安卓工程集成ffmpeg

最近在学习ffmpeg框架，网上找了很多资料，对着操作但还是报了很多错误，摸索了很久也没有摸到窍门，但是今天终于成功了，下面把集成过程写一下，以免以后忘记了。

1.创建c++工程

2.添加库文件

将编译后的so文件加入libs文件夹中，将include文件夹加入cpp文件夹下
ffmpeg文件夹如图所示

添加so文件如下图展示

设置ndk：ndk选择r17c，一定要选择合适的ndk，要不然会报错

3.将so文件与工程结合

CMakeLists.txt展示，这里主要是绑定so文件

# 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)

# Declares and names the project.

project("ffmpeg_test3")


#include_directories(//libs/include)
set(DIR ../../../../libs)
include_directories(${CMAKE_SOURCE_DIR}/include)


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

add_library(avdevice
        SHARED
        IMPORTED)
set_target_properties(avdevice
        PROPERTIES IMPORTED_LOCATION
        ${DIR}/armeabi-v7a/libavdevice.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)




# 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

        # 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
        avdevice
        avformat
        avutil
        swresample
        swscale

        # Links the target library to the log library
        # included in the NDK.
        ${log-lib} )

build.gradle文件展示 添加ndk

plugins {
    id 'com.android.application'
}

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.2"

    defaultConfig {
        applicationId "com.example.ffmpeg_test3"
        minSdkVersion 16
        targetSdkVersion 30
        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 fileTree(include: ['*.jar'], dir: 'libs')

    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'
}

**

4.使用测试

**
MainActivity文件

package com.example.ffmpeg_test3;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    // Used to load the 'native-lib' library on application startup.
    static {
        System.loadLibrary("native-lib");
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Example of a call to a native method
        TextView tv = findViewById(R.id.sample_text);
        tv.setText(stringFromJNI2());
    }

    /**
     * A native method that is implemented by the 'native-lib' native library,
     * which is packaged with this application.
     */
    public native String stringFromJNI2();
}

native-lib.cpp文件展示

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

extern "C" JNIEXPORT jstring JNICALL
Java_com_example_ffmpeg_1test3_MainActivity_stringFromJNI(
        JNIEnv* env,
        jobject /* this */) {
    std::string hello = "Hello from C++";
    return env->NewStringUTF(hello.c_str());
}

extern "C"{
#include <libavutil/avutil.h>
JNIEXPORT jstring JNICALL
Java_com_example_ffmpeg_1test3_MainActivity_stringFromJNI2(JNIEnv *env, jobject thiz) {
    // TODO: implement stringFromJNI()
    std::string hello = av_version_info();
    return env->NewStringUTF(hello.c_str());
}

}

结果显示