Eric HUBERT's profile - activity

Yep. It worked for me. I did not, however, made an exhaustive bach of tests. However, the license of the GNU STL is to restrictive, so now I am using STL PORT shared for everything.

Hello, Actually I did the test myself. recompiled native_camera, opencv and all my libs with gnustl_shared and all my issues disappeared. I also tried with everything using stlport_shared, and also stlport_static. no issues neither.

My original issue was that native_camera was using stlport and I was using gnustl for every others libs. Using 2 different kinds of STL was bad. (I do recompile opencv)

I guess it is mandatory to use stlport when recompiling opencv. My bad if I missed any warning/default config or anything else.

Anyway, thanks a lot for your help!

Thank you for your precious help. I see in the build instructions the flag "-DANDROID_USE_STLPORT=ON" . and I'm guessing maybe this can be a good hint. Since my app uses multiple shared libraries (including OpenCV ones) and since It is advised to use a single SHARED version of the STL then...

(see CPLUSPLUS-SUPPORT.html from the NDK.)

I will try to build libnative_camera with the gnustl_shared.so I'm using for everything else and see if it fixes my issue.

Will keep you informed. (since it might be a good idea in opencv build scripts to use the same shared STL)

Hello everyone,

I'm having hard times finding the root cause of an issue in my native android app using OpenCV video camera feature. And since the libnative_camera source code is not public (unless I'm making a mistake) It's difficult to understand it.

    signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr deadbaad
    ...
    #00  pc 0000effc  /system/lib/libc.so
    #01  pc 00011da3  /system/lib/libc.so (dlfree+1458)
    #02  pc 0000cf13  /system/lib/libc.so (free+10)
    #03  pc 0000b28f  /data/app-lib/com.xxx-1/libnative_camera_r4.2.0.so (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()+4)
    #04  pc 00040c90  /data/app-lib/com.xxx-1/libplgExtVideo.so (-----)

The weird part is that there absolutely no link in my source code between stack #04 and #03.

Is there any way to get a debug version of the libnative_camera ? about its source code? Does it run some static initialization code? Did someone encounter a similar issue?

thanks!

My defect and proposed fix has been accepted and merged into the 2.4.7 branch http://code.opencv.org/issues/3201

Thank you for the idea, but it won't help me. the "try_index" used within the DShow wrapper makes that even if I start with index 99, it will use the "last" camera from its own list.

Hello,

In my program (MultiPlatform C++ using OpenCV 2.4.6) , I am trying to determine how many video inputs are available. There is no straightforward API for that, so I'm doing a small workaround:

I try and init a new VideoCapture with an increasing index until it fails. (isOpened() returns false)

while(bOk)
{
    test = new cv::VideoCapture(i++);
    bOk = test->isOpened();
    ...
}

While it's working on linux (with V4L2) it fails on Windows (with DirectShow) since the OpenCV Dshow wrapper, when requested to open a camera index out of bound, decides to use the last available one. (so I'm getting 99 working inputs)

cf cap_dshow.cpp l.3172

try_index = try_index < 0 ? 0 : (try_index > devices-1 ? devices-1 : try_index);

Is there any particular reason for this behaviour? (I did not find an obvious one on the source history) maybe is this a workaround for a dshow issue?

Thank you

Edit : The "fall back" behavior should be, in my opinion, a decision from the caller, and not the lib itself. I did a fix yesterday, it seems to be working perfectly. So I assume there is no issue from dshow. I added an issue in the tracker and made a pull request for the fix. I hope it will make it into the 2.4.7 : http://code.opencv.org/issues/3201