Line 1771
The next method called is opencv_highgui.cvCreateCameraCapture(int), that is
the native method of the Opencv libs. So now the
If you know how to debug the Java virtual machine itself I can give it a shoot.
I will try with the function of Gstreamer that OpenCV uses after locating it in
the source to see if the problem is the same.
And believe me, I'm not trying to make you lose your time.
Original comment by alvaroaccionmontes@gmail.com
on 30 Apr 2011 at 2:45
I've tweaked the source of OpenCV to avoid calling any function of gstreamer
from the native call you imlemented, and the exception that raises is this one:
java.lang.Exception: cvCreateCameraCapture() Error: Could not create camera
capture.
So I think we can conclude that the problem is from gstreamer itself.
Thanks for your time.
Original comment by alvaroaccionmontes@gmail.com
on 30 Apr 2011 at 3:15
More info. V4L headers have been removed from kernel, so only V4Lv2 remains.
This causes OpenCV to skip that interface and jump directly to gstreamer. You
probably have both modules so there is no problem because V4L option engages
(or because your gstreamer lib has not got this bug).
Original comment by alvaroaccionmontes@gmail.com
on 30 Apr 2011 at 3:35
Sorry, didn't mean to upset you, but some people /are/ lazy, so..
Anyway, gstreamer's fine. You say it works fine in C++ and Python, so it should
work in Java. When you use OpenCV in C++ or Python, you do not use it within
graphics.CVprocessing right? So what about using the same exact functions, in
the same exact order? Does the exact same code in C++ or Python translated to
Java still fail? And if so, what is this code? And please, no more than 10
lines, thank you
Original comment by samuel.a...@gmail.com
on 30 Apr 2011 at 3:45
Let me explain better. I have a missing header for V4L, so I cannot use that
module and the compiler skips to GStreamer.
The libs I use with C++/ python are Ubuntu packages already compiled and
tested, so the code works. And I cannot test Javacv with those because they're
v2.1.
If you can provide me with an older version of Javacv already built (I couldn't
manage to do it due to a similar issue) I'll try if the problem persists, but I
bet it would work fine in case I try. Anyway, I'll disassemble my current libs
in order to see if I my point was right.
Thanks for your hard work. Really.
Original comment by alvaroaccionmontes@gmail.com
on 30 Apr 2011 at 4:27
Here is the file with the asm code and the calls. As I supposed, it only uses
V4L.
So it is not Javacv problem. See you arround :)
Original comment by alvaroaccionmontes@gmail.com
on 30 Apr 2011 at 7:00
Attachments:
JavaCV works with OpenCV 2.2 not 2.1. Please read the README.txt file before
posting things like that next time, thank you
Original comment by samuel.a...@gmail.com
on 1 May 2011 at 2:54
Fixed in latest release:
* New `videoInputLib` wrapper and corresponding `VideoInputFrameGrabber` to capture using DirectShow, useful under Windows 7 where OpenCV and FFmpeg can fail to capture using Video for Windows
Use VideoInputFrameGrabber instead of OpenCVFrameGrabber.
Original comment by samuel.a...@gmail.com
on 11 May 2011 at 3:30
Original issue reported on code.google.com by
jack.nan...@gmail.com
on 20 Mar 2011 at 7:18