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。
- 设置包名等信息,点Finish完成
- 将编译好的FFMPEG下include目录拷贝到cpp目录下
- 增加abiFilters配置,指定ABI类型
externalNativeBuild {
cmake {
cppFlags "-std=c++11"
abiFilters 'armeabi-v7a'
}
}
- 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
- 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})
- 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
- 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
- 配置build.gradle
android {
defaultConfig {
//修改
externalNativeBuild {
ndk {
abiFilters 'armeabi-v7a'
}
}
}
externalNativeBuild {
//修改
ndkBuild {
path "src/main/cpp/Android.mk"
}
}
}