Ubuntu14.04 64位系统下安装python3.4对应的opencv3.0报错recompile with -fPIC 的解决办法

之前的Ubuntu14.04 64位系统下安装了ffmpeg，后来由于需要使用安装在python3.4环境下可以使用的python视觉库opencv3.0，下面是安装过程中遇到的一些问题。

首先。

1、对于windows7 64位下安装opencv3.0可以参考本人的这篇文章：Windows7 64位+python3.4环境下安装opencv3.0的方法

2、对于Ubuntu 14.04 64位环境下安装opencv3.0可以参考这篇文章：Ubuntu14.04 64位+Python3.4环境下安装opencv3.0的方法。

这里之所以再次提出为什么要在Ubuntu环境下安装opencv3.0呢？似乎看上去与“2”重复了啊，其实不是，由于各种实际项目开发问题，往往我们在安装opencv3.0的时候，环境已经不是如“2”中所说的纯净环境了，比如已经安装了ffmpeg，这时候会报如下错误：

[ 38%] Building CXX objectmodules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_ffmpeg.cpp.o

Linking CXX shared library../../lib/libopencv_videoio.so

/usr/bin/ld: cannot find -lavcodec

/usr/bin/ld:/usr/local/lib/libavutil.a(log.o): relocation R_X86_64_32 against`.rodata.str1.1' can not be used when making a shared object; recompile with-fPIC

/usr/local/lib/libavutil.a: error addingsymbols: Bad value

collect2: error: ld returned 1 exit status

make[2]: ***[lib/libopencv_videoio.so.3.0.0] Error 1

make[1]: ***[modules/videoio/CMakeFiles/opencv_videoio.dir/all] Error 2

make: *** [all] Error 2

因此，我们的目的就是如何在环境中已经安装ffmpeg的基础上能够成功安装opencv3.0。

我的解决过程如下：

步骤1:由于我的环境中ffmpeg是通过下载源码后自己编译生成，因此先进入到ffmpeg的目录，然后执行如下命令来卸载ffmpeg

sudo make uninstall

步骤2：执行如下脚本

 #!/bin/bash
 sudo apt-get update
 sudo apt-get install python3-setuptools python3-dev -y
 sudo easy_install3 pip
 pip3 install numpy

 sudo apt-get install build-essential -y
 sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev -y

 cd ~
 wget https://github.com/Itseez/opencv/archive/3.0.0.zip
 #注意这里不是 cd 3.0.0  , 而是 cd opencv-3.0.0
 unzip 3.0.0.zip && cd opencv-3.0.0
 mkdir build && cd build

 cmake -D CMAKE_BUILD_TYPE=Release \
 -D CMAKE_INSTALL_PREFIX=/usr/local  \
 PYTHON3_EXECUTABLE=/usr/bin/python3 \
 PYTHON_INCLUDE_DIR=/usr/include/python3.4 \
 PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.4m.so \
 PYTHON3_NUMPY_INCLUDE_DIRS=/usr/local/lib/python3.4/dist-packages/numpy/core/include ..

 # make -j [N] :表示在那个一时间内进行编译的任务数 ，如果-j 后面不跟任何数字，则不限制处理器并行编译的任务数,现在发现直接用make -j4 安装会失败
 #所以还是用 make -j1 成功了
 make -j1
 sudo make install

成功。

注意：一定要记得在执行完 上述脚本中第25行的 "make -j1" 后，要记得执行 "sudo make install"。

验证安装成功的方法是：

执行如下命令进入python3交互环境

python3

执行如下命令

import cv2

如果没有输出，表明opencv3.0安装成功

这里附上另一个解决办法给大家参考，希望给大家一些启示。但是对于我而言，并没有成功。

原文地址：http://stackoverflow.com/questions/28960944/opencv-installation-error-ubuntu

opencv installation error ubuntu

up vote 1 down vote favorite

I'm trying to install opencv to my Ubuntu 14.04 machine using the documentation provided in http://docs.opencv.org/doc/tutorials/introduction/linux_install/linux_install.html#linux-installation However, during the compilation process I get the following error. Linking CXX shared library ../../lib/libopencv_videoio.so /usr/bin/ld: /usr/local/lib/libavcodec.a(avpacket.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC /usr/local/lib/libavcodec.a: error adding symbols: Bad value collect2: error: ld returned 1 exit status make[2]: *** [lib/libopencv_videoio.so.3.0.0] Error 1 make[1]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/all] Error 2 make: *** [all] Error 2 I noticed a few posts mentioning similar errors and some solutions suggest removing the libavcodec.a from /usr/local/lib/. I'd like not to do that as I need ffmpeg libraries in the machine as well. Could someone please help me to resolve this issue?. Thanks c++  opencv  ubuntu share improve this question edited  Mar 10 '15 at 10:29 slhck 13.2k 16 73 122 asked  Mar 10 '15 at 10:12 userDtrm 60 8

Did you try the suggestion in the error message 'recompile with -fPIC' ? –  Ha Dang  Mar 10 '15 at 10:15 Yes. I tried editing the cmake list file by adding set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC" ). But that didn't work. I also tried to recompile ffmpeg with --enable-shared. But that didn't work as well. –  userDtrm  Mar 10 '15 at 11:48 Did you try to remove the libavcodec.a from the folder /usr/local/lib then rerun the compilation? You can move libavcodec.a to somewhere else then put it back to /usr/local/lib once you've done with opencv compilation. –  Ha Dang  Mar 10 '15 at 12:08 I had to remove libavformat.a libavutil.a libavcodec.a libswscale.a from /usr/local/lib and then compile opencv. Then the removed files were copied back to the location. It seems to have worked. Thanks a lot for the help. –  userDtrm  Mar 10 '15 at 18:14  Glad that it works. Have fun OpenCV-ing! :-) –  Ha Dang  Mar 10 '15 at 21:36