Re: [Mingw-cross-env-list] Undefined Reference errors when linking

[Mark Brand]

> > > Now I ned to convince ffmpeg to link with my program:
> > > http://granjow.net/uploads/temp/make3.txt
> > > What could I do here?
> >
> > I don't anything useful in your make3.txt. It stops after 80%.
>
> fixed. codepad.org did not allow more text ;)
> I used VERBOSE=1, V=1 seemed to have no effect, or am I wrong?

> /home/user/mingw-cross-env/usr/bin/i686-pc-mingw32-g++  -O3 -DNDEBUG    
> -Wl,--whole-archive CMakeFiles/PhenoCam.dir/objects.a -Wl,--no-whole-archive  
> -o PhenoCam.exe -Wl,--out-implib,libPhenoCam.dll.a 
> -Wl,--major-image-version,0,--minor-image-version,0  libproject.a 
> lib/libgeometry.a -Wl,-Bstatic -lQtGui -lpng -ljpeg -ltiff -lmng -Wl,-Bdynamic 
> -limm32 -lwinmm -Wl,-Bstatic -lQtTest -lQtCore -lz -Wl,-Bdynamic -lws2_32 
> -Wl,-Bstatic -lqjson -Wl,-Bdynamic -ltiff -llzma -lmng -llcms -lmp3lame -lspeex 
> -lvorbis -lspeexdsp -lxvidcore -lx264 -lvpx -lwinmm core/libcorelib.a 
> lib/libgeometry.a lib/libcsv.a -Wl,-Bstatic -lQtGui -lpng -ljpeg -ltiff -lmng 
> -Wl,-Bdynamic -limm32 lib/libmemInfo.a lib/libvideo.a -lavformat -lavcodec 
> -lavutil -lwinmm -Wl,-Bstatic -lQtTest -lQtCore -lz -Wl,-Bdynamic -lws2_32 
> -lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid 
> -lcomdlg32 -ladvapi32
> lib/libvideo.a(readVideo.c.obj):readVideo.c:(.text+0x400): undefined reference 
> to `_sws_getContext'
> lib/libvideo.a(readVideo.c.obj):readVideo.c:(.text+0x47f): undefined reference 
> to `_sws_freeContext'
> lib/libvideo.a(readVideo.c.obj):readVideo.c:(.text+0x60d): undefined reference 
> to `_sws_scale'
> lib/libvideo.a(readVideo.c.obj):readVideo.c:(.text+0xa46): undefined reference 
> to `_sws_getContext'
> lib/libvideo.a(readVideo.c.obj):readVideo.c:(.text+0xa74): undefined reference 
> to `_sws_scale'
> lib/libvideo.a(writeVideo.c.obj):writeVideo.c:(.text+0x23a): undefined 
> reference to `_sws_freeContext'
> lib/libvideo.a(writeVideo.c.obj):writeVideo.c:(.text+0x290): undefined 
> reference to `_sws_getContext'
> lib/libvideo.a(writeVideo.c.obj):writeVideo.c:(.text+0x14ed): undefined 
> reference to `_sws_scale'
> lib/libvideo.a(writeVideo.c.obj):writeVideo.c:(.text+0x17bf): undefined 
> reference to `_sws_freeContext'
> /home/user/mingw-cross-env/usr/lib/gcc/i686-pc-mingw32/4.6.2/../../../../i686-pc-mingw32/lib/libavformat.a(avisynth.o):avisynth.c:(.text+0x6b):
>  undefined reference to address@hidden'
> /home/user/mingw-cross-env/usr/lib/gcc/i686-pc-mingw32/4.6.2/../../../../i686-pc-mingw32/lib/libavformat.a(avisynth.o):avisynth.c:(.text+0x88):
>  undefined reference to address@hidden'
> /home/user/mingw-cross-env/usr/lib/gcc/i686-pc-mingw32/4.6.2/../../../../i686-pc-mingw32/lib/libavformat.a(avisynth.o):avisynth.c:(.text+0x90):
>  undefined reference to address@hidden'
<snip>

You need to link to the libraries that supply these symbols. Since 
ffmpeg doesn't come with pkg-config support, I'm afraid you have to 
manually figure out which libraries to link to.

You can get an idea of what you need by looking at the package 
dependency (DEP) list in ffmpeg.mk.

Start by adding "-lavfilter -lswscale". Then see what's still missing 
and add those libraries. Repeat until finished.

Mark