NDK 提供对 ndk-build 和 CMake 的官方支持

一、Mac平台使用ndk-build的方式，编译针对Android平台的librtmp库

代码的下载地址：https://github.com/yixia/librtmp
仓库的README中描述的很清楚，它只是在rtmpdump中添加编译脚本

git://git.ffmpeg.org/rtmpdump mirror, only add build librtmp script for Android & iOS

这里的编译参考：https://developer.android.google.cn/ndk/guides/other_build_systems?hl=zh-cn
librtmp属于非 Autoconf make 项目，编译脚本如下：

#!/bin/bash
export NDK=/Users/chengzhen/Library/Android/sdk/ndk/25.1.8937393

# Only choose one of these, depending on your build machine...
export TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/darwin-x86_64
#export TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/linux-x86_64


# Only choose one of these, depending on your device...
export TARGET=aarch64-linux-android
#export TARGET=armv7a-linux-androideabi
#export TARGET=i686-linux-android
#export TARGET=x86_64-linux-android

# Set this to your minSdkVersion.
export API=21

# Set output path
PREFIX=$(pwd)/$TARGET$API

# Build.
make \
    CC="$TOOLCHAIN/bin/clang --target=$TARGET$API" \
    AR=$TOOLCHAIN/bin/llvm-ar \
    RANLIB=$TOOLCHAIN/bin/llvm-ranlib

# Template params
make install SYS=android prefix=$PREFIX CRYPTO= SHARED= XDEF=-DNO_SSL    

二、使用CMake方式，在android studio中集成rtmpdum源码

rtmpdum类似于okhttp，它是rtmp协议的一个实现工具，下载地址：https://github.com/aajanki/rtmpdump?tab=readme-ov-file

下载完成后，把C代码拷贝到工程中，修改CMakeLists.txt文件即可

截屏2024-08-08 21.41.36.png

三、Mac平台编译针对Android平台的xh264库

上面的CMakeLists.txt文件已经集成了xh264，这里讲解下编译

下载地址：https://www.videolan.org/developers/x264.html
xh264属于Autoconf 项目，编译脚本如下：

#!/bin/bash

export NDK=/Users/chengzhen/Library/Android/sdk/ndk/25.1.8937393

TOOLCHAIN_ROOT_DIR=darwin-x86_64
TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/$TOOLCHAIN_ROOT_DIR/
SYSROOT=$TOOLCHAIN/sysroot

API=21
export CC=$TOOLCHAIN/bin/aarch64-linux-android$API-clang
export CXX=$TOOLCHAIN/bin/aarch64-linux-android$API-clang++


LLVM_TOOLCHAIN=$TOOLCHAIN/bin
PKG_CONFIG=/usr/local/bin/pkg-config
export NM=$LLVM_TOOLCHAIN/llvm-nm
export STRIP=$LLVM_TOOLCHAIN/llvm-strip

CPU=armv8-a
PREFIX=$(pwd)/android/$CPU
export CFLAGS="-march=$CPU -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -fno-limit-debug-info  -fPIC"


function build_android {
    ./configure \
    --enable-pic \
    --enable-strip \
    --enable-static \
    --disable-asm \
    --disable-cli \
    --prefix=$PREFIX \
    --cross-prefix=$CROSS_PREFIX \
    --host=aarch64-linux-android \
    --sysroot=$SYSROOT \
    --extra-cflags="$CFLAGS"
    make clean
    make
    make install
}
build_android

四、ffmpeg的编译

这里只是贴一下mac平台编译成功的脚本，本地验证都是通过的

#!/bin/bash 
NDK=/Users/chengzhen/Library/Android/sdk/ndk/25.1.8937393
TOOLCHAIN_ROOT_DIR=darwin-x86_64
TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/$TOOLCHAIN_ROOT_DIR/
API=21
#要编译的ffmpeg内容方法
function build_android {
    echo "Compiling FFmpeg for $CPU" 
    ./configure \
    --prefix=$PREFIX \
    --disable-hwaccels \
    --disable-gpl \
    --disable-postproc \
    --disable-programs \
    --disable-mediacodec \
    --disable-decoder=h264_mediacodec \
    --disable-static \
    --disable-vulkan \
    --disable-doc \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-ffprobe \
    --disable-avdevice \
    --disable-doc \
    --disable-symver \
    --disable-x86asm \
    --disable-filters \
    --enable-cross-compile \
    --enable-jni \
    --enable-shared \
    --cross-prefix=$CROSS_PREFIX \
    --nm=$NM \
    --strip=$STRIP \
    --pkg-config=$PKG_CONFIG \
    --target-os=android \
    --arch=$ARCH \
    --cpu=$CPU \
    --cc=$CC \
    --cxx=$CXX \
    --sysroot=$SYSROOT \
    --extra-cflags="$CFLAGS"
    make clean 
    make 
    make install 
    echo "The Compilation of FFmpeg for $CPU is completed" 
}

#接下来是根据需要来决定
#armv8-a 
ARCH=arm64 
CPU=armv8-a 
CC=$TOOLCHAIN/bin/aarch64-linux-android$API-clang 
CXX=$TOOLCHAIN/bin/aarch64-linux-android$API-clang++
LLVM_TOOLCHAIN=$TOOLCHAIN/bin
#PKG_CONFIG_DIR=/usr/local
PKG_CONFIG=/usr/local/bin/pkg-config
NM=$LLVM_TOOLCHAIN/llvm-nm
STRIP=$LLVM_TOOLCHAIN/llvm-strip
SYSROOT=$TOOLCHAIN/sysroot
CROSS_PREFIX=$TOOLCHAIN/bin/aarch64-linux-android-
PREFIX=$(pwd)/android/$CPU
CFLAGS="-march=$CPU -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -fno-limit-debug-info  -fPIC"
build_android

#x86_64
function fun {
    ARCH=x86_64 
    CPU=x86-64
    CC=$TOOLCHAIN/bin/x86_64-linux-android$API-clang 
    CXX=$TOOLCHAIN/bin/x86_64-linux-android$API-clang++
    LLVM_TOOLCHAIN=$TOOLCHAIN/bin
    PKG_CONFIG_DIR=/usr/local/Cellar/pkg-config/0.29.2_3
    PKG_CONFIG=$PKG_CONFIG_DIR/bin/pkg-config
    NM=$LLVM_TOOLCHAIN/llvm-nm
    STRIP=$LLVM_TOOLCHAIN/llvm-strip
    SYSROOT=$TOOLCHAIN/sysroot 
    CROSS_PREFIX=$TOOLCHAIN/bin/x86_64-linux-android-
    PREFIX=$(pwd)/android/$CPU
    OPTIMIZE_CFLAGS="-march=$CPU"
    build_android
}

五、ffmpeg+rtmp的编译

另外如果想要ffmpeg使用我们自己的rtmp库，需要修改configure文件，注释掉原来ffmpeg自己的rtmp

#enabled librtmp           && require_pkg_config librtmp librtmp librtmp/rtmp.h RTMP_Socket

上面的编译脚本做出相应的修改，添自己的rtmp的头文件和库路径，本地修改后的脚本如下：

#!/bin/bash 
NDK=/Users/chengzhen/Library/Android/sdk/ndk/25.1.8937393
TOOLCHAIN_ROOT_DIR=darwin-x86_64
TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/$TOOLCHAIN_ROOT_DIR/
API=21

RTMP=/Users/chengzhen/Documents/ffmpeg-7.0.1/librtmp_path

#要编译的ffmpeg内容方法
function build_android {
    echo "Compiling FFmpeg for $CPU" 
    ./configure \
    --prefix=$PREFIX \
    --disable-hwaccels \
    --disable-gpl \
    --disable-postproc \
    --disable-programs \
    --disable-mediacodec \
    --disable-decoder=h264_mediacodec \
    --disable-static \
    --disable-vulkan \
    --disable-doc \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-ffprobe \
    --disable-avdevice \
    --disable-doc \
    --disable-symver \
    --disable-x86asm \
    --disable-filters \
    --enable-cross-compile \
    --enable-librtmp \
    --enable-jni \
    --enable-static \
    --cross-prefix=$CROSS_PREFIX \
    --nm=$NM \
    --ar=$AR \
    --ranlib=$RANLIB \
    --strip=$STRIP \
    --pkg-config=$PKG_CONFIG \
    --target-os=android \
    --arch=$ARCH \
    --cpu=$CPU \
    --cc=$CC \
    --cxx=$CXX \
    --sysroot=$SYSROOT \
    --extra-cflags="$CFLAGS" \
    --extra-ldflags="-L$RTMP/lib" \
    --extra-libs="-lrtmp"
    make clean 
    make 
    make install 
    echo "The Compilation of FFmpeg for $CPU is completed" 
}

#接下来是根据需要来决定
#armv8-a 
ARCH=arm64 
CPU=armv8-a 
CC=$TOOLCHAIN/bin/aarch64-linux-android$API-clang 
CXX=$TOOLCHAIN/bin/aarch64-linux-android$API-clang++
LLVM_TOOLCHAIN=$TOOLCHAIN/bin
#PKG_CONFIG_DIR=/usr/local
PKG_CONFIG=/usr/local/bin/pkg-config
NM=$LLVM_TOOLCHAIN/llvm-nm
RANLIB=$LLVM_TOOLCHAIN/llvm-ranlib
AR=$LLVM_TOOLCHAIN/llvm-ar
STRIP=$LLVM_TOOLCHAIN/llvm-strip
SYSROOT=$TOOLCHAIN/sysroot
CROSS_PREFIX=$TOOLCHAIN/bin/aarch64-linux-android-
PREFIX=$(pwd)/android/$CPU
CFLAGS="-I$RTMP/include -march=$CPU -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -fno-limit-debug-info  -fPIC"
build_android