FFmpeg在Ubuntu下的编译
VMware Workstation10
Ubuntu 16
android-ndk-r15c(用其他版本有时候编译不过)
ffmpeg-4.2.1（地址：https://www.johnvansickle.com/ffmpeg/）
将下载下来的ffmpeg进行解压
进入已解压的ffmpeg文件目录，修改configure文件；
SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_VERSION)'
SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'
修改为：
SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB)"$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
SLIB_INSTALL_LINKS='$(SLIBNAME)'
编写build_android.sh的可执行文件，并给权限 chmod 0777 build_android.sh
#!/bin/bash
# 清空上次的编译
make clean
#你自己的NDK路径.
export NDK=/home/huangsuwen/tangshanqiang/ffmpeg/android-ndk-r15c
function build_android
{
echo "Compiling FFmpeg for $CPU"
./configure \
--prefix=$PREFIX \
--enable-neon \
--enable-hwaccels \
--enable-gpl \
--enable-postproc \
--enable-shared \
--enable-jni \
--enable-mediacodec \
--enable-decoder=h264_mediacodec \
--disable-static \
--disable-doc \
--enable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--enable-avdevice \
--disable-doc \
--disable-symver \
--cross-prefix=$CROSS_PREFIX \
--target-os=android \
--arch=$ARCH \
--cpu=$CPU \
--enable-cross-compile \
--sysroot=$SYSROOT \
--extra-cflags="-Os -fpic $OPTIMIZE_CFLAGS" \
--extra-ldflags="$ADDI_LDFLAGS" \
$ADDITIONAL_CONFIGURE_FLAG
make clean
make
make install
echo "The Compilation of FFmpeg for $CPU is completed"
}
#armv8-a
if false;then
ARCH=arm64
CPU=armv8-a
TOOLCHAIN=$NDK/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64
SYSROOT=$NDK/platforms/android-21/arch-$ARCH/
CROSS_PREFIX=$TOOLCHAIN/bin/aarch64-linux-android-
PREFIX=$(pwd)/android/$CPU
OPTIMIZE_CFLAGS="-march=$CPU"
build_android
fi
#armv7-a
ARCH=arm
CPU=armv7-a
TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64
SYSROOT=$NDK/platforms/android-21/arch-$ARCH/
CROSS_PREFIX=$TOOLCHAIN/bin/arm-linux-androideabi-
PREFIX=$(pwd)/android/$CPU
rm -rf $PREFIX
mkdir -p $PREFIX
OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU "
build_android
if false;then
#x86
ARCH=x86
CPU=x86
TOOLCHAIN=$NDK/toolchains/x86-4.9/prebuilt/linux-x86_64
SYSROOT=$NDK/platforms/android-21/arch-$ARCH/
CROSS_PREFIX=$TOOLCHAIN/bin/i686-linux-android-
PREFIX=$(pwd)/android/$CPU
OPTIMIZE_CFLAGS="-march=i686 -mtune=intel -mssse3 -mfpmath=sse -m32"
build_android
fi
#x86_64
if false;then
ARCH=x86_64
CPU=x86-64
TOOLCHAIN=$NDK/toolchains/x86_64-4.9/prebuilt/linux-x86_64
SYSROOT=$NDK/platforms/android-21/arch-$ARCH/
CROSS_PREFIX=$TOOLCHAIN/bin/x86_64-linux-android-
PREFIX=$(pwd)/android/$CPU
OPTIMIZE_CFLAGS="-march=$CPU -msse4.2 -mpopcnt -m64 -mtune=intel"
build_android
fi;
安装必要的编译库；
sudo apt-get install make
sudo apt-get install gcc
执行FFmpeg源码的配置命./configure（build_android.sh执行前）
执行该句命令，如果报错：nasm/yasm not found or too old.则需要安装yasm，可以执行命令
sudo apt-get install yasm，或者按照提示执行./configure --disable-x86asm
安装完成好，再次执行FFmpeg源码的配置命令，yasm的错误信息已消除，但出现如下警告信息：
WARNING: pkg-config not found, library detection may fail.
执行安装命令sudo apt-get install pkg-config
再次执行FFmpeg源码的配置命令./configure
执行编译FFmpeg命令./build_android.sh;
如果出现/bin/bash^M: 解释器错误: 没有那个文件或目录，可以使用命令行 bash build_android.sh
如果出现找不到文件等是由于拷贝的文件是doc，查看 vim build_android.sh 进入：set ff 查看文件格式 fileformat=dos
安装工具：sudo apt-get install dos2unix
使用工具：dos2unix build_android.sh
查看格式： set ff
执行完编译./build_android.sh后，静等编译完成
编译生成静态库：
将ffbuild/library.mak中
install-lib$(NAME)-shared: $(SUBDIR)$(SLIBNAME)
$(Q)mkdir -p"$(SHLIBDIR)"
$$(INSTALL) -m 755 $$<"$(SHLIBDIR)/$(SLIB_INSTALL_NAME)"
$$(STRIP)"$(SHLIBDIR)/$(SLIB_INSTALL_NAME)"
$(Q)$(foreach F,$(SLIB_INSTALL_LINKS),(cd"$(SHLIBDIR)"&& $(LN_S) $(SLIB_INSTALL_NAME) $(F));)
$(if$(SLIB_INSTALL_EXTRA_SHLIB),$$(INSTALL) -m 644 $(SLIB_INSTALL_EXTRA_SHLIB:%=$(SUBDIR)%)"$(SHLIBDIR)")
$(if$(SLIB_INSTALL_EXTRA_LIB),$(Q)mkdir -p"$(LIBDIR)")
$(if$(SLIB_INSTALL_EXTRA_LIB),$$(INSTALL) -m 644 $(SLIB_INSTALL_EXTRA_LIB:%=$(SUBDIR)%)"$(LIBDIR)")
注释掉几行，如下：
install-lib$(NAME)-shared: $(SUBDIR)$(SLIBNAME)
$(Q)mkdir -p"$(SHLIBDIR)"
$$(INSTALL) -m 755 $$<"$(SHLIBDIR)/$(SLIB_INSTALL_NAME)"
# $$(STRIP) "$(SHLIBDIR)/$(SLIB_INSTALL_NAME)"
# $(Q)$(foreach F,$(SLIB_INSTALL_LINKS),(cd "$(SHLIBDIR)" && $(LN_S) $(SLIB_INSTALL_NAME) $(F));)
# $(if $(SLIB_INSTALL_EXTRA_SHLIB),$$(INSTALL) -m 644 $(SLIB_INSTALL_EXTRA_SHLIB:%=$(SUBDIR)%) "$(SHLIBDIR)")
# $(if $(SLIB_INSTALL_EXTRA_LIB),$(Q)mkdir -p "$(LIBDIR)")
# $(if $(SLIB_INSTALL_EXTRA_LIB),$$(INSTALL) -m 644 $(SLIB_INSTALL_EXTRA_LIB:%=$(SUBDIR)%) "$(LIBDIR)")
make，make install就能得到可直接使用的动态库，而非链接文件：的 libavcodec.so libavdevice.so libavfilter.so libavformat.so libavutil.so libswresample.so libswscale.so
以上方法很多编译不过，参照网上最新的做法：https://juejin.im/post/6844903945496690696?utm_source=gold_browser_extension
