opencv交叉编译环境搭建-aarch64
#背景
要将交叉编译应用到64位arm端(rockchip)运行，应用使用到opencv
#版本
PC虚拟机: ubuntu16.04
opencv: 3.4.4
交叉编译器: aarch64-linux-gnu 5.4.0
相关依赖：
zlib-1.2.11
jpegsrc.v9b
libpng-1.6.36
yasm-1.3.0
x264-snapshot
xvidcore_1.3.3.orig
ffmpeg-4.1
各个依赖库下载地址：
zlib官网：http://www.zlib.net/
libjpeg下载地址：http://www.ijg.org/files/
libpng下载地址：http://www.libpng.org/pub/png/libpng.html
yasm下载地址：http://yasm.tortall.net/Download.html
x264下载地址：http://www.videolan.org/developers/x264.html
或者：http://download.videolan.org/pub/videolan/x264/snapshots/
libxvid下载地址：http://ftp.br.debian.org/debian-multimedia/pool/main/x/xvidcore/
ffmpeg下载地址：http://ffmpeg.org/download.html
opencv下载地址：https://opencv.org/
当然，网页打开可能需要工具，如果不行，可从文末网盘下载。
#编译
编译zlib
export OPENCV_DEPEND=安装路径
sudo ./configure –prefix=$OPENCV_DEPEND
修改Makefile
CC=aarch64-linux-gnu-gcc
AR=aarch64-linux-gnu-ar
RANLIB=aarch64-linux-gnu-ranlib
LDSHARED=aarch64-linux-gnu-gcc -shared -Wl,-soname,libz.so.1,–version-script,zlib.map
make
make install
编译jpeg
sudo ./configure –host=aarch64-linux-gnu –prefix=$OPENCV_DEPEND –enable-shared –enable-static CC=aarch64-linux-gnu-gcc
make
make install
编译libpng
sudo ./configure –host=aarch64-linux-gnu –prefix=$OPENCV_DEPEND –enable-shared –enable-static CC=aarch64-linux-gnu-gcc
make
make install
编译yasm
sudo CC=aarch64-linux-gnu-gcc ./configure --enable-shared --host=aarch64-linux-gnu --disable-asm --prefix=$OPENCV_DEPEND
make
make install
编译libx264
export OPENCV_DEPEND=/home/rank/HaiSi/opencv-depend/
cd /home/rank/HaiSi/opencv/x264-snapshot-20170415-2245
sudo ./configure --prefix=$OPENCV_DEPEND --enable-shared --host=aarch64-linux-gnu --cross-prefix=aarch64-linux-gnu-
make
make install
编译libxvidcore
cd ./build/generic
sudo ./configure --prefix=$OPENCV_DEPEND --host=aarch64-linux-gnu --disable-assembly
make
make install
编译ffmpeg-2.8.11
sudo ./configure --prefix=$OPENCV_DEPEND --enable-shared --disable-static --enable-gpl --enable-cross-compile \
--arch=arm64 --disable-stripping --target-os=linux --enable-libx264 --enable-libxvid --cc=aarch64-linux-gnu-gcc \
--enable-swscale --extra-ldflags=-L$OPENCV_DEPEND/lib --extra-cflags=-I$OPENCV_DEPEND/include
make
make install
完成以后将opencv-depend/lib/* 复制到交叉编译工具链的lib目录
将opencv-depend/lib/* 复制到到交叉编译工具链的include目录
编译opencv-3.4.4
cd opencv-3.4.4
mkdir build
cmake-gui (未安装的话apt-get install cmake cmake-qt-gui)
设置源码地址和生成地址（为上面新建的build文件夹）
添加Cache Entry
Name=CMAKE_AR;
Type=FILEPATH
Value = /usr/bin/aarch64-linux-gnu-ar
点击configure,选择specify toolchain for cross-compiling
Next
Specify the Toolchain file选择opencv-3.4.4/platforms/linux/aarch64-gnu.toolchain.cmake
Finish
默认安装项，或自行增减。
当前项目需要用到libopencv_imgcodecs，所在必须是opencv3版本以上才有此项。
Configure
Generate
关掉cmake
进入build文件夹，
make
make install
随后可将build/insall下的库拷贝出来用了。
网盘中有相关源码和编译好的opencv
链接：https://pan.baidu.com/s/1kvYvun9TRCDgiZMiYgyqTg
提取码：lpb4
#参考：
https://blog.csdn.net/ajianyingxiaoqinghan/article/details/70194392
http://www.bubuko.com/infodetail-2561158.html
https://blog.csdn.net/rank_ck/article/details/82659343