android_ffmpeg_x264

android mac环境下的ffmpeg编译

编译环境是：

Mac 10.12.4 (16E195)
Android Studio 2.3.1
NDK android-ndk-r14b
ffmpeg-3.3.2
x264 lastest

下载地址：

ffmpeg：git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg

x264: git clone http://git.videolan.org/git/x264.git

ndk: https://developer.android.com/ndk/downloads/index.html 需要注意系统，而且不需要配置环境变量

在下载过程中可以去编译脚本

新建脚本: build_with_x264.sh

cd x264
export TEP=/Users/you/Desktop/ffmpeg
export PLATFORM_VERSION=android-9
export ANDROID_NDK=/Users/you/Desktop/android-ndk-r14b #ndk 目录根据你的安装目录
export TOOLCHAIN=$TEP/fftoolchain #toolchain 安装目录
export SYSROOT=$TOOLCHAIN/sysroot/
export PLATFORM=$ANDROID_NDK/platforms/$PLATFORM_VERSION/arch-arm
export PREFIX=$TEP/android-lib #编译结果的目录
export OUT_PREFIX=$TEP/../264fflib
#生成toolchain目录，这一段可以在第一次运行后注释掉
$ANDROID_NDK/build/tools/make-standalone-toolchain.sh \
    --toolchain=arm-linux-androideabi-4.9 \
    --platform=$PLATFORM_VERSION --install-dir=$TOOLCHAIN 
#
./configure \
    --prefix=$PREFIX \
    --enable-static \
    --enable-shared \
    --enable-pic \
    --disable-asm \
    --disable-cli \
    --host=arm-linux \
    --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
    --sysroot=$PLATFORM
make -j8
make install
cd ..
# 加入x264编译库
EXTRA_CFLAGS="-I./android-lib/include" 
EXTRA_LDFLAGS="-L./android-lib/lib"
./configure \
    --target-os=linux \
    --prefix=$OUT_PREFIX \
    --enable-cross-compile \
    --enable-runtime-cpudetect \
    --disable-asm \
    --disable-doc \
    --arch=arm \
    --cc=$TOOLCHAIN/bin/arm-linux-androideabi-gcc \
    --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
    --disable-stripping \
    --nm=$TOOLCHAIN/bin/arm-linux-androideabi-nm \
    --sysroot=$PLATFORM \
    --enable-gpl \
    --enable-static \
    --disable-shared \
    --enable-version3 \
    --enable-small \
    --disable-vda \
    --disable-iconv \
    --disable-encoders \
    --enable-libx264 \
    --enable-encoder=libx264 \
    --disable-muxers \
    --enable-muxer=mov \
    --enable-muxer=ipod \
    --enable-muxer=psp \
    --enable-muxer=mp4 \
    --enable-muxer=avi \
    --disable-decoders \
    --enable-decoder=aac \
    --enable-decoder=aac_latm \
    --enable-decoder=h264 \
    --enable-decoder=mpeg4 \
    --disable-demuxers \
    --enable-demuxer=h264 \
    --enable-demuxer=mov \
    --disable-parsers \
    --enable-parser=aac \
    --enable-parser=ac3 \
    --enable-parser=h264 \
    --disable-protocols \
    --enable-protocol=file \
    --enable-protocol=rtmp \
    --disable-bsfs \
    --enable-bsf=aac_adtstoasc \
    --enable-bsf=h264_mp4toannexb \
    --disable-indevs \
    --enable-zlib \
    --disable-outdevs \
    --disable-ffprobe \
    --disable-ffplay \
    --disable-ffmpeg \
    --disable-ffserver \
    --disable-debug \
    --extra-cflags=$EXTRA_CFLAGS \
    --extra-ldflags=$EXTRA_LDFLAGS
make clean 
make -j8
make install
# 这段解释见后文
$TOOLCHAIN/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -L$OUT_PREFIX/lib -soname libffmpeg.so -shared -nostdlib -Bsymbolic --whole-archive --no-undefined -o $OUT_PREFIX/libffmpeg.so \
    android-lib/lib/libx264.a \
    libavcodec/libavcodec.a \
    libavfilter/libavfilter.a \
    libswresample/libswresample.a \
    libavformat/libavformat.a \
    libavutil/libavutil.a \
    libswscale/libswscale.a \
    libpostproc/libpostproc.a \
    libavdevice/libavdevice.a \
    -lc -lm -lz -ldl -llog --dynamic-linker=/system/bin/linker $TOOLCHAIN/lib/gcc/arm-linux-androideabi/4.9.x/libgcc.a

等待前面的2个源码下载完成后，修改下文件结构

ffmpeg

—x264

—build_with_x264.sh

至此，准备工作完成，接下来是重点，开始编译…

cd ffmpeg

chmod +x build_with_x264.sh

sh ./build_with_x264.sh

……

中间可能出现多次warning，无视就好。。。

最终会出现一下代码结构：

说明编译ok

接下来是导入as，网上很多文章都是用旧的jni方式，而studio从2.2开始引入cmake的方式来更好的加载控制c代码

cmake最大的有点就是可以编辑c代码，并且有代码提示和错误提醒，这对编码来说是非常舒服的

废话不多说，上目录结构先：

gradle在android中追加

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.ffmpegmy"
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        externalNativeBuild {
            cmake {
                cppFlags ""
                abiFilters "armeabi"
            }
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    sourceSets.main {
        jniLibs.srcDirs = ['libs']
        jni.srcDirs = []
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}

cmake文件：

set(distribution_DIR ${CMAKE_SOURCE_DIR}/../../../../libs)
add_library( libffmpeg
             SHARED
             IMPORTED )
set_target_properties( libffmpeg
                       PROPERTIES IMPORTED_LOCATION
                       ../../../../libs/${ANDROID_ABI}/libffmpeg.so )
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")
include_directories(libs/include)
target_link_libraries( # Specifies the target library.
                       native-lib libffmpeg
                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

native-lib.cpp:

#include <jni.h>
#include <string>
extern "C"
{
#include <libavfilter/avfilter.h>
JNIEXPORT jstring JNICALL
Java_com_ffmpegmy_MainActivity_stringFromJNI(
        JNIEnv *env,
        jobject /* this */) {
    char info[40000] = {0};
    avfilter_register_all();
    AVFilter *f_temp = (AVFilter *)avfilter_next(NULL);
    while(f_temp != NULL) {
        sprintf(info, "%s%s\n", info, f_temp->name);
        f_temp = f_temp->next;
    }
    return env->NewStringUTF(info);
}
}

参考：
http://blog.csdn.net/byhook/article/details/51971652
https://github.com/dxjia/ffmpeg-compile-shared-library-for-android
http://blog.csdn.net/leixiaohua1020/article/details/47010637
http://zheteng.me/android/2016/05/25/build-ffmpeg-for-android-with-x264/