Source code:
#include <iostream>
#include <opencv2/videoio.hpp>
#include <opencv2/core/utils/logger.hpp>
int main(int argc, char *argv[])
{
cv::utils::logging::setLogLevel(cv::utils::logging::LOG_LEVEL_VERBOSE);
cv::VideoWriter writer;
if (!writer.open("hello.mp4", cv::VideoWriter::fourcc('M', 'P', '4', 'V'), 25, cv::Size(100, 100))) {
std::cerr << argv[0] << ": cannot open" << std::endl;
return -1;
}
return 0;
}
Output:
[DEBUG:0@0.001] global /builddir/build/BUILD/opencv-4.5.5/modules/videoio/src/videoio_registry.cpp (197) VideoBackendRegistry VIDEOIO: Builtin backends(8): FFMPEG(1000); GSTREAMER(990); INTEL_MFX(980); V4L2(970); CV_IMAGES(960); CV_MJPEG(950); FIREWIRE(940); UEYE(930)
[DEBUG:0@0.001] global /builddir/build/BUILD/opencv-4.5.5/modules/videoio/src/videoio_registry.cpp (221) VideoBackendRegistry VIDEOIO: Available backends(8): FFMPEG(1000); GSTREAMER(990); INTEL_MFX(980); V4L2(970); CV_IMAGES(960); CV_MJPEG(950); FIREWIRE(940); UEYE(930)
[ INFO:0@0.001] global /builddir/build/BUILD/opencv-4.5.5/modules/videoio/src/videoio_registry.cpp (223) VideoBackendRegistry VIDEOIO: Enabled backends(8, sorted by priority): FFMPEG(1000); GSTREAMER(990); INTEL_MFX(980); V4L2(970); CV_IMAGES(960); CV_MJPEG(950); FIREWIRE(940); UEYE(930)
[ INFO:0@0.001] global /builddir/build/BUILD/opencv-4.5.5/modules/videoio/src/backend_plugin.cpp (369) getPluginCandidates VideoIO plugin (FFMPEG): glob is 'libopencv_videoio_ffmpeg*.so', 1 location(s)
[ INFO:0@0.008] global /builddir/build/BUILD/opencv-4.5.5/modules/videoio/src/backend_plugin.cpp (379) getPluginCandidates - /lib64: 0
[ INFO:0@0.008] global /builddir/build/BUILD/opencv-4.5.5/modules/videoio/src/backend_plugin.cpp (383) getPluginCandidates Found 0 plugin(s) for FFMPEG
[ WARN:0@0.016] global /builddir/build/BUILD/opencv-4.5.5/modules/videoio/src/cap_gstreamer.cpp (2180) open OpenCV | GStreamer warning: cannot link elements
MFX: Can't initialize session
[ INFO:0@0.016] global /builddir/build/BUILD/opencv-4.5.5/modules/videoio/src/cap_images.cpp (282) icvExtractPattern Pattern: hello.mp%01d @ 4
./a.out: cannot open
Fedora Linux. opencv-4.5.5-5.fc36.src.rpm
Is this the wrong library in the fedora repositories?