Android Studio引入FFmpeg的方法

新建C++工程

新建

两个externalNativeBuild

一个sourceSets（指定so路径）

android {
 compileSdkVersion 29
 buildToolsVersion \"29.0.3\"
 defaultConfig {
 ...
 externalNativeBuild {
  cmake {
  cppFlags \"-std=c++11 -frtti -fexceptions\"
  abiFilters \'armeabi-v7a\'
  }
 }
 sourceSets {
  main {
  jniLibs.srcDirs = [\'src/main/jniLibs\']
  }
 }
 }
 ...
 externalNativeBuild {
 cmake {
  path \"src/main/cpp/CMakeLists.txt\"
  version \"3.10.2\"
 }
 }
}

复制so和include文件

编写CMakeLists.txt

以下是默认值

cmake_minimum_required(VERSION 3.4.1)

add_library(native-lib
 SHARED
 native-lib.cpp
 #nativ-lib2.cpp 如果有其他cpp文件可以一并打包到native-lib中)

#查找系统的log库，并赋值给变量log-lib
find_library(
 log-lib
 log)

#将上面log-lib变量里的库连接到native-lib中
target_link_libraries(
 native-lib
 ${log-lib})

CMakeLists中添加FFmpeg头文件路径

#设置FFmpeg头文件的路径
include_directories(
 include#因为和CMakeLists.txt在同一级，所以直接写include
)

CMakeLists中添加libavcodec.so

#定义一个变量avcodec
add_library(
 avcodec
 SHARED
 IMPORTED
)

#给avcodec这个变量赋值
set_target_properties(avcodec PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libavcodec.so)

#将avcodec混合编译到native-lib中
target_link_libraries(
 native-lib
 ${log-lib}
 avcodec
)

CMakeLists中添加全部的so

cmake_minimum_required(VERSION 3.4.1)

#设置FFmpeg头文件的路径
include_directories(
 include#因为和CMakeLists.txt在同一级，所以直接写include
)

add_library(native-lib
 SHARED
 native-lib.cpp)

find_library(
 log-lib
 log)

#1.定义一个变量avcodec
add_library(
 avcodec
 SHARED
 IMPORTED
)
#给avcodec这个变量赋值
set_target_properties(avcodec PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libavcodec-57.so)

#2.
add_library(
 avdevice
 SHARED
 IMPORTED
)
set_target_properties(avdevice PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libavdevice-57.so)

#3.
add_library(
 avfilter
 SHARED
 IMPORTED
)
set_target_properties(avfilter PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libavfilter-6.so)

#4.
add_library(
 avformat
 SHARED
 IMPORTED
)
set_target_properties(avformat PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libavformat-57.so)

#5.
add_library(
 avutil
 SHARED
 IMPORTED
)
set_target_properties(avutil PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libavutil-55.so)

#6.
add_library(
 postproc
 SHARED
 IMPORTED
)
set_target_properties(postproc PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libpostproc-54.so)

#7.
add_library(
 swresample
 SHARED
 IMPORTED
)
set_target_properties(swresample PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libswresample-2.so)

#8.
add_library(
 swscale
 SHARED
 IMPORTED
)
set_target_properties(swscale PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/../../main/jniLibs/${ANDROID_ABI}/libswscale-4.so)

#将avcodec混合编译到native-lib中
target_link_libraries(
 native-lib
 ${log-lib}
 avcodec#1
 avdevice#2
 avfilter#3
 avformat#4
 avutil#5
 postproc#6
 swresample#7
 swscale#8
)

编写测试函数

#include <jni.h>
#include <string>

extern \"C\" {
#include \"libavcodec/avcodec.h\"
}

extern \"C\" JNIEXPORT jstring JNICALL
Java_com_example_myffmpegcmd_MainActivity_stringFromJNI(
 JNIEnv *env,
 jobject /* this */) {
 std::string hello = \"Hello from C++\";
 return env->NewStringUTF(avcodec_configuration());
}