Shulou(Shulou.com)06/03 Report--

1) linux to view the opencv installation path and version number

View the opencv installation library under linux:

Pkg-config opencv-libs

View the installation version of opencv under linux:

Pkg-config opencv-modversion

View the opencv installation path under linux:

Find /-iname "* opencv*"

2) compile instruction

Create a library directory: mkdir install

Create a build directory: mkdir build

Enter the directory: cd build

Execute the generate Makefile:

Cmake-D WITH_CUDA=OFF\

-D CMAKE_BUILD_TYPE=Release\

-D CMAKE_INSTALL_PREFIX=cmake-D WITH_CUDA=OFF\

-D CMAKE_BUILD_TYPE=Release\

-D CMAKE_INSTALL_PREFIX=/home/packages/opencv/install\

-D WITH_IPP=OFF\

-D WITH_FFMPEG=ON\

-D BUILD_TESTS=OFF\

-D BUILD_PERF_TESTS=OFF\

-D INSTALL_PYTHON_EXAMPLES=OFF\

-D INSTALL_C_EXAMPLES=OFF\

-D PYTHON_EXECUTABLE=$ (which python)\

-D BUILD_EXAMPLES=OFF.. \

-D WITH_IPP=OFF\

-D WITH_FFMPEG=ON\

-D BUILD_TESTS=OFF\

-D BUILD_PERF_TESTS=OFF\

-D INSTALL_PYTHON_EXAMPLES=OFF\

-D INSTALL_C_EXAMPLES=OFF\

-D PYTHON_EXECUTABLE=$ (which python)\

-D BUILD_EXAMPLES=OFF..

Generate installation: make & & make install

Compilation exception

1) [98%] Linking CXX executable.. / bin/opencv_performance

.. /.. / lib/libopencv_highgui.so.2.4.9: undefined reference to `avcodec_alloc_frame'

.. /.. / lib/libopencv_highgui.so.2.4.9: undefined reference to `avcodec_encode_video'

Collect2: error: ld returned 1 exit status

Apps/haartraining/CMakeFiles/opencv_performance.dir/build.make:105: recipe for target 'bin/opencv_performance' failed

Make [2]: * * [bin/opencv_performance] Error 1

CMakeFiles/Makefile2:3388: recipe for target 'apps/haartraining/CMakeFiles/opencv_performance.dir/all' failed

Make [1]: * * [apps/haartraining/CMakeFiles/opencv_performance.dir/all] Error 2

Makefile:149: recipe for target 'all' failed

Make: * * [all] Error 2

Problem: undefined reference to `avcodec_alloc_frame'

Return null via grep-r "avcodec_alloc_frame" / query global text

The latest version of FFmpeg the implementation name of this function has been changed, download the ffmpeg-2.3.tar.bz2 source code to compile

2) ffmpeg-2.3.tar.bz2 has been compiled, but the generated libswresample.so.0 cannot be found. Copy the libswresample.so.0 to the / lib64 directory.

Usr/bin/ld: warning: libswresample.so.0, needed by / / home/dong/ffmpeg/ffmpeg-2.3/build/lib/libavcodec.so.55, not found (try using-rpath or-rpath-link)

/ / home/dong/ffmpeg/ffmpeg-2.3/build/lib/libavcodec.so.55: undefined reference to `swr_init@LIBSWRESAMPLE_0'

/ / home/dong/ffmpeg/ffmpeg-2.3/build/lib/libavcodec.so.55: undefined reference to `swr_close@LIBSWRESAMPLE_0'

/ / home/dong/ffmpeg/ffmpeg-2.3/build/lib/libavcodec.so.55: undefined reference to `swr_is_initialized@LIBSWRESAMPLE_0'

/ / home/dong/ffmpeg/ffmpeg-2.3/build/lib/libavcodec.so.55: undefined reference to `swr_free@LIBSWRESAMPLE_0'

/ / home/dong/ffmpeg/ffmpeg-2.3/build/lib/libavcodec.so.55: undefined reference to `swr_alloc@LIBSWRESAMPLE_0'

/ / home/dong/ffmpeg/ffmpeg-2.3/build/lib/libavcodec.so.55: undefined reference to `swr_convert@LIBSWRESAMPLE_0'

Collect2: error: ld returned 1 exit status

Apps/haartraining/CMakeFiles/opencv_performance.dir/build.make:105: recipe for target 'bin/opencv_performance' failed

Make [2]: * * [bin/opencv_performance] Error 1

CMakeFiles/Makefile2:3388: recipe for target 'apps/haartraining/CMakeFiles/opencv_performance.dir/all' failed

Make [1]: * * [apps/haartraining/CMakeFiles/opencv_performance.dir/all] Error 2

Makefile:149: recipe for target 'all' failed

Make: * * [all] Error

3) export PKG_CONFIG_PATH=/home/dong/opencv-2.4.9/install/lib/pkgconfig/;$PKG_CONFIG_PATH

Specifies that OpenCV first finds the compiled FFmpeg rather than the system's FFmpeg library

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