原此出处：

I am pleased to announce that FFmpeg can now be built unpatched for

the iPhone. The process is still not entirely without pain, however.

Here’s how it’s done:

1. Download and install the iPhone SDK 3.1.

2. Get the latest gas-preprocessor and install it in /usr/local/bin

or some other directory in your $PATH.

3. Get the latest FFmpeg from SVN (minimum r20151).

4. Configure FFmpeg with one of the following commands. These give a

clean build with a default installation of iPhone SDK 3.1 on OSX Leopard.

Other versions may vary.

4a. For iPhone 3GS or iPod Touch 3G 32GB/64GB, use this command:

./configure –cc=/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin9-gcc-4.2.1 –as=’gas-preprocessor.pl /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin9-gcc-4.2.1′ –sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.1.sdk –enable-cross-compile –target-os=darwin –arch=arm –cpu=cortex-a8 –enable-pic

4b. For other iPhone or iPod Touch models, use this command:

./configure –cc=/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin9-gcc-4.2.1 –as=’gas-preprocessor.pl /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin9-gcc-4.2.1′ –sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.1.sdk –enable-cross-compile –target-os=darwin –arch=arm –cpu=arm1176jzf-s

5. Run make.

It is important to specify a correct –cpu option, and not merely an

architecture version. Failure to specify the exact CPU will give a

broken build.

For the iPhone 3GS and compatible iPods, –enable-pic is required to

avoid some nasty-looking linker warnings about relocations.

I have not tested the builds on an iPhone/iPod, so there may still be

remaining issues. Please report any problems you encounter.

Many thanks to David Conrad for the gas-preprocessor script, without

which this would not be possible.