Android工程中使用FFMPEG静态库(CMake和Android mk)

前言：
前文Mac下编译FFMPEG for Android中介绍了如何编译FFMPEG静态库。本文将介绍CMake和Android mk两种方式使用静态库。

主要内容

• CMake
• Android mk

CMake

CMake方式构建使用比较简单，创建的一个新的支持Native C++的工程默认使用此方式。

1. 设置包名等信息，点Finish完成
   
2. 将编译好的FFMPEG下include目录拷贝到cpp目录下
3. 增加abiFilters配置，指定ABI类型

externalNativeBuild {
    cmake {
        cppFlags "-std=c++11"
        abiFilters 'armeabi-v7a'
    }
}

4. cpp目录下创建armeabi-v7a文件夹，并拷贝编译好的静态库到该目录下
5. 修改CMakeLists.txt，增加如下配置

cmake_minimum_required(VERSION 3.4.1)

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)
//增加本地c文件目录
include_directories(include)
//设置静态库目录，这里abiFilters = armeabi-v7a
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -L${CMAKE_SOURCE_DIR}/${CMAKE_ANDROID_ARCH_ABI}")

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)

target_link_libraries( # Specifies the target library.
        native-lib
        //增加静态库
        avformat avcodec avfilter avutil swresample swscale
        # Links the target library to the log library
        # included in the NDK.
        ${log-lib})

6. 修改native-lib.cpp

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

extern "C" JNIEXPORT jstring JNICALL
Java_com_android_app_luping_MainActivity_stringFromJNI(
        JNIEnv *env,
        jobject /* this */) {
    return env->NewStringUTF(av_version_info());
}

Android mk

通过以上步骤生成工程后，要使用Android mk方式主要改动一下几个地方

1. 在cpp目录下创建Android.mk和Application.mk

#Android.mk
LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)
LOCAL_MODULE := avformat
LOCAL_SRC_FILES := ${TARGET_ARCH_ABI}/libavformat.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := avcodec
LOCAL_SRC_FILES := ${TARGET_ARCH_ABI}/libavcodec.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := avfilter
LOCAL_SRC_FILES := ${TARGET_ARCH_ABI}/libavfilter.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := avutil
LOCAL_SRC_FILES := ${TARGET_ARCH_ABI}/libavutil.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := swresample
LOCAL_SRC_FILES := ${TARGET_ARCH_ABI}/libswresample.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := swscale
LOCAL_SRC_FILES := ${TARGET_ARCH_ABI}/libswscale.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE    := native-lib
LOCAL_SRC_FILES := \
                native-lib.cpp
LOCAL_C_INCLUDES :=$(LOCAL_PATH)/include
LOCAL_STATIC_LIBRARIES := avformat avcodec avfilter avutil swresample swscale
LOCAL_CPPFLAGS:=-std=c++11
LOCAL_LDLIBS += -llog

include $(BUILD_SHARED_LIBRARY)

#Application.mk
APP_ABI := armeabi-v7a
APP_STL := c++_static

2. 配置build.gradle

android {
    defaultConfig {
    	//修改
        externalNativeBuild {
            ndk {
                abiFilters 'armeabi-v7a'
            }
        }
    }
    externalNativeBuild {
    	//修改
        ndkBuild {
            path "src/main/cpp/Android.mk"
        }
    }
}

结果

源码

https://github.com/panliangxiao/LuPingProject