Building FFmpeg for IPhone

1. Check out FFmpeg source code 
2. Check out gas-preprocessor 
3. Run configure command 

./configure --cc=/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-gcc-4.2.1 --as='gas-preprocessor.pl /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-gcc-4.2.1' --sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.2.sdk --enable-cross-compile --target-os=darwin --arch=arm --cpu=cortex-a8 --enable-pic --prefix=$HOME/Downloads/ffmpeg/iphone_build 

4. Create a project in Xcode 
5. Add static libraries to Frameworks 
6. Add libz.1.2.3 
7. Add include path and library link path to XCode project 
8. Write some example code 
9. Build and run on real IPhone device

Enable MP3 encoder/decoder
1. Download opencore-amr
2. Run command

./configure --cc=/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-gcc-4.2.1 --as='gas-preprocessor.pl /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-gcc-4.2.1' --sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.2.sdk --enable-cross-compile --target-os=darwin --arch=arm --cpu=cortex-a8 --enable-pic --prefix=$HOME/Downloads/ffmpeg/iphone_build --enable-libopencore-amrnb --enable-version3 --extra-cflags=-I/Users/mhrinc/Downloads/ffmpeg --extra-ldflags=-L/Users/mhrinc/Downloads/ffmpeg/opencore-amrnb --disable-doc --disable-ffserver --disable-ffprobe --disable-swscale --disable-postproc --disable-avfilter --disable-dxva2 --disable-vdpau --disable-vaapi --disable-rdft --disable-mdct --disable-lpc --disable-huffman --disable-golomb --disable-fft --disable-dct --disable-aandct --disable-decoders --disable-encoders --disable-hwaccels --disable-muxers --disable-demuxers --disable-parsers --disable-bsfs --disable-protocols --disable-indevs --disable-outdevs --disable-filters \ 
--enable-decoder=wavpack --enable-encoder=libopencore_amrnb \ 
--enable-muxer=wav --enable-muxer=amr \ 
--enable-demuxer=wav --enable-demuxer=amr \ 
--enable-parser=wav --enable-parser=amr \