ffmpeg iOS 编译

编译模拟器版本
1 到https://github.com/yuvi/gas-preprocessor下载gas-preprocessor.p并拷贝到/usr/sbin目录中
2 下载ffmpeg源码。
http://ffmpeg.org/download.html
https://github.com/FFmpeg/FFmpeg
3 解压源码，cd到源码目录下
4 创建文件config_i386.sh，其内容如下

#!/bin/tcsh -f
set targetDir="../ffmpeg-libs/i386"
if (! -d $targetDir ) mkdir $targetDir

rm -f $targetDir/*.a

make clean

#./configure --arch=i386 --extra-cflags='-arch i386' --extra-ldflags='-arch i386'  --disable-encoders --disable-debug --disable-mmx

./configure \
--cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc \
--as='gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc' \
--nm="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/nm" \
--sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk \
--target-os=darwin \
--arch=i386 \
--cpu=i386 \
--extra-cflags='-arch i386 -miphoneos-version-min=4.3 -mdynamic-no-pic' \
--extra-ldflags='-arch i386 -miphoneos-version-min=4.3 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk' \
--prefix=compiled/i386 \
--enable-cross-compile \
--enable-nonfree \
--enable-gpl \
--disable-armv5te \
--disable-swscale-alpha \
--disable-doc \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-ffserver \
--disable-asm \
--disable-debug

make

mv libavcodec/libavcodec.a $targetDir
mv libavdevice/libavdevice.a $targetDir
mv libavformat/libavformat.a $targetDir
mv libavutil/libavutil.a $targetDir
mv libswscale/libswscale.a $targetDir

5 执行config_i386.sh进行配置和编译
编译完成后，可以在$targetDir找到相应的静态库文件

编译真机版
前3步同上
第4步：创建文件config_armv7，其内容如下

#!/bin/tcsh -f
set targetDir="../ffmpeg-libs/armv7"
if (! -d $targetDir ) mkdir $targetDir

rm -f $targetDir/*.a

make clean

./configure \
--cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc \
--as='gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc' \
--nm="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/nm" \
--sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk \
--target-os=darwin \
--arch=arm \
--cpu=cortex-a8 \
--extra-cflags='-arch armv7 -miphoneos-version-min=4.3 -mdynamic-no-pic' \
--extra-ldflags='-arch armv7 -miphoneos-version-min=4.3 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk' \
--prefix=compiled/armv7 \
--enable-cross-compile \
--enable-nonfree \
--enable-gpl \
--disable-armv5te \
--disable-swscale-alpha \
--disable-doc \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-ffserver \
--disable-asm \
--disable-debug

make

mv libavcodec/libavcodec.a $targetDir
mv libavformat/libavformat.a $targetDir
mv libavutil/libavutil.a $targetDir
mv libswscale/libswscale.a $targetDir

第5步：
执行config_armv7进行配置和编译，编译完成后可以在$targetDir找到相应的静态库文件