我按照https://juejin.cn/post/6844904062585045005配置了，编译就是报错：undefined reference to 'av_codec_next'。我的AS版本4.1.1，NDK版本22，ffmpeg版本4.3。build_android_clang.sh的API=29。看了源码说被丢弃了，好像也不是那么回事，调用其它函数也是这样，明明已经引入头文件了，点击也可以导航过去。
贴一下我的配置：
build.gradle：
plugins {
id 'com.android.application'
}
android {
compileSdkVersion 29
buildToolsVersion "30.0.2"
defaultConfig {
applicationId "com.example.ffmpegdemo"
minSdkVersion 23
targetSdkVersion 29
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
externalNativeBuild {
cmake {
cppFlags ""
}
ndk {
abiFilters "armeabi-v7a"
}
}
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
externalNativeBuild {
cmake {
path "src/main/cpp/CMakeLists.txt"
version "3.10.2"
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
}
dependencies {
implementation 'androidx.appcompat:appcompat:1.1.0'
implementation 'com.google.android.material:material:1.1.0'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
testImplementation 'junit:junit:4.+'
androidTestImplementation 'androidx.test.ext:junit:1.1.1'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
}
cmakelists：
# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html
# Sets the minimum version of CMake required to build the native library.
cmake_minimum_required(VERSION 3.10.2)
# 支持gnu++11
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")
# 1. 定义so库和头文件所在目录，方面后面使用
set(ffmpeg_lib_dir ${CMAKE_SOURCE_DIR}/../jniLibs/${ANDROID_ABI})
set(ffmpeg_head_dir ${CMAKE_SOURCE_DIR}/ffmpeg)
# 2. 添加头文件目录
include_directories(${ffmpeg_head_dir}/include)
#add ffmpeg
add_library( avutil
SHARED
IMPORTED )
set_target_properties( avutil
PROPERTIES IMPORTED_LOCATION
${ffmpeg_lib_dir}/libavutil.so )
add_library( swresample
SHARED
IMPORTED )
set_target_properties( swresample
PROPERTIES IMPORTED_LOCATION
${ffmpeg_lib_dir}/libswresample.so )
add_library( avcodec
SHARED
IMPORTED )
set_target_properties( avcodec
PROPERTIES IMPORTED_LOCATION
${ffmpeg_lib_dir}/libavcodec.so )
add_library( avfilter
SHARED
IMPORTED)
set_target_properties( avfilter
PROPERTIES IMPORTED_LOCATION
${ffmpeg_lib_dir}/libavfilter.so )
add_library( swscale
SHARED
IMPORTED)
set_target_properties( swscale
PROPERTIES IMPORTED_LOCATION
${ffmpeg_lib_dir}/libswscale.so )
add_library( avformat
SHARED
IMPORTED)
set_target_properties( avformat
PROPERTIES IMPORTED_LOCATION
${ffmpeg_lib_dir}/libavformat.so )
add_library( avdevice
SHARED
IMPORTED)
set_target_properties( avdevice
PROPERTIES IMPORTED_LOCATION
${ffmpeg_lib_dir}/libavdevice.so )
#add end
# Declares and names the project.
project("ffmpegdemo")
# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.
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).
native-lib.cpp )
# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.
find_library( # Sets the name of the path variable.
# log-lib
# 4. 连接 FFmpeg 相关的库
avutil
swresample
avcodec
avfilter
swscale
avformat
avdevice
# Specifies the name of the NDK library that
# you want CMake to locate.
# log
)
# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.
target_link_libraries( # Specifies the target library.
native-lib
# Links the target library to the log library
# included in the NDK.
# ${log-lib}
)
cpp文件：
#include <jni.h>
#include <string>
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavfilter/avfilter.h>
#include <libavcodec/jni.h>
JNIEXPORT jstring JNICALL
Java_com_example_ffmpegdemo_MainActivity_stringFromJNI(JNIEnv* env, jobject /* this */) {
std::string hello = "Hello from C++";
return env->NewStringUTF(hello.c_str());
}
JNIEXPORT jstring JNICALL
Java_com_example_ffmpegdemo_MainActivity_ffmpegInfo(JNIEnv *env, jobject thiz) {
// char info[40000] = {0};
// AVCodec *c_temp = av_codec_next(nullptr);
// while (c_temp != nullptr) {
// if (c_temp->decode != nullptr) {
// sprintf(info, "%sdecode:", info);
// } else {
// sprintf(info, "%sencode:", info);
// }
// switch (c_temp->type) {
// case AVMEDIA_TYPE_VIDEO:
// sprintf(info, "%s(video):", info);
// break;
// case AVMEDIA_TYPE_AUDIO:
// sprintf(info, "%s(audio):", info);
// break;
// default:
// sprintf(info, "%s(other):", info);
// break;
// }
// sprintf(info, "%s[%s]\n", info, c_temp->name);
// c_temp = c_temp->next;
// }
//
// return env->NewStringUTF(info);
avcodec_version();
}
}
