In my earlier post, I mentioned how I'd compiled OpenCV 3.4.9 using MingGW (32-bit) on Windows 10. In this post, I give the details of the changes I needed to make in order to build a working OCVWarp using this opencv.
Strangely enough, the reason for OCVWarp to silently exit for earlier builds, which were deemed successful on appveyor, was the presence of this line,
const bool askOutputType = argv[3][0] =='Y';
Removing the argv from this line and making it just
const bool askOutputType =0
made the build go to the next problem point, which is that OpenCV on Windows needs paths which have \ escaped. So, C:\\path\\to\\video.mp4 and so on. Fixed that with this hack of creating a function with switch / case, then the build works on Windows 10, but doesn't find the video file on Windows 7.
Also, to build with my compiled opencv, needed to specify the path to the link libraries, because otherwise it would link to the Visual Studio C libraries which were also present, and would cause linking errors. The easiest way I found to do this was to run the cmake gui, and choosing the Add Entry button to add target_link_libraries path to mingw's bin directory.
Then configure with MingGW Makefiles generator, followed by
cd build
make OCVWarp.bin
on the command-line, does the build properly. Interestingly, here the target name is case-sensitive :)
The pre-build dlls for OpenCV 3.4.3 which I had used for Appveyor builds have extremely limited support for output codecs. Probably they are built without ffmpeg support. So, if someone wants to build OCVWarp for x64 on Windows, it would be better to build OpenCV and then build OCVWarp rather than use the pre-built OpenCV.
Strangely enough, the reason for OCVWarp to silently exit for earlier builds, which were deemed successful on appveyor, was the presence of this line,
const bool askOutputType = argv[3][0] =='Y';
Removing the argv from this line and making it just
const bool askOutputType =0
made the build go to the next problem point, which is that OpenCV on Windows needs paths which have \ escaped. So, C:\\path\\to\\video.mp4 and so on. Fixed that with this hack of creating a function with switch / case, then the build works on Windows 10, but doesn't find the video file on Windows 7.
Also, to build with my compiled opencv, needed to specify the path to the link libraries, because otherwise it would link to the Visual Studio C libraries which were also present, and would cause linking errors. The easiest way I found to do this was to run the cmake gui, and choosing the Add Entry button to add target_link_libraries path to mingw's bin directory.
Then configure with MingGW Makefiles generator, followed by
cd build
make OCVWarp.bin
on the command-line, does the build properly. Interestingly, here the target name is case-sensitive :)
The pre-build dlls for OpenCV 3.4.3 which I had used for Appveyor builds have extremely limited support for output codecs. Probably they are built without ffmpeg support. So, if someone wants to build OCVWarp for x64 on Windows, it would be better to build OpenCV and then build OCVWarp rather than use the pre-built OpenCV.
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