android studio cmake FFmpeg

首先，前提是将FFmpeg编译生成库，具体的FFmpeg编译暂不做分享(涉及libfdk_aac,x264文章待续......)。
Android Studio2.2已经可以通过cmake建立JNI项目，而且native debug也很方便，于是通过cmake移植FFmpeg至android平台。

• 新建android项目，在src/main/目录下，创建JniLibs目录。并将动态库添加到此目录下，同时将FFMpeg编译生成的include头文件拷贝到cpp目录下.

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• JNI头文件生成
  编写native方法，alt+enter 生成头文件,实现简单调用

  
  
  

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• 在JNI中涉及一以C与C++的混合调用，不要忘记添加extern "C"{},否则编译会报错

  
  
  

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• 因为只编译armeabi-v7a平台的动态库，在CMakelists.txt文件中，通过配置文件添加依赖库，注意build.gradle中不要忘记添加ndk配置，否则会链接失败。

  
  
  

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• 以下为CMakelists.txt文件中的详细配置

set(include-headers ${CMAKE_SOURCE_DIR}/src/main/cpp/include)       //定义变量，设置头文件路径
include_directories(${include-headers})//引用变量包含头文件,否则编译过程中找不到头文件

add_library(avcodec SHARED IMPORTED)//添加动态库
set_target_properties(avcodec PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/src/main/jniLibs/armeabi-v7a/libavcodec-57.so)//动态库的路径

add_library(avdevice SHARED IMPORTED)
set_target_properties( avdevice
                       PROPERTIES
                       IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/src/main/jniLibs/armeabi-v7a/libavdevice-57.so )

 add_library(avfilter SHARED IMPORTED)
 set_target_properties( avfilter
                        PROPERTIES
                        IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/src/main/jniLibs/armeabi-v7a/libavfilter-6.so )

 add_library(avformat SHARED IMPORTED)
 set_target_properties( avformat
                        PROPERTIES
                        IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/src/main/jniLibs/armeabi-v7a/libavformat-57.so )

 add_library(avutil SHARED IMPORTED)
 set_target_properties( avutil
                        PROPERTIES
                        IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/src/main/jniLibs/armeabi-v7a/libavutil-55.so )

 add_library(postproc SHARED IMPORTED)
 set_target_properties( postproc
                        PROPERTIES
                        IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/src/main/jniLibs/armeabi-v7a/libpostproc-54.so )

 add_library(swresample SHARED IMPORTED)
 set_target_properties( swresample
                        PROPERTIES
                        IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/src/main/jniLibs/armeabi-v7a/libswresample-2.so )

 add_library(swscale SHARED IMPORTED)
 set_target_properties( swscale
                        PROPERTIES
                        IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/src/main/jniLibs/armeabi-v7a/libswscale-4.so )

add_library( # Sets the name of the library.
             native-lib
             # Sets the library as a shared library.
             SHARED
             # Provides a relative path to your source file(s).
             # Associated headers in the same location as their source
             # file are automatically included.
             src/main/cpp/native-lib.cpp )//通过源文件的形式，加入动态库

#以上添加依赖的动态库和源文件
#链接动态库
target_link_libraries( # Specifies the target library.
                       native-lib

                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib}
                        avcodec
                        avdevice
                        avfilter
                        avformat
                        avutil
                        postproc
                        swresample
                        swscale
                        )

ok，跑起......

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