C++ – Ffmpeg linking problems using CMake

I'm writing an application containig 2 internal libraries and depends on more 2 external libraries (ffmpeg and opencv). I'm also using CMake to produce UNIX makefiles. And the problem is when i'm trying to build sources, it compiles but don't link with ffmpeg at all and the next output the linker gives:

../../Decoder/libDecoder.a(ConverterAVFrameToRGB.cpp.o): In function `FaceVideo::ConverterAVFrameToRGB::to_rgb_conversion(std::vector<AVFrame*, std::allocator<AVFrame*> >&, int, int, int)':
ConverterAVFrameToRGB.cpp:(.text+0x990): undefined reference to `av_frame_free'
../../Decoder/libDecoder.a(FfmpegDecoder.cpp.o): In function `FaceVideo::FfmpegDecoder::destroy()':
FfmpegDecoder.cpp:(.text+0xa30): undefined reference to `av_frame_free'
../../Decoder/libDecoder.a(FfmpegDecoder.cpp.o): In function `FaceVideo::FfmpegDecoder::decode_next_chunk(int)':
FfmpegDecoder.cpp:(.text+0xb6b): undefined reference to `av_frame_clone'
FfmpegDecoder.cpp:(.text+0xc13): undefined reference to `av_frame_free'
../../Decoder/libDecoder.a(FfmpegEncoder.cpp.o): In function `FaceVideo::FfmpegEncoder::destroy()':
FfmpegEncoder.cpp:(.text+0x132): undefined reference to `avcodec_free_frame'
../../Decoder/libDecoder.a(FfmpegEncoder.cpp.o): In function `FaceVideo::FfmpegEncoder::encode()':
FfmpegEncoder.cpp:(.text+0x4c4): undefined reference to `avcodec_encode_video2'
FfmpegEncoder.cpp:(.text+0x592): undefined reference to `avcodec_encode_video2'
../../Decoder/libDecoder.a(FrameSaver.cpp.o): In function `FaceVideo::FrameSaver::saver(std::vector<AVFrame*, std::allocator<AVFrame*> >&, int, int, int)':
FrameSaver.cpp:(.text+0x869): undefined reference to `av_frame_free'
collect2: ld returned 1 exit status

That's excatly what i don't want to see.

There are three Cmake files: two for internal libraries (use

add_library(Decoder ${SOURCES_DECODER})
             and 
add_library(Detector ${SOURCES_DETECTOR})

in them) and one for main executable (use

add_executable(Tool ${SOURCES_TOOL})
             and
target_link_libraries (Tool Decoder avutil avcodec swscale avformat Detector ${OpenCV_LIBS})

in it).

As far as i understand from CMake manuals and examples, this should make linker link this libraries together, but no effect.

I've been trying lot of things such as:
1) Adding link_directories() with path to libraries (/usr/lib/x86_64-linux-gnu/ for me) wherever it's possile, nothing changed.
2) Linking every library separately, i mean i tried do something like this in my internal libraries CMake files: target_link_libraries (Decoder avutil avcodec swscale avformat). And then link library together into my Tool CMake file: target_link_libraries (Tool Decoder Detector).
3) Editing output makefiles.
4) Compiling simple one-file application just to test whether i can do it or not. I can. g++ -lavcodec -o out mysource.cpp works perfectly.
5) Compling ffmpeg manually and installing it.

The fact is i realy don't know what should i do. I have no idea. And i would very appreciate your every answer.

UPD1:
Output when CMAKE_VERBOSE_MAKEFILE is set

!
/usr/bin/c++ -march=x86-64 -Wall -fPIC -pthread -std=c++0x -D__STDC_CONSTANT_MACROS -march=x86-64 -fPIC CMakeFiles/FaceDetectorTool.dir/home/anton/Programming/facevideo/branches/Stream_Prototype/src/tools/FaceDetectorTool/facedetector.cpp.o -o FaceDetectorTool -rdynamic ../../Detector/libDetector.a ../../Decoder/libDecoder.a -lavutil -lavcodec -lswscale -lavformat /usr/local/lib/libopencv_videostab.so.2.4.7 /usr/local/lib/libopencv_video.so.2.4.7 /usr/local/lib/libopencv_ts.a /usr/local/lib/libopencv_superres.so.2.4.7 /usr/local/lib/libopencv_stitching.so.2.4.7 /usr/local/lib/libopencv_photo.so.2.4.7 /usr/local/lib/libopencv_ocl.so.2.4.7 /usr/local/lib/libopencv_objdetect.so.2.4.7 /usr/local/lib/libopencv_nonfree.so.2.4.7 /usr/local/lib/libopencv_ml.so.2.4.7 /usr/local/lib/libopencv_legacy.so.2.4.7 /usr/local/lib/libopencv_imgproc.so.2.4.7 /usr/local/lib/libopencv_highgui.so.2.4.7 /usr/local/lib/libopencv_gpu.so.2.4.7 /usr/local/lib/libopencv_flann.so.2.4.7 /usr/local/lib/libopencv_features2d.so.2.4.7 /usr/local/lib/libopencv_core.so.2.4.7 /usr/local/lib/libopencv_contrib.so.2.4.7 /usr/local/lib/libopencv_calib3d.so.2.4.7 -ldl -lm -lpthread -lrt /usr/local/lib/libopencv_nonfree.so.2.4.7 /usr/local/lib/libopencv_ocl.so.2.4.7 /usr/local/lib/libopencv_gpu.so.2.4.7 /usr/local/lib/libopencv_photo.so.2.4.7 /usr/local/lib/libopencv_objdetect.so.2.4.7 /usr/local/lib/libopencv_legacy.so.2.4.7 /usr/local/lib/libopencv_video.so.2.4.7 /usr/local/lib/libopencv_ml.so.2.4.7 /usr/local/lib/libopencv_calib3d.so.2.4.7 /usr/local/lib/libopencv_features2d.so.2.4.7 /usr/local/lib/libopencv_highgui.so.2.4.7 /usr/local/lib/libopencv_imgproc.so.2.4.7 /usr/local/lib/libopencv_flann.so.2.4.7 /usr/local/lib/libopencv_core.so.2.4.7 -Wl,-rpath,/usr/local/lib

UPD2
Cmake example looks like that.

cmake_minimum_required (VERSION 2.8)
project (Decoder)
include(../CMakeInit.cmake)
include_directories(${FFMPEG_INCLUDE_DIR})
include_directories(${Stream_Facevideo_SOURCE_DIR}/../src/kernel/decoder/)
include_directories(${Stream_Facevideo_SOURCE_DIR}/../src/kernel/stuff/)
set(SOURCES_VIDEODECODER
            *sources*
  )

if(WINDOWS)
    set(SOURCES_VIDEODECODER    ${SOURCES_VIDEODECODER} 
            *headers*                           
    )
endif(WINDOWS)

set (SOURCES_DECODER
    ${SOURCES_VIDEODECODER}
)

add_library(Decoder ${SOURCES_DECODER})
link_directories("/usr/lib/x86_64-linux-gnu/")
target_link_libraries(Decoder swscale avformat avcodec avutil)