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• OpenCV ffmpeg DLL not loaded when running app on Windows 7, works on 8 and 10

  2 novembre 2016, par David G.

  I need to maintain a desktop app written in C++, using Qt and OpenCV for some video processing. As far as I understood, the decoding part of OpenCV is delegated to ffmpeg in a separate DLL for licensing reasons.

  The development environment is on Windows 10, using QT Creator and MSVC12 64-bit as compiler. OpenCV version is 3.0, the official distribution. Here, everything runs fine, I am able to decode a video using VideoCapture::open().

  Issues arise when I try to run the application in a standalone fashion with all the required DLLs in the same folder as the .exe file. All cases below are 64-bit OSes.

  On a Windows 10 computer, not the same as the developement machine and no developer libraries present, the video decoding works fine. I have tested on a Windows 8 machine as well, no issues so far.

  On Windows 7, the things get tricky. The same video files that successfully load during the previous tests are not recognized by the app at all i.e. the isOpened call on VideoCapture returns false. For further testing, I stripped the opencv_ffmpeg300_64.dll file to narrow down the issue on Windows 10 and 8 ; as expected, without this DLL the app is no more able to open the same video files.

  It seems that the DLL is simply not recognized on Windows 7.

  Edit : Further investigation using Process Explorer clearly shows that the aforementioned DLL is not loaded when the app runs on Windows 7.

  • Is there something specific about how Windows 7 manages the DLL path resolution and eventual security measures ? Seems normal that the first search location is the same folder as the executable, which is the case here.

  I have tried to trace using WinApiOverride32, with no results.

• OpenCV ffmpeg DLL not loaded when running app on Windows 7, works on 8 and 10

  4 avril 2018, par David G.

  I need to maintain a desktop app written in C++, using Qt and OpenCV for some video processing. As far as I understood, the decoding part of OpenCV is delegated to ffmpeg in a separate DLL for licensing reasons.

  The development environment is on Windows 10, using QT Creator and MSVC12 64-bit as compiler. OpenCV version is 3.0, the official distribution. Here, everything runs fine, I am able to decode a video using VideoCapture::open().

  Issues arise when I try to run the application in a standalone fashion with all the required DLLs in the same folder as the .exe file. All cases below are 64-bit OSes.

  On a Windows 10 computer, not the same as the developement machine and no developer libraries present, the video decoding works fine. I have tested on a Windows 8 machine as well, no issues so far.

  On Windows 7, the things get tricky. The same video files that successfully load during the previous tests are not recognized by the app at all i.e. the isOpened call on VideoCapture returns false. For further testing, I stripped the opencv_ffmpeg300_64.dll file to narrow down the issue on Windows 10 and 8 ; as expected, without this DLL the app is no more able to open the same video files.

  It seems that the DLL is simply not recognized on Windows 7.

  Edit : Further investigation using Process Explorer clearly shows that the aforementioned DLL is not loaded when the app runs on Windows 7.

  • Is there something specific about how Windows 7 manages the DLL path resolution and eventual security measures ? Seems normal that the first search location is the same folder as the executable, which is the case here.

  I have tried to trace using WinApiOverride32, with no results.

• “only position independent executables (PIE) are supported”

  3 juin 2015, par Karthikeyan

  I am using FFMPEG support library to convert bunch of images to video. It works fine on earlier version of the lollipop. But in the lollipop it generates the following error. ***error: only position independent executables (PIE) are supported.*** I know the PIE Security restrictions has been changed in lollipop, but i don’t know how to fix it.

  From my knowledge it may have two possible solutions,

  either

  we need to relocate the FFMPEG library assets to the SDCard and we have to refer them from our coding, if this is the answer what are all the steps to be followed ?

  or

  Is there any update in the FFMPEG library for android lollipop.

  If both are wrong can you provide me with the proper solution.

  Many thanks...

  Here is my code

     try {
  
              String[] ffmpegCommand = {"/data/data/com.mobvcasting.mjpegffmpeg/ffmpeg", "-r", ""+p.getPreviewFrameRate(), "-b", "1000000", "-vcodec", "mjpeg", "-i", 
  
                      Environment.getExternalStorageDirectory().getPath() + "/req_images/frame_%05d.jpg", Environment.getExternalStorageDirectory().getPath() + "/req_images/video.mov"};
  
  
  
              ffmpegProcess = new ProcessBuilder(ffmpegCommand).redirectErrorStream(true).start();            
  
  
  
              OutputStream ffmpegOutStream = ffmpegProcess.getOutputStream();
  
              BufferedReader reader = new BufferedReader(new InputStreamReader(ffmpegProcess.getInputStream()));
  
  
  
              String line;
  
  
  
              Log.v(LOGTAG,"***Starting FFMPEG***");
  
              while ((line = reader.readLine()) != null)
  
              {
  
                  Log.v(LOGTAG,"***"+line+"***");
  
              }
  
              Log.v(LOGTAG,"***Ending FFMPEG***");
  
  
  
  
  
          } catch (IOException e) {
  
              e.printStackTrace();
  
          }
  
  
  
          if (ffmpegProcess != null) {
  
              ffmpegProcess.destroy();        
  
          }