Android Studio2.2.3 通过JNI引用ffmpeg库小结

修改步骤：

1. 首先通过NDK14编译出libffmpeg.so ,将include目录取出

2. 通过AS建立基于jni的工程项目，将include目录放到cpp下；创建jniLibs/armeabi目录，将libffmpeg.so放到里边

    

3.配置CMakeLists.txt

添加如下：

#add the ffmpeg lib
include_directories(${CMAKE_CURRENT_SOURCE_DIR}/src/main/cpp/include)
add_library(ffmpeg-lib  SHARED IMPORTED )
set_target_properties(ffmpeg-lib PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/src/main/jniLibs/armeabi/libffmpeg.so)

target_link_libraries( native-lib
                       ffmpeg-lib             #ffmpeg lib
                       android                #use the android log lib
                       ${log-lib} )

4.配置build.gradle

    主要添加arguments 和 ndk的配置

externalNativeBuild {
    cmake {
        cppFlags " "
        arguments '-DANDROID_TOOLCHAIN=clang','-DANDROID_STL=gnustl_static'
    }

    ndk {
        abiFilters  'armeabi'
    }
}

5.native_lib.cpp

#include <jni.h>
#include <string>
#include <android/log.h>

extern "C"
{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include "libavutil/imgutils.h"
#include "libavutil/avutil.h"

}

#define  LOG_TAG    "MyTagFFmpeg"
#define  ALOGE(...)  __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__)

extern "C"
jstring
Java_letv_com_myffmpeg_MainActivityFFmpeg_stringFromJNI(
       JNIEnv *env,
       jobject /* this */) {
   std::string hello = "Hello ,this is the first ffmpeg test !";

   ALOGE("%s",hello.c_str());
   char info[10000] = { 0 };
   sprintf(info, "%s\n", avcodec_configuration());
   hello += info;

   return env->NewStringUTF(hello.c_str());
}

That's all.