Linux下编译Android平台的ffmpeg库

在Linux平台下编译要方便些，我这里使用的环境是Ubutunu。

首先你需要Android-NDK 和ffmpeg源码，不同的版本里的文件结构有所差别，编译环境也有所不同。我这里使用的是以下两个版本：

• android-ndk-r9-linux-x86.tar.bz2
• ffmpeg-2.2.15.tar.bz2

---

1. 解压 android-ndk-r9-linux-x86.tar.bz2

第一步：下载 https://dl.google.com/android/ndk/android-ndk-r9-linux-x86.tar.bz2
cd ~
tar xvf android-ndk-r9-linux-x86.tar.bz2

我的解压路径为 ~/android-ndk-r9/

2. 解压ffmpeg

cd ~
tar xvf ffmpeg-2.2.15.tar.bz2
~/ffmpeg-2.2.15/

3. 在~/ffmpeg-2.2.15/ 下创建build_android.sh

#!/bin/bash####################################################### Usage:# put this script in top of FFmpeg source tree# ./build_android# It generates binary for following architectures:# ARMv6 # ARMv6+VFP # ARMv7+VFPv3-d16 (Tegra2) # ARMv7+Neon (Cortex-A8)# Customizing:# 1. Feel free to change ./configure parameters for more features# 2. To adapt other ARM variants# set $CPU and $OPTIMIZE_CFLAGS # call build_one######################################################NDK=~/android-ndk-r9PLATFORM=$NDK/platforms/android-9/arch-arm/PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86function build_one{    ./configure --target-os=linux \        --prefix=$PREFIX \        --enable-cross-compile \        --extra-libs="-lgcc" \        --arch=arm \        --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \        --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \        --nm=$PREBUILT/bin/arm-linux-androideabi-nm \        --sysroot=$PLATFORM \        --extra-cflags=" -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 -Dipv6mr_interface=ipv6mr_ifindex -fasm -Wno-psabi -fno-short-enums -fno-strict-aliasing -finline-limit=300 $OPTIMIZE_CFLAGS " \        --disable-shared \        --enable-static \        --extra-ldflags="-Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib -lc -lm -ldl -llog" \        --disable-everything \        --enable-demuxer=mov \        --enable-demuxer=h264 \        --disable-ffplay \        --enable-protocol=file \        --enable-avformat \        --enable-avcodec \        --enable-decoder=rawvideo \        --enable-decoder=mjpeg \        --enable-decoder=h263 \        --enable-decoder=mpeg4 \        --enable-decoder=h264 \        --enable-parser=h264 \        --disable-network \        --enable-zlib \        --enable-avfilter \        --disable-avdevice \        $ADDITIONAL_CONFIGURE_FLAG    make clean    make  -j4 install    $PREBUILT/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o    $PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -soname libffmpeg.so -shared -nostdlib  -z noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavformat/libavformat.a libavfilter/libavfilter.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.6/libgcc.a}#arm v6#CPU=armv6#OPTIMIZE_CFLAGS="-marm -march=$CPU"#PREFIX=./android/$CPU #ADDITIONAL_CONFIGURE_FLAG=#build_one#arm v7vfpv3CPU=armv7-aOPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=$CPU "PREFIX=./android/$CPUADDITIONAL_CONFIGURE_FLAG=build_one#arm v7vfp#CPU=armv7-a#OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU "#PREFIX=./android/$CPU-vfp#ADDITIONAL_CONFIGURE_FLAG=#build_one#arm v7n#CPU=armv7-a#OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -march=$CPU -mtune=cortex-a8"#PREFIX=./android/$CPU #ADDITIONAL_CONFIGURE_FLAG=--enable-neon#build_one#arm v6+vfp#CPU=armv6#OPTIMIZE_CFLAGS="-DCMP_HAVE_VFP -mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU"#PREFIX=./android/${CPU}_vfp #ADDITIONAL_CONFIGURE_FLAG=#build_one

chmod +x build_android.sh
./build_android.sh
过一会，就能生成一系列的静态库(libavcode.a 等)和一个动态库libffmpeg.so

在QT中就直接调用libffmpeg.so就可以了。

INCLUDEPATH +=  $$PWD/ffmpeg/includeLIBS += -L$$PWD/ffmpeg/android -lffmpeg

本文中的build_android.sh参考 http://www.roman10.net/how-to-build-ffmpeg-for-android/

根据版本的差异，对build_android.sh作了相应的修改。