Android平台移植FFMPEG媒体解码库

交叉编译环境：Ubuntu12.04 （32位）
FFMPEG版本：ffmpeg-2.8.1.tar.bz2
Android NDK开发包：android-ndk32-r10b-linux-x86.tar.bz2

</pre><pre name="code" class="plain">#!/bin/bash
#
# FFmpeg-Android, a bash script to build FFmpeg for Android.
#
# Copyright (c) 2012 Cedric Fung <[email protected]>
#
# FFmpeg-Android will build FFmpeg for Android automatically,
# with patches from VPlayer's Android version <https://vplayer.net/>.
#
# FFmpeg-Android is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 3 of the License, or (at your option) any later version.

# FFmpeg-Android is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.

# You should have received a copy of the GNU Lesser General Public
# License along with FFmpeg-Android; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#
#
# Instruction:
#
# 0. Install git and Android ndk
# 1. $ export ANDROID_NDK=/path/to/your/android-ndk
# 2. $ ./FFmpeg-Android.sh
# 3. libffmpeg.so will be built to build/ffmpeg/{neon,armv7,vfp,armv6}/
#
#

DEST=`pwd`/build/ffmpeg && rm -rf $DEST
SOURCE=`pwd`/ffmpeg
ANDROID_NDK=/work/FFMPEG/android-ndk-r10b

TOOLCHAIN=/work/FFMPEG/toolchain
SYSROOT=$TOOLCHAIN/sysroot/
#$ANDROID_NDK/build/tools/make-standalone-toolchain.sh --platform=android-14 --install-dir=$TOOLCHAIN

export PATH=$TOOLCHAIN/bin:$PATH
export CC="ccache arm-linux-androideabi-gcc"
export LD=arm-linux-androideabi-ld
export AR=arm-linux-androideabi-ar

CFLAGS="-O3 -Wall -mthumb -pipe -fpic -fasm \
        -finline-limit=300 -ffast-math \
        -fstrict-aliasing -Werror=strict-aliasing \
        -fmodulo-sched -fmodulo-sched-allow-regmoves \
        -Wno-psabi -Wa,--noexecstack \
        -D__ARM_ARCH_5__ -D__ARM_ARCH_5E__ -D__ARM_ARCH_5T__ -D__ARM_ARCH_5TE__ \
        -DANDROID -DNDEBUG"

FFMPEG_FLAGS="--prefix=/work/FFMPEG/ffmpeg_android/ \
              --target-os=android \
              --arch=arm \
              --enable-cross-compile \
              --cross-prefix=arm-linux-androideabi- \
              --enable-shared \
              --disable-symver \
              --disable-doc \
              --disable-ffplay \
              --disable-ffmpeg \
              --disable-ffprobe \
              --disable-ffserver \
              --disable-avdevice \
              --disable-avfilter \
              --disable-encoders \
              --disable-muxers \
              --disable-bsfs \
              --disable-filters \
              --disable-devices \
              --disable-everything \
              --enable-protocols  \
              --enable-parsers \
              --enable-demuxers \
              --disable-demuxer=sbg \
              --enable-decoders \
              --enable-network \
              --enable-swscale  \
              --enable-version3 \
              --disable-inline-asm \
              --disable-yasm \
              --disable-mips32r2 \
              --disable-mipsdspr1 \
              --disable-mipsdspr2 \
              --disable-mipsfpu \
              --disable-fast-unaligned \
              --disable-debug \
              --disable-xmm-clobber-test \
              --enable-decoder=h264 \
              --enable-decoder=mpeg4 \
              --enable-decoder=mjpeg \
              --enable-demuxer=h264 \
              --enable-demuxer=mpeg4 \
              --enable-demuxer=mjpeg \
              --enable-parser=h264 \
              --enable-memalign-hack \
              --disable-asm \
              --disable-altivec \
              --disable-amd3dnow \
              --disable-amd3dnowext \
              --enable-mmx \
              --enable-mmxext \
              --disable-sse \
              --disable-sse2 \
              --disable-sse3 \
              --disable-ssse3 \
              --disable-sse4 \
              --disable-fma4"


for version in neon armv7 vfp armv6; do

cd $SOURCE

case $version in
neon)
    EXTRA_CFLAGS="-march=armv7-a -mfpu=neon -mfloat-abi=softfp -mvectorize-with-neon-quad"
    EXTRA_LDFLAGS="-Wl,--fix-cortex-a8"
    ;;
armv7)
    EXTRA_CFLAGS="-march=armv7-a -mfpu=vfpv3-d16 -mfloat-abi=softfp"
    EXTRA_LDFLAGS="-Wl,--fix-cortex-a8"
    ;;
vfp)
    EXTRA_CFLAGS="-march=armv6 -mfpu=vfp -mfloat-abi=softfp"
    EXTRA_LDFLAGS=""
    ;;
armv6)
    EXTRA_CFLAGS="-march=armv6"
    EXTRA_LDFLAGS=""
    ;;
*)
    EXTRA_CFLAGS=""
    EXTRA_LDFLAGS=""
    ;;
esac

PREFIX="$DEST/$version" && mkdir -p $PREFIX
FFMPEG_FLAGS="$FFMPEG_FLAGS --prefix=$PREFIX"

./configure $FFMPEG_FLAGS --extra-cflags="$CFLAGS $EXTRA_CFLAGS" --extra-ldflags="$EXTRA_LDFLAGS" | tee $PREFIX/configuration.txt
cp config.* $PREFIX
[ $PIPESTATUS == 0 ] || exit 1

make clean
make -j4 || exit 1
make install || exit 1

rm libavcodec/inverse.o
$CC -lm -lz -shared --sysroot=$SYSROOT -Wl,--no-undefined -Wl,-z,noexecstack $EXTRA_LDFLAGS libavutil/*.o libavutil/arm/*.o libavcodec/*.o libavcodec/arm/*.o libavformat/*.o libswresample/*.o libswscale/*.o -o $PREFIX/libffmpeg.so

cp $PREFIX/libffmpeg.so $PREFIX/libffmpeg-debug.so
arm-linux-androideabi-strip --strip-unneeded $PREFIX/libffmpeg.so

done

注意：
1、直接运行上面的脚本会出错，提示如下：
arm-linux-androideabi-gcc is unable to create an executable file.
C compiler test failed.

解决办法：
执行以上脚本前，先在命令行上执行以下命令把对NDK包中的交叉编译工具链独立提取出来到指定的目录：
/work/FFMPEG/android-ndk-r10b/build/tools/make-standalone-toolchain.sh --platform=android-14 --install-dir=/work/FFMPEG/toolchain/

2、target-os=android，此处不要再用linux了。

3、注意NDK的版本，如果应用代码中使用的是32位系统库，则交叉编译的时候就应该用32位的NDK开发包。