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• Creating a shared library that statically includes ffmpeg

  10 octobre 2017, par El Sampsa

  I’m having hard time trying to create a shared library that has ffmpeg libraries "baked in" as static ones.

  Consider the following directory schema :

  include/
  
    my own .h files
  
    ext/
  
      ffmpeg .h files
  
  lib/
  
    libav*.a archive files (softlinks to the actual .a files)
  
    libValkka.so (my shared library)
  
  test/
  
    mytest.cpp
  
  bin/
  
    (binaries appear here)

  I’ve come a long way (see Including objects to a shared library from a C++ archive (.a) ) and the library compiles ok with this : ([STUFF] has been omitted for brevity)

  /usr/bin/c++ -fPIC -std=c++14 -pthread -Iinclude/ext -I/usr/include/libdrm -g -shared -Wl,-soname,libValkka.so -o lib/libValkka.so CMakeFiles/Valkka.dir/src/avthread.cpp.o CMakeFiles/Valkka.dir/src/opengl.cpp.o CMakeFiles/Valkka.dir/src/openglthread.cpp.o [STUFF] CMakeFiles/Valkka.dir/src/filters.cpp.o -lX11 -lGLEW -lGLU -lGL -Wl,—allow-multiple-definition -Wl,-Bsymbolic -Wl,—whole-archive -Wreorder lib/libavdevice.a lib/libavfilter.a lib/libavformat.a lib/libavcodec.a lib/libavutil.a lib/libswscale.a lib/libswresample.a -Wl,—no-whole-archive

  However, when creating executables - their source code does not use any ffmpeg api (just my own api) - with :

  c++ -std=c++14 -pthread -Iinclude -Iinclude/ext -Llib test/mytest.cpp -lValkka -g -o bin/mytest

  I get a hoard of errors about missing ffmpeg dependencies. Not everything is missing, just some weird stuff :

  lib/libValkka.so: undefined reference to `pa_stream_get_index'
  
  lib/libValkka.so: undefined reference to `deflateInit_'
  
  lib/libValkka.so: undefined reference to `pa_stream_get_state'
  
  lib/libValkka.so: undefined reference to `lzma_stream_decoder'
  
  lib/libValkka.so: undefined reference to `BZ2_bzDecompress'
  
  lib/libValkka.so: undefined reference to `vaInitialize'
  
  lib/libValkka.so: undefined reference to `pa_stream_unref'
  
  lib/libValkka.so: undefined reference to `deflateInit2_'
  
  lib/libValkka.so: undefined reference to `snd_pcm_close'
  
  ...
  
  lib/libValkka.so: undefined reference to `vaGetDisplayDRM'
  
  lib/libValkka.so: undefined reference to `vaMaxNumEntrypoints'
  
  lib/libValkka.so: undefined reference to `uncompress'
  
  lib/libValkka.so: undefined reference to `pa_stream_drop'
  
  lib/libValkka.so: undefined reference to `pa_context_connect'
  
  lib/libValkka.so: undefined reference to `FT_Get_Kerning'
  
  lib/libValkka.so: undefined reference to `ass_free_track'
  
  lib/libValkka.so: undefined reference to `pa_operation_unref'
  
  lib/libValkka.so: undefined reference to `FT_Stroker_Done'
  
  lib/libValkka.so: undefined reference to `vaTerminate'
  
  lib/libValkka.so: undefined reference to `ass_new_track'
  
  lib/libValkka.so: undefined reference to `jack_client_close'
  
  ...
  
  lib/libValkka.so: undefined reference to `xcb_xfixes_query_version'
  
  lib/libValkka.so: undefined reference to `xcb_shape_rectangles'
  
  lib/libValkka.so: undefined reference to `pa_mainloop_free'
  
  lib/libValkka.so: undefined reference to `snd_device_name_hint'
  
  lib/libValkka.so: undefined reference to `vaCreateImage'
  
  lib/libValkka.so: undefined reference to `vaBeginPicture'
  
  lib/libValkka.so: undefined reference to `DtsSetColorSpace'
  
  lib/libValkka.so: undefined reference to `vaDestroyConfig'
  
  lib/libValkka.so: undefined reference to `pa_stream_writable_size'
  
  lib/libValkka.so: undefined reference to `snd_pcm_hw_params_get_buffer_size_max'
  
  lib/libValkka.so: undefined reference to `ass_read_file'

  This is pretty frustrating, especially when I can see that those names are included in the shared library..!

  nm lib/libValkka.so | grep "vaBeginPicture"

  gives

  U vaBeginPicture

  etc. I thought it might be a problem regarding the dependency order the archive .a files, and also tried with :

  ..... -Wl,—allow-multiple-definition -Wl,-Bsymbolic -Wl,—start-group -Wl,—whole-archive -Wreorder lib/libavdevice.a lib/libavfilter.a lib/libavformat.a lib/libavcodec.a lib/libavutil.a lib/libswscale.a lib/libswresample.a -Wl,—no-whole-archive -Wl,—end-group

  But the problem persists.

  I have succesfully created a shared library that does not "bake in" those .a archives, i.e. that just depends dynamically on ffmpeg libraries, and there are no such problems.

  I am baffled.. Have I misunderstood something fundamental, forgot some annoying linked option, or both ? Help appreciated !

• Evolution #2050 : site vide au début

  31 août 2011, par cedric -

  et également le ticket le plus ancien #1881

• Evolution #2050 : site vide au début

  31 août 2011, par cedric -

  voir aussi #2047 qui est une proposition de solution