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• Makefile for c++ program cannot be compiled properly

  20 mars 2017, par Wei

  I am quite new to c++ Makefile. Recently, I am trying to re-implement the dense trajectory algorithm introduced by this paper : https://lear.inrialpes.fr/people/wang/dense_trajectories

  However, I was struggling with Makefile that they provided for quite a while. The Makefile is as follows :

  # set the binaries that have to be built
  
  TARGETS := DenseTrack Video
  
  
  
  # set the build configuration set 
  
  BUILD := release
  
  #BUILD := debug
  
  
  
  # set bin and build dirs
  
  BUILDDIR := .build_$(BUILD)
  
  BINDIR := $(BUILD)
  
  
  
  # libraries 
  
  LDLIBS = $(addprefix -l, $(LIBS) $(LIBS_$(notdir $*)))
  
  LIBS := \
  
      opencv_core opencv_highgui opencv_video opencv_imgproc \
  
      avformat avdevice avutil avcodec swscale
  
  
  
  # set some flags and compiler/linker specific commands
  
  CXXFLAGS = -pipe -D __STDC_CONSTANT_MACROS -D STD=std -Wall $(CXXFLAGS_$(BUILD)) -I. -I/usr/local/include -I/home/wei/ffmpeg_build/include
  
  CXXFLAGS_debug := -ggdb
  
  CXXFLAGS_release := -O3 -DNDEBUG -ggdb
  
  LDFLAGS = -L/usr/local/lib -L/home/wei/ffmpeg_build/lib -pipe -Wall $(LDFLAGS_$(BUILD))
  
  LDFLAGS_debug := -ggdb
  
  LDFLAGS_release := -O3 -ggdb
  
  
  
  include make/generic.mk

  I can verify that my opencv2.4.2 and ffmpeg5.4.0 are successfully installed in Ubuntu 16.04, by running an example using those two libraries.

  For opencv :
  The lib path is : /usr/local/lib

  libavcodec.a                   libopencv_gpu.so.2.4   
  
      libopencv_photo.so.2.4
  
  libavdevice.a                  libopencv_gpu.so.2.4.2        libopencv_photo.so.2.4.2
  
  libavfilter.a                  libopencv_highgui.so          libopencv_stitching.so
  
  libavformat.a                  libopencv_highgui.so.2.4      libopencv_stitching.so.2.4
  
  libavutil.a                    libopencv_highgui.so.2.4.2    libopencv_stitching.so.2.4.2
  
  libopencv_calib3d.so           libopencv_imgproc.so          libopencv_ts.so
  
  libopencv_calib3d.so.2.4       libopencv_imgproc.so.2.4      libopencv_ts.so.2.4
  
  libopencv_calib3d.so.2.4.2     libopencv_imgproc.so.2.4.2    libopencv_ts.so.2.4.2
  
  libopencv_contrib.so           libopencv_legacy.so           libopencv_video.so
  
  libopencv_contrib.so.2.4       libopencv_legacy.so.2.4       libopencv_video.so.2.4
  
  libopencv_contrib.so.2.4.2     libopencv_legacy.so.2.4.2     libopencv_video.so.2.4.2
  
  libopencv_core.so              libopencv_ml.so               libopencv_videostab.so
  
  libopencv_core.so.2.4          libopencv_ml.so.2.4           libopencv_videostab.so.2.4
  
  libopencv_core.so.2.4.2        libopencv_ml.so.2.4.2         libopencv_videostab.so.2.4.2
  
  libopencv_features2d.so        libopencv_nonfree.so          libpostproc.a
  
  libopencv_features2d.so.2.4    libopencv_nonfree.so.2.4      libswresample.a
  
  libopencv_features2d.so.2.4.2  libopencv_nonfree.so.2.4.2    libswscale.a
  
  libopencv_flann.so             libopencv_objdetect.so        pkgconfig
  
  libopencv_flann.so.2.4         libopencv_objdetect.so.2.4    python2.7
  
  libopencv_flann.so.2.4.2       libopencv_objdetect.so.2.4.2  python3.5
  
  libopencv_gpu.so               libopencv_photo.so

  The include path is : usr/local/include :

  libavcodec   libavfilter  libavutil    libswresample  opencv
  
  libavdevice  libavformat  libpostproc  libswscale     opencv2

  For ffmpeg :
  The lib path is : /home/user/ffmpeg_build/lib

  libavcodec.a   libavfilter.a  libavutil.a   libfdk-aac.la  libswresample.a  libx265.a
  
  libavdevice.a  libavformat.a  libfdk-aac.a  libpostproc.a  libswscale.a     pkgconfig

  The include path is : /home/user/ffmpeg/include

  fdk-aac     libavdevice  libavformat  libpostproc    libswscale     x265.h
  
  libavcodec  libavfilter  libavutil    libswresample  x265_config.h

  So when I make it with Makefile, I did not get error but it seems linking is working properly, nor is the compiled output.

  I tried to directly compile with g++ command.

  sudo g++ -o Video -pipe -D __STDC_CONSTANT_MACROS -D STD=std -Wall -I. -I/usr/local/include -O3 -DNDEBUG -ggdb -L/usr/local/lib -lopencv_core -lopencv_highgui -lopencv_video -lopencv_imgproc -lavformat -lavdevice -lavutil -lavcodec -lswscale *.h Video.cpp

  However,it returns errors as :

  /tmp/ccjYmwI4.o: In function `main':
  
  /home/wei/Documents/dt/dense_trajectory_release_v1.2/Video.cpp:33: undefined reference to `cvCreateFileCapture'
  
  /home/wei/Documents/dt/dense_trajectory_release_v1.2/Video.cpp:48: undefined reference to `cvQueryFrame'
  
  /home/wei/Documents/dt/dense_trajectory_release_v1.2/Video.cpp:57: undefined reference to `cvCopy'
  
  /home/wei/Documents/dt/dense_trajectory_release_v1.2/Video.cpp:60: undefined reference to `cvShowImage'
  
  /home/wei/Documents/dt/dense_trajectory_release_v1.2/Video.cpp:61: undefined reference to `cvWaitKey'
  
  /home/wei/Documents/dt/dense_trajectory_release_v1.2/Video.cpp:53: undefined reference to `cvCreateImage'
  
  /home/wei/Documents/dt/dense_trajectory_release_v1.2/Video.cpp:70: undefined reference to `cvDestroyWindow'
  
  /home/wei/Documents/dt/dense_trajectory_release_v1.2/Video.cpp:41: undefined reference to `cvNamedWindow'
  
  collect2: error: ld returned 1 exit status

  I have been working on this issue for several days. Any help or suggestions would be really appreciated.

  Thanks

• I only have two presets for ffmpeg x264 in ubuntu 11.04

  17 octobre 2012, par Mr X Colombia

  I'me trying to install (compile) ffmpeg for ubuntu 11.04 by following this guide :

  https://ffmpeg.org/trac/ffmpeg/wiki/UbuntuCompilationGuide

  Overall it works. Except for some errors with checkinstall due to numbering, which i resolved with this :

  http://judsonsnotes.com/notes/index.php?option=com_content&view=section&layout=blog&id=3&Itemid=54&limitstart=40

  I'd say it was installed ok.

  But when trying to encode some video with -vpre lossless_slow i get this error :

  File for preset lossless_slow not found.

  And in fact it doesn't exists. All i have is this :

  /usr/local/share/ffmpeg:
  
  libvpx-1080p50_60.ffpreset
  
  libvpx-1080p.ffpreset
  
  libvpx-360p.ffpreset
  
  libvpx-720p50_60.ffpreset
  
  libvpx-720p.ffpreset
  
  libx264-ipod320.ffpreset
  
  libx264-ipod640.ffpreset

  Where are all the other presets ? in google usually people have many more presets than i do. What did i do wrong ?

  From this post i'd say that they shopuld be there : http://git.videolan.org/?p=ffmpeg.git ;a=commit ;h=4b82e3cedcfc9871671bb613cd979de6995dcb4e

  Thanks a lot !

• 1080p video on Beagle

  10 février 2010, par Mans — Multimedia

  FOSDEM 2010 is over, and I’d like to call it a success for FFmpeg. The 11-man strong delegation showed the stunned audience a smashing demo featuring a Beagle-powered video wall. It looked like this :

  The people who pulled this off look like this :