环境
ndk个版本下载地址选择:https://blog.csdn.net/shuzfan/article/details/52690554
2.配置环境变量并为ndk授权
//进入当前用户根目录
cd ~
//编辑
vim ~/.bashrc
//编辑 ndk为例
export NDKROOT=/usr/ndk/android-ndk-r13b
export PATH=$NDKROOT:$PATH
//更新环境变量
source ~/.bashrc
//授权
chmod 777 -R /usr/ndk
3.下载ffmpge,解压授权
//下载
wget http://ffmpeg.org/releases/ffmpeg-3.0.11.tar.gz
//解压
tar zxvf ffmpeg-3.0.11.tar.gz
//授权
chmod 777 -R /usr/zzw/ffmpeg-3.0.11
ffmpeg各版本下载地址:http://ffmpeg.org/download.html
注意”\“后面不要放空格
4.2 使用xftp传输到云主机的ffmpeg解压根目录,并将该文件改为linux的编码
vim build_android.sh
#vim下执行
:set ff=unix
:wq
4.3 修改configure
#这段脚本的作用是使生成的静态库为.so为后缀,生成的库是这种格式:libavcodec-57.so ...
#不加的话生成的库是这种格式:libavcodec.so.57 ...等等
#注释以下内容
#SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'
#LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
#SLIB_INSTALL_NAME='$(SLIBNAME_WITH_VERSION)'
#SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'
#增加以下内容
SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB)"$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
SLIB_INSTALL_LINKS='$(SLIBNAME)'
6.上面生成的是so动态库,生成.a静态库只需在build_android.sh修改如下:
--enable-static \
--disable-shared \
7.生成一个库,在第6步生成静态库.a文件下,在build_android.sh的函数build_one添加如下:
#!/bin/bash
export TMPDIR=/usr/zzw/ffmpeg-3.0.11/ffmpegtemp
NDK=/usr/ndk/android-ndk-r13b
PLATFORM=$NDK/platforms/android-14/arch-arm/
TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64
function build_one
{
./configure \
--prefix=$PREFIX \
--target-os=linux \
--cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
--arch=arm \
--sysroot=$PLATFORM \
--extra-cflags="-I$PLATFORM/usr/include" \
--cc=$TOOLCHAIN/bin/arm-linux-androideabi-gcc \
--nm=$TOOLCHAIN/bin/arm-linux-androideabi-nm \
--enable-static \
--enable-runtime-cpudetect \
--enable-gpl \
--enable-small \
--enable-cross-compile \
--disable-debug \
--disable-shared \
--disable-doc \
--disable-asm \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-ffserver \
--disable-postproc \
--disable-avdevice \
--disable-symver \
--disable-stripping \
$ADDITIONAL_CONFIGURE_FLAG
sed -i '' 's/HAVE_LRINT 0/HAVE_LRINT 1/g' config.h
sed -i '' 's/HAVE_LRINTF 0/HAVE_LRINTF 1/g' config.h
sed -i '' 's/HAVE_ROUND 0/HAVE_ROUND 1/g' config.h
sed -i '' 's/HAVE_ROUNDF 0/HAVE_ROUNDF 1/g' config.h
sed -i '' 's/HAVE_TRUNC 0/HAVE_TRUNC 1/g' config.h
sed -i '' 's/HAVE_TRUNCF 0/HAVE_TRUNCF 1/g' config.h
sed -i '' 's/HAVE_CBRT 0/HAVE_CBRT 1/g' config.h
sed -i '' 's/HAVE_RINT 0/HAVE_RINT 1/g' config.h
make clean
make -j4
make install
# 增加的内容
$TOOLCHAIN/bin/arm-linux-androideabi-ld \
-rpath-link=$PLATFORM/usr/lib \
-L$PLATFORM/usr/lib \
-L$PREFIX/lib \
-soname libffmpeg.so -shared -nostdlib -Bsymbolic --whole-archive --no-undefined -o \
$PREFIX/libffmpeg.so \
libavcodec/libavcodec.a \
libavfilter/libavfilter.a \
libswresample/libswresample.a \
libavformat/libavformat.a \
libavutil/libavutil.a \
libswscale/libswscale.a \
-lc -lm -lz -ldl -llog --dynamic-linker=/system/bin/linker \
$TOOLCHAIN/lib/gcc/arm-linux-androideabi/4.9.x/libgcc.a \
}
# arm v7vfp
CPU=armv7-a
OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU "
PREFIX=./android/$CPU-vfp
ADDITIONAL_CONFIGURE_FLAG=
build_one
# CPU=armv
# PREFIX=$(pwd)/android/$CPU
# ADDI_CFLAGS="-marm"
# build_one
#arm v6
#CPU=armv6
#OPTIMIZE_CFLAGS="-marm -march=$CPU"
#PREFIX=./android/$CPU
#ADDITIONAL_CONFIGURE_FLAG=
#build_one
#arm v7vfpv3
# CPU=armv7-a
# OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=$CPU "
# PREFIX=./android/$CPU
# ADDITIONAL_CONFIGURE_FLAG=
# build_one
#arm v7n
#CPU=armv7-a
#OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -march=$CPU -mtune=cortex-a8"
#PREFIX=./android/$CPU
#ADDITIONAL_CONFIGURE_FLAG=--enable-neon
#build_one
#arm v6+vfp
#CPU=armv6
#OPTIMIZE_CFLAGS="-DCMP_HAVE_VFP -mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU"
#PREFIX=./android/${CPU}_vfp
#ADDITIONAL_CONFIGURE_FLAG=
#build_one
8.具体要编译哪个库,自己设置。 通过
./configure --help
命令查看怎么设置,通过打开configure文件查看所对应的库之间的依赖等。
依赖关系
# libraries, in linking order
avcodec_deps="avutil"
avcodec_select="null_bsf"
avdevice_deps="avformat avcodec avutil"
avfilter_deps="avutil"
avformat_deps="avcodec avutil"
avformat_suggest="network"
avresample_deps="avutil"
postproc_deps="avutil gpl"
swresample_deps="avutil"
swscale_deps="avutil"
通过这个就可以知道在android里面的so库加载顺序
static {
System.loadLibrary("avutil-55");
System.loadLibrary("swresample-2");
System.loadLibrary("avcodec-57");
System.loadLibrary("avformat-57");
System.loadLibrary("swscale-4");
System.loadLibrary("avfilter-6");
//自己实现逻辑编译的库
System.loadLibrary("native-lib");
}
也可以通过查看生成的lib/pkgconfig里面对应的pc文件查看具体的依赖关系
比如libavfilter.pc
prefix=./android/armv7-a-vfp
exec_prefix=${prefix}
libdir=${prefix}/lib
includedir=${prefix}/include
Name: libavfilter
Description: FFmpeg audio/video filtering library
Version: 6.31.100
Requires:
Requires.private: libswscale >= 4.0.100, libavformat >= 57.25.100, libavcodec >= 57.24.102, libswresample >= 2.0.101, libavutil >= 55.17.103
Conflicts:
Libs: -L${libdir} -lavfilter
Libs.private: -lm -lz -pthread
Cflags: -I${includedir}