android studio集成FFmpeg 爆 libavfilter.so', needed by 问题

Question

第一次，使用FFmpeg框架，我先在deepin上面编译其源码，得到了，include和so文件。然后复制到win10上面，并且建立项目如图：

然后我在CMarkLists.txt中添加了如下代码：

# 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.
include_directories(libs/include)
set(DIR ../../../../libs)
cmake_minimum_required(VERSION 3.4.1)

# 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).
             src/main/cpp/native-lib.cpp )


add_library(avcodec SHARED IMPORTED)
set_target_properties(avcodec PROPERTIES IMPORTED_LOCATION ${DIR}/armeabi-v7a/libavcodec.so)

add_library(avformat SHARED IMPORTED)
set_target_properties(avformat PROPERTIES IMPORTED_LOCATION ${DIR}/armeabi-v7a/libavformat.so)

add_library(avutil SHARED IMPORTED)
set_target_properties(avutil PROPERTIES IMPORTED_LOCATION ${DIR}/armeabi-v7a/libavutil.so)

add_library(swresample SHARED IMPORTED)
set_target_properties(swresample PROPERTIES IMPORTED_LOCATION ${DIR}/armeabi-v7a/libswresample.so)

add_library(swscale SHARED IMPORTED)
set_target_properties(swscale PROPERTIES IMPORTED_LOCATION ${DIR}/armeabi-v7a/libswscale.so)

add_library(avfilter SHARED IMPORTED)
set_target_properties(avfilter PROPERTIES IMPORTED_LOCATION ${DIR}/armeabi-v7a/libavfilter.so)


# 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

              # 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
                       avfilter
                       avcodec
                       avformat
                       avutil
                       swresample
                       swscale
                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

在gradle.build中添加了如下代码：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "cn.lxw.ffmpeg"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"


        sourceSets{
            main{
                jniLibs.srcDirs = ['libs']
            }
        }

        externalNativeBuild {
            cmake {
                cppFlags ""
                abiFilters 'armeabi-v7a'
            }
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

然后在项目默认的一个cpp文件中，调用一下相关方法。
native-lib.cpp

#include <jni.h>
#include <string>
#include <libavcodec/avcodec.h>

extern "C" JNIEXPORT jstring JNICALL
Java_cn_lxw_ffmpeg_MainActivity_stringFromJNI(
        JNIEnv* env,
        jobject /* this */) {
    std::string hello = avcodec_configuration();
    return env->NewStringUTF(hello.c_str());
}

然后我尝试运行项目，却爆出以下错误：

Build native-lib armeabi-v7a
ninja: error: '../../../../libs/armeabi-v7a/libavfilter.so', needed by '../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libnative-lib.so', missing and no known rule to make it
:app:externalNativeBuildDebug FAILED
:app:buildInfoGeneratorDebug

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:externalNativeBuildDebug'.
> Build command failed.
  Error while executing process D:\Dev\sdk\cmake\3.6.4111459\bin\cmake.exe with arguments {--build D:\Dev\WorkSpace\FFmpeg\app\.externalNativeBuild\cmake\debug\armeabi-v7a --target native-lib}
  ninja: error: '../../../../libs/armeabi-v7a/libavfilter.so', needed by '../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libnative-lib.so', missing and no known rule to make it

请问怎么修复， 谢谢大家~！

Answer 1

你好，我也遇到了这个问题，请问你解决了吗