macOS10.9+xcode6编译ffmpeg2.4.2 for ios
最近需要用到ffmpeg开发视频相关。在网上找了些编译资源，自己摸索着，总算编译ok了。
因此，记录下苦逼的编译过程，已祭奠我为之逝去的青春。
1、准备工作
首先，到ffmpeg官网下载最新到代码。
然后，https://github.com/lajos/iFrameExtractor 下载这个示例程序。并将里面的 gas-preprocessor.pl 拷贝到 /usr/local/bin 文件夹。
2、编译
首先，附上编译原文：
Build steps
- Download the code using
git clone git://github.com/PinkyJie/iFrameExtractor.git
- Download the latest ffmpeg (0.11.1 tested) using
git clone git://source.ffmpeg.org/ffmpeg.git
-
Put the ffmpeg source code into the folder
ffmpeg -
Copy the perl script
gas-preprocessor.plinto/usr/local/binfolder -
Change directory to your
ffmpegfolder, select your target platform and follow the scripts below
Platforms
armv7(for iPhone 3GS and devices after 3GS)
configure
./configure \
--cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc \
--as='/usr/local/bin/gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc' \
--sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk \
--target-os=darwin \
--arch=arm \
--cpu=cortex-a8 \
--extra-cflags='-arch armv7' \
--extra-ldflags='-arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.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
make clean
make && make install
armv6(for devices before 3GS)
configure
./configure \
--cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc \
--as='/usr/local/bin/gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc' \
--sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk \
--target-os=darwin \
--arch=arm \
--cpu=arm1176jzf-s \
--extra-cflags='-arch armv6' \
--extra-ldflags='-arch armv6 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk' \
--prefix=compiled/armv6 \
--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
make clean
make && make install
i386(for simulator)
configure
./configure \
--cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc \
--as='/usr/local/bin/gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc' \
--sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1.sdk \
--target-os=darwin \
--arch=i386 \
--cpu=i386 \
--extra-cflags='-arch i386' \
--extra-ldflags='-arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1.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
make clean
make && make install
universal(using one *.a files for all platforms)
mkdir -p ./compiled/fat/lib
lipo -output ./compiled/fat/lib/libavcodec.a -create \
-arch armv6 ./compiled/armv6/lib/libavcodec.a \
-arch armv7 ./compiled/armv7/lib/libavcodec.a \
-arch i386 ./compiled/i386/lib/libavcodec.a
lipo -output ./compiled/fat/lib/libavdevice.a -create \
-arch armv6 ./compiled/armv6/lib/libavdevice.a \
-arch armv7 ./compiled/armv7/lib/libavdevice.a \
-arch i386 ./compiled/i386/lib/libavdevice.a
lipo -output ./compiled/fat/lib/libavformat.a -create \
-arch armv6 ./compiled/armv6/lib/libavformat.a \
-arch armv7 ./compiled/armv7/lib/libavformat.a \
-arch i386 ./compiled/i386/lib/libavformat.a
lipo -output ./compiled/fat/lib/libavutil.a -create \
-arch armv6 ./compiled/armv6/lib/libavutil.a \
-arch armv7 ./compiled/armv7/lib/libavutil.a \
-arch i386 ./compiled/i386/lib/libavutil.a
lipo -output ./compiled/fat/lib/libswresample.a -create \
-arch armv6 ./compiled/armv6/lib/libswresample.a \
-arch armv7 ./compiled/armv7/lib/libswresample.a \
-arch i386 ./compiled/i386/lib/libswresample.a
lipo -output ./compiled/fat/lib/libpostproc.a -create \
-arch armv6 ./compiled/armv6/lib/libpostproc.a \
-arch armv7 ./compiled/armv7/lib/libpostproc.a \
-arch i386 ./compiled/i386/lib/libpostproc.a
lipo -output ./compiled/fat/lib/libswscale.a -create \
-arch armv6 ./compiled/armv6/lib/libswscale.a \
-arch armv7 ./compiled/armv7/lib/libswscale.a \
-arch i386 ./compiled/i386/lib/libswscale.a
lipo -output ./compiled/fat/lib/libavfilter.a -create \
-arch armv6 ./compiled/armv6/lib/libavfilter.a \
-arch armv7 ./compiled/armv7/lib/libavfilter.a \
-arch i386 ./compiled/i386/lib/libavfilter.a
The complied static libraries (*.a) lie in theffmpeg/compiled folder.
我想编译armv7。
然后，发现在xcode6下，上述/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc
路径下根本没有gcc，于是找啊找，❤️在
/Applications/Xcode.app/Contents/Developer/usr/bin/gcc
找到了gcc，行啊，试试吧！
编译OK，顺利生成了。a文件。
3、将库拷贝到示例程序中，编译，出错。提示xxxxx undefined symbols for armv7
好吧，又苦苦百度了一遍，度娘没搭理我啊。
突然发现，生成的库文件还有个pkgconfig目录，里面找到那个提示文件libavcodec相关的libavcodec.pc文件，打开一看，没怎么看懂，里面有一行说：
Libs: -L${libdir} -lavcodec -framework CoreVideo -framework Foundation -framework AVFoundation -framework CoreMedia -liconv -lm -lbz2 -lz -pthread
于是，我就在xcode的BuildSettings里面的other link flags里面加入了 －liconv，1⃣️竟然好使！！！
4、我靠，就先这么着吧。
还望过路的大神们，指教指教。