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OpenCV 3.2.0 : Unable to open and read a video

asked 2017-07-31 08:48:36 -0600

Hi

Trying to open and read the Megamind.avi video using OpenCV 3.2 causes a segmentation fault. Is this a known problem or is the simple C++ program below in error (if so I would appreciate any pointers on what the issue may be) :

Steps to reproduce :

  • Platform : Mac OS X 10.12.4
  • Compiler : Clang++ (LLVM version 8.1.0 [clang-802.0.42])
  • OpenCV : 3.2.0 installed from macports using command line "port install opencv +contrib +eigen +opencl +python27 +qt5"
  • FFmpeg : 3.3.3 installed from macports (any variant)
  • Video : Megamind.avi from http://docs.opencv.org/3.2.0/d5/dc4/t... This video is playable using "ffplay" provided by the installed FFmpeg
  • Installed OpenCV 3.2.0 has been compiled with FFmpeg enabled (The opencv2/cvconfig.h file has "#define HAVE_FFMPEG" uncommented).
  • Simple test C++ program (given below)

    #include <iostream>
    #include <opencv2/core.hpp>
    #include <opencv2/videoio.hpp>
    int main(void)
    {
        try 
        {
            cv::VideoCapture video("Megamind.avi", cv::CAP_FFMPEG);
            if(!video.isOpened()) throw std::runtime_error("Could not open video");
         }
        catch (cv::Exception &e)
        {
            std::cout << e.what() << std::endl;
        }
        return 0;
     }
    
  • Stack trace of segmentation fault (given below)

     (lldb) target create "./scratch"
     Current executable set to './scratch' (x86_64).
     (lldb) r 
     Process 21181 launched: './scratch' (x86_64)
     Process 21181 stopped
     * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
             frame #0: 0x000000010474f962 libavutil.55.dylib`av_buffer_unref + 18
     libavutil.55.dylib`av_buffer_unref:
    ->  0x10474f962 <+18>: movq   (%rax), %rbx
         0x10474f965 <+21>: movq   %rbx, 0x8(%rsp)
         0x10474f96a <+26>: callq  0x1047630e0               ; av_freep
         0x10474f96f <+31>: movl   $0xffffffff, %eax         ; imm = 0xFFFFFFFF 
    (lldb) bt
    * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
        * frame #0: 0x000000010474f962 libavutil.55.dylib`av_buffer_unref + 18
          frame #1: 0x000000010475ac8a libavutil.55.dylib`av_frame_unref + 346
          frame #2: 0x00000001018878bd libopencv_videoio.3.2.dylib`CvCapture_FFMPEG::close() + 127
          frame #3: 0x0000000101887aac libopencv_videoio.3.2.dylib`CvCapture_FFMPEG::open(char const*) + 42
          frame #4: 0x0000000101889a33 libopencv_videoio.3.2.dylib`cvCreateFileCapture_FFMPEG + 259
          frame #5: 0x000000010188a82b libopencv_videoio.3.2.dylib`CvCapture_FFMPEG_proxy::open(char const*) + 45
          frame #6: 0x000000010188a4f1 libopencv_videoio.3.2.dylib`cvCreateFileCapture_FFMPEG_proxy(char const*) + 52
          frame #7: 0x000000010187dd34 libopencv_videoio.3.2.dylib`cvCreateFileCaptureWithPreference + 169
          frame #8: 0x000000010187ebd6 libopencv_videoio.3.2.dylib`cv::VideoCapture::open(cv::String const&, int) + 292
          frame #9: 0x000000010187e765 libopencv_videoio.3.2.dylib`cv::VideoCapture::VideoCapture(cv::String const&, int) + 51
          frame #10: 0x0000000100001dc9 scratch`main at scratch.cpp:9
          frame #11: 0x00007fffa2ead235 libdyld.dylib`start + 1
    
  • I have searched this forum and Google but have not been able to find a resolution to the problem. In view of the above it does not seem to be a Codec issue. I have checked that it is not related to paths (absolute/relative) etc. Using "cv::CAP_ANY" instead of cv::CAP_FFMPEG", or even not setting this property, does not fix the problem either.

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answered 2017-08-23 08:04:43 -0600

I have noticed the same and it seems to be an issue with FFmpeg 3.3 in macports. Activating ffmpeg @3.2.4_4+gpl2 solves the issue for me (both for my code and for your test program).

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Comments

I have the same problem, so, do you had fix it? Thx

cenah gravatar imagecenah ( 2017-11-13 01:56:10 -0600 )edit

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Asked: 2017-07-31 08:48:36 -0600

Seen: 1,052 times

Last updated: Jul 31 '17