Android Studio引入FFmpeg的方法

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"
 }
 }
}

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})

#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
)

#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
)

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
)

#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());
}