使用Android NDK构建的ffmpeg4.1.3比linux gcc大4倍

Question

FFmpeg版本： 4.1.3
android-ndk-r19c， 44 MB （armeabi-v7a）
gcc-7： 9.7 MB （x86_64）

配置几乎相同：

对于android-ndk-19c：
我没有链接x264，在Linux x86_64下，x264是链接的，因此理论上Linux X86_64链接的代码比android的更多。

#!/bin/bash

# set the toolchain
TOOLCHAIN=$NDK_HOME/toolchains/llvm/prebuilt/linux-x86_64
CROSS_PREFIX=$TOOLCHAIN/bin/arm-linux-androideabi-
rm -f $(pwd)/compat/strtod.o
function build_one
{
#configure ffmpeg w/o libx264
./configure \
    --prefix=$PREFIX \
    --disable-everything --disable-programs --disable-doc \
    --enable-ffmpeg --enable-jni \
    --enable-encoder=aac \
    --enable-encoder=mpeg4 \
    --enable-encoder=pcm_u16le --enable-encoder=pcm_s16le \
    --enable-encoder=yuv4 \
    --enable-encoder=rawvideo \
    --enable-encoder=wrapped_avframe \
    --enable-decoder=aac --enable-decoder=aac_at --enable-decoder=aac_fixed \
    --enable-decoder=aac_latm \
    --enable-decoder=ac3 --enable-decoder=ac3_at --enable-decoder=ac3_fixed \
    --enable-decoder=avs \
    --enable-decoder=eac3 \
    --enable-decoder=eac3_at \
    --enable-decoder=h263 \
    --enable-decoder=h264 \
    --enable-decoder=hevc \
    --enable-decoder=mp1 --enable-decoder=mp1_at --enable-decoder=mp1float \
    --enable-decoder=mp2 \
    --enable-decoder=mp2_at \
    --enable-decoder=mp2float \
    --enable-decoder=mp3 --enable-decoder=mp3_at --enable-decoder=mp3float \
    --enable-decoder=vp8 --enable-decoder=vp9 \
    --enable-decoder=mpeg1video \
    --enable-decoder=mpeg2video \
    --enable-decoder=mpeg4 \
    --enable-decoder=mpegvideo \
    --enable-decoder=pcm_u16le --enable-decoder=pcm_s16le \
    --enable-decoder=yuv4 \
    --enable-decoder=rawvideo \
    --enable-decoder=wrapped_avframe \
    --enable-muxer=mpegts \
    --enable-muxer=mp4 \
    --enable-muxer=matroska --enable-muxer=matroska_audio --enable-muxer=webm \
    --enable-muxer=h264 \
    --enable-muxer=hevc \
    --enable-muxer=rawvideo \
    --enable-muxer=adts \
    --enable-muxer=yuv4mpegpipe \
    --enable-demuxer=aac \
    --enable-demuxer=ac3 \
    --enable-demuxer=eac3 \
    --enable-demuxer=m4v \
    --enable-demuxer=matroska \
    --enable-demuxer=mp3 \
    --enable-demuxer=mpegps \
    --enable-demuxer=mpegts \
    --enable-demuxer=mpegvideo \
    --enable-demuxer=h263 \
    --enable-demuxer=h264 \
    --enable-demuxer=hevc \
    --enable-demuxer=mov \
    --enable-demuxer=rawvideo \
    --enable-demuxer=yuv4mpegpipe \
    --enable-parser=aac \
    --enable-parser=aac_latm \
    --enable-parser=ac3 \
    --enable-parser=h263 \
    --enable-parser=h264 \
    --enable-parser=hevc \
    --enable-parser=mpeg4video \
    --enable-parser=mpegaudio \
    --enable-parser=mpegvideo \
    --enable-parser=vp8 \
    --enable-parser=vp9 \
    --enable-protocol=file \
    --enable-bsf=aac_adtstoasc \
    --enable-bsf=h264_mp4toannexb \
    --enable-bsf=hevc_mp4toannexb \
    --enable-bsf=mpeg4_unpack_bframes \
    --enable-filter=scale \
    --disable-zlib --disable-xlib --disable-iconv --disable-alsa \
    --disable-libxcb_shape --disable-libxcb_xfixes --disable-lzma \
    --disable-sdl2 --disable-sndio --disable-bzlib --disable-libxcb \
    --disable-hwaccels \
    --target-os=android \
    --enable-cross-compile \
    --toolchain=clang-usan \
    --cross-prefix=$CROSS_PREFIX \
    --cc=$TOOLCHAIN/bin/armv7a-linux-androideabi28-clang \
    --cxx=$TOOLCHAIN/bin/armv7a-linux-androideabi28-clang++ \
    --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
    --extra-ldflags="$ADDI_LDFLAGS" \
    --sysroot=$TOOLCHAIN/sysroot $ADDITIONAL_CONFIG_FLAG
make clean
make -j4
make install
}

CPU=armeabi-v7a
mkdir -p $(pwd)/android/$CPU
PREFIX=$(pwd)/android/$CPU 
ADDI_CFLAGS=""
ADDI_LDFLAGS="-Wl,-Bsymbolic"
ADDITIONAL_CONFIG_FLAG="--arch=arm"
build_one

完成并将其剥离后，会生成44MB的ffmpeg，这太可怕了，但我对此一无所知，我尝试添加-Os CFLAGS，但这无济于事。

这是X86_64：

#!/bin/bash

configure()
{
    CPU=$1
    HOST=linux
    PREFIX=$(pwd)/$HOST/$CPU 
    ADDI_CFLAGS="-I$(pwd)/../x264-stable/$HOST/$CPU/include"
    ADDI_LDFLAGS="-L$(pwd)/../x264-stable/$HOST/$CPU/lib"
    ADDITIONAL_CONFIG_FLAG=""

    ./configure \
    --prefix=$PREFIX \
    --disable-everything --disable-programs --disable-doc \
    --enable-ffmpeg --enable-libx264 --enable-gpl \
    --enable-encoder=aac \
    --enable-encoder=libx264 \
    --enable-encoder=mpeg4 \
    --enable-encoder=pcm_u16le --enable-encoder=pcm_s16le \
    --enable-encoder=yuv4 \
    --enable-encoder=rawvideo \
    --enable-encoder=wrapped_avframe \
    --enable-decoder=aac \
    --enable-decoder=aac_at \
    --enable-decoder=aac_fixed \
    --enable-decoder=aac_latm \
    --enable-decoder=ac3 --enable-decoder=ac3_at --enable-decoder=ac3_fixed \
    --enable-decoder=avs \
    --enable-decoder=eac3 \
    --enable-decoder=eac3_at \
    --enable-decoder=h263 \
    --enable-decoder=h264 \
    --enable-decoder=hevc \
    --enable-decoder=mp1 --enable-decoder=mp1_at --enable-decoder=mp1float \
    --enable-decoder=mp2 \
    --enable-decoder=mp2_at \
    --enable-decoder=mp2float \
    --enable-decoder=mp3 --enable-decoder=mp3_at --enable-decoder=mp3float \
    --enable-decoder=vp8 --enable-decoder=vp9 \
    --enable-decoder=mpeg1video \
    --enable-decoder=mpeg2video \
    --enable-decoder=mpeg4 \
    --enable-decoder=mpegvideo \
    --enable-decoder=pcm_u16le --enable-decoder=pcm_s16le \
    --enable-decoder=yuv4 \
    --enable-decoder=rawvideo --enable-decoder=wrapped_avframe \
    --enable-muxer=mpegts \
    --enable-muxer=mp4 \
    --enable-muxer=matroska --enable-muxer=matroska_audio --enable-muxer=webm \
    --enable-muxer=h264 \
    --enable-muxer=hevc \
    --enable-muxer=rawvideo \
    --enable-muxer=adts \
    --enable-muxer=yuv4mpegpipe \
    --enable-demuxer=aac \
    --enable-demuxer=ac3 \
    --enable-demuxer=eac3 \
    --enable-demuxer=m4v \
    --enable-demuxer=matroska \
    --enable-demuxer=mp3 \
    --enable-demuxer=mpegps \
    --enable-demuxer=mpegts \
    --enable-demuxer=mpegvideo \
    --enable-demuxer=h263 \
    --enable-demuxer=h264 \
    --enable-demuxer=hevc \
    --enable-demuxer=mov \
    --enable-demuxer=rawvideo \
    --enable-demuxer=yuv4mpegpipe \
    --enable-parser=aac \
    --enable-parser=aac_latm \
    --enable-parser=ac3 \
    --enable-parser=h263 \
    --enable-parser=h264 \
    --enable-parser=hevc \
    --enable-parser=mpeg4video \
    --enable-parser=mpegaudio \
    --enable-parser=mpegvideo \
    --enable-parser=vp8 \
    --enable-parser=vp9 \
    --enable-protocol=file \
    --enable-bsf=aac_adtstoasc \
    --enable-bsf=h264_mp4toannexb \
    --enable-bsf=hevc_mp4toannexb \
    --enable-bsf=mpeg4_unpack_bframes \
    --enable-filter=scale \
    --disable-zlib --disable-xlib --disable-iconv \
    --disable-alsa --disable-libxcb_shape --disable-libxcb_xfixes \
    --disable-lzma --disable-sdl2 --disable-sndio \
    --disable-bzlib --disable-libxcb \
    --disable-hwaccels \
    --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
    --extra-ldflags="$ADDI_LDFLAGS"
}

build()
{
    make clean
    cpu=$1

    echo "build $cpu"

    configure $cpu
    make -j4
    make install
}

build linux_x86_64