FFmpeg（四）：CMake移植FFmpeg的静态库到Andr

前言

本文将介绍如何把FFmpeg（二）：Windows下编译全平台架构的FFmpeg中编译出的支持全平台的FFmpeg静态so库，采用CMake方式移植到AndroidStudio中，并打印出FFmpeg的信息。

正文

• 1 相关文件拷贝

  • 1.1 添加FFmpeg编译出的静态库

    在 FFmpeg（二）：Windows下编译全平台架构的FFmpeg中我们将FFmpeg编译生成了各个平台适用的静态库，我们将每个CPU下的lib路径下的所有so包提取出来，在Android工程中的libs下建立各个平台对应的文件名称，并拷贝进去，如图所示：
    

    

  • 1.2 拷贝头文件

    将 FFmpeg（二）：Windows下编译全平台架构的FFmpeg中android_more下任意平台下的include文件夹全部拷贝至项目工程中src/main/cpp中，如图所示：

    

  • 1.3 拷贝H264头文件

    在项目工程src/main/cpp/include下新建文件夹libx264，并把FFmpeg-3.2.5/libx264/android/任意CPU/include下编译出的x264.h和x264_config.h拷贝进去

• 2 编写CMakeList.txt链接添加共享包

  看不懂第2步骤的请回头FFmpeg（三）：初识CMakeList和native-lib

  • 2.1 以CMakeList.txt为基准设置相对路径

    set(distribution_DIR ${CMAKE_SOURCE_DIR}/../../../../libs)
    

  • 2.2 加载头文件和设置源码路径

    include_directories(
            # 加载头文件
             src/main/cpp/include
            #源码路径为绝对路径，下载后请记得修改你的源码路径
             E:/Workspace/OtherDemo/FFmpeg4Android-master/ffmpeg-3.2.5  ) 
    

  • 2.3 add_library添加共享库

    我们把libavcodec.so、libavfilter.so、libavformat.so、libavutil.so、libfdk-aac.so、libswresample.so、libswscale.so这七个库导入添加到共享库（这里不关注CPU架构），IMPORTED指2.4中根据CPU架构导入指定的so库。

    add_library(
       avcodec
       SHARED
       IMPORTED   )
    add_library(
       avfilter
       SHARED
       IMPORTED  )
    add_library(
       avformat
       SHARED
       IMPORTED  )
    add_library(
       avutil
       SHARED
       IMPORTED  )
    add_library(
       swresample
       SHARED
       IMPORTED  )
    add_library(
       swscale
       SHARED
       IMPORTED  )
    add_library(
       fdk-aac
       SHARED
       IMPORTED  )
    

    • 2.4 设置目标版本库

    判断当前机型是哪个CPU架构，就加载libs下对应的so包：

     #判断目标版本并设置
     if(${ANDROID_ABI} STREQUAL "armeabi")
     set_target_properties(
       avcodec
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi/libavcodec.so
     )
     set_target_properties(
       avfilter
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi/libavfilter.so
     )
     set_target_properties(
       avformat
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi/libavformat.so
       )
    
     set_target_properties(
       avutil
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi/libavutil.so
       )
     set_target_properties(
       swresample
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi/libswresample.so
        )
     set_target_properties(
       swscale
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi/libswscale.so
        )
     set_target_properties(
       fdk-aac
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi/libfdk-aac.so
        )
     endif(${ANDROID_ABI} STREQUAL "armeabi")
    
     if(${ANDROID_ABI} STREQUAL "armeabi-v7a")
    
     set_target_properties(
       avcodec
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi-v7a/libavcodec.so
     )
    
     set_target_properties(
      avfilter
      PROPERTIES IMPORTED_LOCATION
      ../../../../libs/armeabi-v7a/libavfilter.so
      )
    
     set_target_properties(
       avformat
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi-v7a/libavformat.so
       )
    
     set_target_properties(
       avutil
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi-v7a/libavutil.so
       )
    
     set_target_properties(
       swresample
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi-v7a/libswresample.so
        )
    
     set_target_properties(
       swscale
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi-v7a/libswscale.so
        )
    
     set_target_properties(
       fdk-aac
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/armeabi-v7a/libfdk-aac.so
        )
     endif(${ANDROID_ABI} STREQUAL "armeabi-v7a")
    
     if(${ANDROID_ABI} STREQUAL "arm64-v8a")
     set_target_properties(
     avcodec
     PROPERTIES IMPORTED_LOCATION
     ../../../../libs/arm64-v8a/libavcodec.so
      )
    
     set_target_properties(
     avfilter
     PROPERTIES IMPORTED_LOCATION
     ../../../../libs/arm64-v8a/libavfilter.so
      )
    
     set_target_properties(
       avformat
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/arm64-v8a/libavformat.so
       )
    
     set_target_properties(
       avutil
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/arm64-v8a/libavutil.so
       )
    
     set_target_properties(
       swresample
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/arm64-v8a/libswresample.so
        )
    
     set_target_properties(
       swscale
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/arm64-v8a/libswscale.so
        )
    
    
     set_target_properties(
       fdk-aac
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/arm64-v8a/libfdk-aac.so
        )
     endif(${ANDROID_ABI} STREQUAL "arm64-v8a")
    
     if(${ANDROID_ABI} STREQUAL "x86")
     set_target_properties(
      avcodec
      PROPERTIES IMPORTED_LOCATION
      ../../../../libs/x86/libavcodec.so
     )
    
     set_target_properties(
       avfilter
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86/libavfilter.so
     )
    
     set_target_properties(
       avformat
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86/libavformat.so
       )
    
     set_target_properties(
       avutil
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86/libavutil.so
       )
    
     set_target_properties(
       swresample
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86/libswresample.so
        )
    
     set_target_properties(
       swscale
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86/libswscale.so
        )
    
     set_target_properties(
       fdk-aac
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86/libfdk-aac.so
        )
     endif(${ANDROID_ABI} STREQUAL "x86")
    
     if(${ANDROID_ABI} STREQUAL "x86_64")
     set_target_properties(
       avcodec
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86_64/libavcodec.so
     )
    
     set_target_properties(
      avfilter
      PROPERTIES IMPORTED_LOCATION
      ../../../../libs/x86_64/libavfilter.so
     )
    
     set_target_properties(
       avformat
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86_64/libavformat.so
       )
    
     set_target_properties(
       avutil
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86_64/libavutil.so
       )
    
     set_target_properties(
       swresample
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86_64/libswresample.so
        )
    
     set_target_properties(
       swscale
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86_64/libswscale.so
        )
    
     set_target_properties(
       fdk-aac
       PROPERTIES IMPORTED_LOCATION
       ../../../../libs/x86_64/libfdk-aac.so
        )
     endif(${ANDROID_ABI} STREQUAL "x86_64")
    

    • 2.5连接共享库

    将所有添加进来的共享库和NDK中查到到已有的库链接起来：

     target_link_libraries(
                  native-lib
                  fdk-aac
                  avcodec
                  avfilter
                  avformat
                  avutil
                  swresample
                  swscale
                  ${log-lib}  )      
    

• 3 相关代码编写

  • 3.1新建java文件FFmpegKit，内容如下：

  /**
   * Created by MouShao on 2018/2/28.
   */
  public class FFmpegKit {
  static {
    //加载CMakeList中连接的共享库
    System.loadLibrary("native-lib");
    System.loadLibrary("avutil");
    System.loadLibrary("fdk-aac");
    System.loadLibrary("avcodec");
    System.loadLibrary("avformat");
    System.loadLibrary("swscale");
    System.loadLibrary("swresample");
    System.loadLibrary("avfilter");
    }
    public static native String stringFromFFmpeg();
  }
  

• 3.2 native-lib.cpp编写

  #include <jni.h>
  #include <string>
  #include <android/log.h>
  
  extern "C" {
  #include "libavcodec/avcodec.h"
  #include "libavfilter/avfilter.h"
  #include "libavformat/avformat.h"
  #include "libavutil/imgutils.h"
  #include "libswresample/swresample.h"
  #include "libswscale/swscale.h"
  #include "libx264/x264.h"
  
  #define  LOG_TAG    "videoplayer"
  #define  LOGD(...)  __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__)
  
  JNIEXPORT jstring JNICALL Java_com_pvirtech_ffmpeg4android_FFmpegKit_stringFromFFmpeg(
    JNIEnv *env,
    jobject /* this */ obj) {
        char info[10000] = {0};
        sprintf(info, "%s\n", avcodec_configuration());
        return env->NewStringUTF(info);
     }
  };
  

• 3.3 app下build.gradle的配置

    android {
    ···
    defaultConfig {
    ···
    externalNativeBuild {
        cmake {
            //配置C++11标准
            cppFlags "-std=c++11"
        }
        ndk{
            //abi兼容设置
            abiFilters "armeabi-v7a","armeabi","arm64-v8a","x86","x86_64"
        }
    }
  }
      //导入app/libs下库
      sourceSets.main {
      jniLibs.srcDirs = ['libs']
      jni.srcDirs = []
    }
  }
  

• 3.4 MainActivity调用

• 4 运行如图所示：

结语

到此，FFmpeg的首秀就完成了，下一篇我们将如何用JNI动态注册的方式调用FFmpeg播放视频。

下一节讲：
FFmpeg（五）：JNI动态注册方法调用FFmpeg播放视频

github源码

简书半停更说明

碎碎念：如果诸君喜欢，请点个赞

更多问题，欢迎加群：584275290