为Android NDK构建FFMpeg给我.a而不是.so文件

Question

I'm a Mac user. I followed this tutorial : http://www.roman10.net/how-to-build-ffmpeg-with-ndk-r9/ to build FFMpeg for Android using NDK

I'm using FFMpeg 2.1 and NDK r9 .

Here is my build_android.sh file in my FFMepg folder which is in my $NDK/sources folder :

#!/bin/bash

NDK=$HOME/Desktop/adt/android-ndk
SYSROOT=$NDK/platforms/android-8/arch-arm/
TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/darwin-x86_64
function build_one
{
./configure \
    --prefix=$PREFIX \
    --enable-shared \
    --disable-static \
    --disable-doc \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-ffprobe \
    --disable-ffserver \
    --disable-avdevice \
    --disable-doc \
    --disable-symver \
    --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
    --target-os=linux \
    --arch=arm \
    --enable-cross-compile \
    --sysroot=$SYSROOT \
    --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
    --extra-ldflags="$ADDI_LDFLAGS" \
    $ADDITIONAL_CONFIGURE_FLAG
make clean
make
make install
}
CPU=arm
PREFIX=$(pwd)/android/$CPU 
ADDI_CFLAGS="-marm"
build_one

Evrything is compiling fine but at the end I get .a files whereas in the tutorial I should get .so files.

What is wrong with what I did ? The only thing that changes is :

TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/darwin-x86_64

which is :

TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64

in the tutorial.

Answer 1

I tried your approach but not suceeded. Change to --disable-shared and enable-static

After your make install add following

$TOOLCHAIN/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o
$TOOLCHAIN/bin/arm-linux-androideabi-ld -rpath-link=$SYSROOT/usr/lib -L$SYSROOT/usr/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog -lx264  --warn-once  --dynamic-linker=/system/bin/linker $TOOLCHAIN/lib/gcc/arm-linux-androideabi/4.4.3/libgcc.a

This worked for me! This approach is building .a and linking all .a to .so file. Change libffmpeg.so to any name you want.

Answer 2

You should use the make that comes with NDK:

...
$NDK/prebuilt/darwin-x86_64/bin/make clean
$NDK/prebuilt/darwin-x86_64/bin/make
$NDK/prebuilt/darwin-x86_64/bin/make install

BTW, you can put ffmpeg sources anywhere, no need to keep it under NDK/sources .