1 The build script is to be fixed. 2 Right now it assumes that 32-bit MinGW is in the system path and 3 64-bit mingw is installed to c:\Apps\MinGW64. 4 5 It is important that gcc is used, not g++! 6 Otherwise the produced DLL will likely be dependent on libgcc_s_dw2-1.dll or similar DLL. 7 While we want to make the DLLs with minimum dependencies: Win32 libraries + msvcrt.dll. 8 9 ffopencv.c is really a C++ source, hence -x c++ is used. 10 11 How to update opencv_ffmpeg.dll and opencv_ffmpeg_64.dll when a new version of FFMPEG is release? 12 13 1. Install 32-bit MinGW + MSYS from 14 http://sourceforge.net/projects/mingw/files/Automated%20MinGW%20Installer/mingw-get-inst/ 15 Let's assume, it's installed in C:\MSYS32. 16 2. Install 64-bit MinGW. http://mingw-w64.sourceforge.net/ 17 Let's assume, it's installed in C:\MSYS64 18 3. Copy C:\MSYS32\msys to C:\MSYS64\msys. Edit C:\MSYS64\msys\etc\fstab, change C:\MSYS32 to C:\MSYS64. 19 20 4. Now you have working MSYS32 and MSYS64 environments. 21 Launch, one by one, C:\MSYS32\msys\msys.bat and C:\MSYS64\msys\msys.bat to create your home directories. 22 23 4. Download ffmpeg-x.y.z.tar.gz (where x.y.z denotes the actual ffmpeg version). 24 Copy it to C:\MSYS{32|64}\msys\home\<loginname> directory. 25 26 5. To build 32-bit ffmpeg libraries, run C:\MSYS32\msys\msys.bat and type the following commands: 27 28 5.1. tar -xzf ffmpeg-x.y.z.tar.gz 29 5.2. mkdir build 30 5.3. cd build 31 5.4. ../ffmpeg-x.y.z/configure --enable-w32threads 32 5.5. make 33 5.6. make install 34 5.7. cd /local/lib 35 5.8. strip -g *.a 36 37 6. Then repeat the same for 64-bit case. The output libs: libavcodec.a etc. need to be renamed to libavcodec64.a etc. 38 39 7. Then, copy all those libs to <opencv>\3rdparty\lib\, copy the headers to <opencv>\3rdparty\include\ffmpeg_. 40 41 8. Then, go to <opencv>\3rdparty\ffmpeg, edit make.bat 42 (change paths to the actual paths to your msys32 and msys64 distributions) and then run make.bat 43
