前言

编译FFmpeg的Android版本，并整合到Android Studio。
系统：macOS Sierra 10.12。
NDK版本：r12b。
FFmpeg版本：3.1.3

编译FFmpeg的步骤

• 下载NDK。

• 下载ffmpeg源码，解压到NDK目录下的sources目录下。如图

• 修改ffmpeg-3.1.3目录下的configure文件 定位到3309行：如图：

将

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)'
 

改成

SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)$(LIBMAJOR)$(SLIBSUF)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
SLIB_INSTALL_LINKS='$(SLIBNAME)'

目的是将生成.so名称规范化，用以满足android build。

• 在当前目录下新建一个build_android.sh文件，如图：

内容为：

#!/bin/bash
NDK=/Users/maimingliang/Documents/NDK/android-ndk-r12b
SYSROOT=$NDK/platforms/android-15/arch-arm/
TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64
function build_one
{
./configure \
 --prefix=$PREFIX \
 --enable-shared \
 --disable-static \
 --disable-doc \
 --disable-ffmpeg \
 --disable-ffplay \
 --disable-ffprobe \
 --disable-ffserver \
 --disable-avdevice \
 --disable-doc \
 --disable-symver \
 --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
 --target-os=linux \
 --arch=arm \
 --enable-cross-compile \
 --sysroot=$SYSROOT \
 --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
 --extra-ldflags="$ADDI_LDFLAGS" \
 $ADDITIONAL_CONFIGURE_FLAG
make clean
make
make install
}
CPU=arm
PREFIX=$(pwd)/android/$CPU 
ADDI_CFLAGS="-marm"
build_one

• 打开终端并且把路径切换到build_android 所在的目录 ，执行命令

./build_android.sh

完成编译以后，进入生成的android文件夹，在arm文件夹里面新建一个Android.mk文件，内容为：

LOCAL_PATH:= $(call my-dir)
 
include $(CLEAR_VARS)
LOCAL_MODULE:= libavcodec
LOCAL_SRC_FILES:= lib/libavcodec-57.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
include $(PREBUILT_SHARED_LIBRARY)
 
include $(CLEAR_VARS)
LOCAL_MODULE:= libavformat
LOCAL_SRC_FILES:= lib/libavformat-57.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
include $(PREBUILT_SHARED_LIBRARY)
 
include $(CLEAR_VARS)
LOCAL_MODULE:= libswscale
LOCAL_SRC_FILES:= lib/libswscale-4.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
include $(PREBUILT_SHARED_LIBRARY)
 
include $(CLEAR_VARS)
LOCAL_MODULE:= libavutil
LOCAL_SRC_FILES:= lib/libavutil-55.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
include $(PREBUILT_SHARED_LIBRARY)
 
include $(CLEAR_VARS)
LOCAL_MODULE:= libavfilter
LOCAL_SRC_FILES:= lib/libavfilter-6.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
include $(PREBUILT_SHARED_LIBRARY)
 
include $(CLEAR_VARS)
LOCAL_MODULE:= libswresample
LOCAL_SRC_FILES:= lib/libswresample-2.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
include $(PREBUILT_SHARED_LIBRARY)

至此FFmpeg的编译完成，下面整合到Android Studio 中：

配置Android Studio

• 在local.properties加入ndk的路径，我这里是：

ndk.dir=/Users/maimingliang/Documents/NDK/android-ndk-r12b

也可以在project structure 中添加。如图所示：

• 在build.gradle 文件中添加图中标红处的内容。

• 配置javah，ndk-build ，ndk-build clean 命令

添加javah命令:

program：$JDKPath$/bin/javah
paramers：-classpath $Classpath$ -v -jni $FileClass$
working diretory : $ModuleFileDir$/src/main/jni

添加 ndk-build

program：/Users/maimingliang/Documents/NDK/android-ndk-r12b/build/ndk-build //这里要修改你的ndk路径 的ndk-build
paramers：
working diretory : $ModuleFileDir$/src/main/jni

添加 ndk-build clean

program：/Users/maimingliang/Documents/NDK/android-ndk-r12b/build/ndk-build //这里要修改你的ndk路径的 ndk-build
paramers：clean
working diretory : $ProjectFileDir$/app/src/main

• 编写 C文件
• 编写Android.mk文件
• 编写Application.mk文件。
• 运行 javah，ndk-build ndk-build clean 命令

END.