Android-FFMPEG(v4.3) MacOSX下使用ND

1. FFMPEG根目录下，编译脚本如下：

#!/bin/bash

# ndk路径
NDK=/Users/XXXX/Library/Android/sdk/ndk/21.1.6352462
# 编译工具链目录，ndk17版本以上用的是clang，以下是gcc
TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/darwin-x86_64
# 版本号
API=21
# 交叉编译树的根目录(查找相应头文件和库用)
SYSROOT="${TOOLCHAIN}/sysroot"

# armv7-a
OUTPUT_FOLDER="armeabi-v7a"
ARCH="arm"
CPU="armv7-a"
TOOL_CPU_NAME=armv7a
TOOL_PREFIX="$TOOLCHAIN/bin/${TOOL_CPU_NAME}-linux-androideabi"
OPTIMIZE_CFLAGS="-march=$CPU"

# arm64-v8a，这个指令集最低支持api21
# OUTPUT_FOLDER="arm64-v8a"
# ARCH="aarch64"
# CPU="armv8-a"
# TOOL_CPU_NAME=aarch64
# TOOL_PREFIX="$TOOLCHAIN/bin/${TOOL_CPU_NAME}-linux-android"
# OPTIMIZE_CFLAGS="-march=$CPU"

# x86
# OUTPUT_FOLDER="x86"
# ARCH="x86"
# CPU="x86"
# TOOL_CPU_NAME="i686"
# TOOL_PREFIX="$TOOLCHAIN/bin/${TOOL_CPU_NAME}-linux-android"
# OPTIMIZE_CFLAGS="-march=i686 -mtune=intel -mssse3 -mfpmath=sse -m32"

# x86_64，这个指令集最低支持api21
# OUTPUT_FOLDER="x86_64"
# ARCH="x86_64"
# CPU="x86_64"
# TOOL_CPU_NAME="x86_64"
# TOOL_PREFIX="$TOOLCHAIN/bin/${TOOL_CPU_NAME}-linux-android"
# OPTIMIZE_CFLAGS="-march=$CPU"

# 输出目录
PREFIX="${PWD}/android-build/$OUTPUT_FOLDER"
# so的输出目录， --libdir=$LIB_DIR 可以不用指定，默认会生成在$PREFIX/lib目录中
#LIB_DIR="${PWD}/android/libs/$OUTPUT_FOLDER"
# 编译器
CC="${TOOL_PREFIX}${API}-clang"
CXX="${TOOL_PREFIX}${API}-clang++"

# 定义执行configure的shell方法
function build_android() {
    ./configure \
        --prefix=$PREFIX \
        --enable-shared \
        --disable-static \
        --enable-jni \
        --disable-doc \
        --disable-programs \
        --disable-symver \
        --target-os=android \
        --arch=$ARCH \
        --cpu=$CPU \
        --cc=$CC \
        --cxx=$CXX \
        --enable-cross-compile \
        --sysroot=$SYSROOT \
        --extra-cflags="-Os -fpic $OPTIMIZE_CFLAGS" \
        --extra-ldflags="" \
        --disable-asm \
        $COMMON_FF_CFG_FLAGS
    make clean
    make -j8
    make install
}

build_android

修改NDK位置以及OUTPUT位置，执行 sh xxx.sh 进行编译等待完成即可。

2.复制项目编译出来的so文件到android项目中对应位置 libs/armeabi-v7a 或 libs/arm64-v8a

3.修改项目app模块build.gradle文件，如下：

android {
    defaultConfig {
        .... //省略一些内容
        ndk {
            abiFilters 'armeabi-v7a'
        }
        sourceSets {
            main {
                jniLibs.srcDirs = ['libs']
            }
        }
    }
    externalNativeBuild {
        cmake {
            path "src/main/cpp/CMakeLists.txt"
            version "3.10.2"
        }
    }
}

4.位于cpp目录下CMakeLists.txt文件的配置，用于链接 ffmpeg库，如下配置：

# 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("jni")

# 配置.h文件的目录，这里是直接放在cpp中的，文件目录名叫includes
include_directories(includes)
# 配置so文件的位置目录，项目中放在app/libs下的，应如下设置
set(LINK_DIR ${CMAKE_SOURCE_DIR}/../../../libs/${CMAKE_ANDROID_ARCH_ABI})
# 链接响应的so库
link_directories(${LINK_DIR})
# 声明全局的SO库的位置信息，方便后面引入该库
file(GLOB SO_DIR ${LINK_DIR}/*.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
        -Wl,--start-group  # 设置库的引入不分先后顺序
        ${SO_DIR}
        -Wl,--end-group
        # Links the target library to the log library
        # included in the NDK.
        ${log-lib}
        z)