編譯FFmpeg for iOS

2項依賴：

gas-preprocessor（見附錄：gas-preprocessor簡介）

yasm 1.2.0

如果要內建x264和fdk_aac，需要先編譯x264和fdk_aac。

Usage（用root執行）

To build everything:

./build-ffmpeg.sh

To build arm64 libraries:

./build-ffmpeg.sh arm64

To build fat libraries for armv7 and x86_64 (x86_64 是64-bit simulator 模拟器):

./build-ffmpeg.sh armv7 x86_64

To build fat libraries from separately built thin libraries:

./build-ffmpeg.sh lipo

You should link your app with

libz.dylib

libbz2.dylib

libiconv.dylib

最終輸出FFmpeg-iOS（我已改成fat-FFmpeg），可以在腳本裡指定需要的平台

#ARCHS="arm64 armv7 x86_64 i386"

問題：

1，編譯失敗，sh中有個

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" 通路不了

執行到這一句說明沒有安裝yasm，而安裝yasm，需要用到homebrew，是以執行上面語句安裝homebrew時報錯了。

解決：安裝yasm，先安裝homebrew，參見附錄：homebrew的安裝與使用

2，xcrun -sdk iphoneos clang is unable to create an executable file 

C compiler test failed.

解決：去掉bitcode，如下：

CFLAGS="$CFLAGS -mios-version-min=$DEPLOYMENT_TARGET -fembed-bitcode"

3，如果內建了fdk_aac，需要添加：enable-nonfree

4，gas-preprocessor.pl的位置在usr/local/bin/，之前在/usr/bin下。不然會報GNU assembler not found gas-preprocessor

附錄：

一，homebrew的安裝與使用

套件管理器

安裝：

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

不能用root執行

常用指令：

查找軟體包

brew search wget

安裝軟體包

brew install wget

删除軟體包

brew remove wget

檢視軟體包資訊

brew info wget

列出軟體包的依賴關系

brew deps wget

更新brew

brew update

二，gas-preprocessor簡介

https://github.com/libav/gas-preprocessor

Perl script that implements a subset of the GNU as preprocessor that Apple's as doesn't

To configure Libav for iOS: ./configure --enable-cross-compile --arch=arm --target-os=darwin --cc='clang -arch armv7' --sysroot=$(xcrun --sdk iphoneos --show-sdk-path) --cpu=cortex-a8 --enable-pic If deploying to all generations, it's recommended to do separate out-of-tree builds for each architecture, then lipo together the resulting libs. For instance, assuming separate builds in armv6 and armv7: lipo -create -arch armv6 armv6/libavcodec/libavcodec.a -arch armv7 armv7/libavcodec/libavcodec.a -output universal/libavcodec.a and similar for each library. Then in XCode, make sure to build for both armv6 and armv7. If you only care about one generation (since the armv6 devices are too slow for instance), then lipo is unnecessary of course.

還一個原始版本https://github.com/yuvi/gas-preprocessor

To configure ffmpeg for the iPhone 3gs and iPod touch 3g: ./configure --enable-cross-compile --arch=arm --target-os=darwin --cc='/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc -arch armv7' --sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.0.sdk --cpu=cortex-a8 --enable-pic To configure ffmpeg for all other iPhones and iPods: ./configure --enable-cross-compile --arch=arm --target-os=darwin --cc='/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc -arch armv6' --sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.0.sdk --cpu=arm1176jzf-s Make sure to replace the iPhone SDK version with the version that you're using. Pre-3.0 versions aren't supported and probably won't work. If deploying to all generations, it's recommended to do separate out-of-tree builds for each architecture, then lipo together the resulting libs. For instance, assuming separate builds in armv6 and armv7: lipo -create -arch armv6 armv6/libavcodec/libavcodec.a -arch armv7 armv7/libavcodec/libavcodec.a -output universal/libavcodec.a and similar for each library. Then in XCode, make sure to build for both armv6 and armv7. If you only care about one generation (since the armv6 devices are too slow for instance), then lipo is unnecessary of course.

我的腳本:

庫裁剪：支援libfdk_aac+libx264 編碼和aac+h264解碼：

藝搜參考：

腳本： https://github.com/kewlbear/FFmpeg-iOS-build-script   

Homebrew：http://linfan.info/blog/2012/02/25/homebrew-installation-and-usage/

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