前言

为了保证音频格式在多端通用，需要将音频转化为MP3格式，本文讲解了如何使用Shell脚本来编译lame库。

编译脚本

#!/bin/sh

CONFIGURE_FLAGS="--disable-shared --disable-frontend"

ARCHS="arm64 armv7s armv7 x86_64 i386"

MIN_VERSION="10.0"

# directories
SOURCE="lame"
FAT="fat-lame"

SCRATCH="scratch-lame"
# must be an absolute path
THIN=`pwd`/"thin-lame"

COMPILE="y"
LIPO="y"

if [ "$*" ]
then
	if [ "$*" = "lipo" ]
	then
		# skip compile
		COMPILE=
	else
		ARCHS="$*"
		if [ $# -eq 1 ]
		then
			# skip lipo
			LIPO=
		fi
	fi
fi

if [ "$COMPILE" ]
then
	CWD=`pwd`
	for ARCH in $ARCHS
	do
		echo "building $ARCH..."
		mkdir -p "$SCRATCH/$ARCH"
		cd "$SCRATCH/$ARCH"

		if [ "$ARCH" = "i386" -o "$ARCH" = "x86_64" ]
		then
		    PLATFORM="iPhoneSimulator"
		    if [ "$ARCH" = "x86_64" ]
		    then
		    	SIMULATOR="-mios-simulator-version-min=7.0"
                        HOST=x86_64-apple-darwin
		    else
		    	SIMULATOR="-mios-simulator-version-min=5.0"
                        HOST=i386-apple-darwin
		    fi
		else
		    PLATFORM="iPhoneOS"
		    SIMULATOR=
                    HOST=arm-apple-darwin
		fi

		XCRUN_SDK=`echo $PLATFORM | tr '[:upper:]' '[:lower:]'`
		CC="xcrun -sdk $XCRUN_SDK clang -arch $ARCH -miphoneos-version-min=${MIN_VERSION}"
		#AS="$CWD/$SOURCE/extras/gas-preprocessor.pl $CC"
		CFLAGS="-arch $ARCH $SIMULATOR"
		if ! xcodebuild -version | grep "Xcode [1-6]\."
		then
			CFLAGS="$CFLAGS -fembed-bitcode"
		fi
		CXXFLAGS="$CFLAGS"
		LDFLAGS="$CFLAGS"

		CC=$CC $CWD/$SOURCE/configure \
		    $CONFIGURE_FLAGS \
                    --host=$HOST \
		    --prefix="$THIN/$ARCH" \
                    CC="$CC" CFLAGS="$CFLAGS" LDFLAGS="$LDFLAGS"

		make -j3 install
		cd $CWD
	done
fi

if [ "$LIPO" ]
then
	echo "building fat binaries..."
	mkdir -p $FAT/lib
	set - $ARCHS
	CWD=`pwd`
	cd $THIN/$1/lib
	for LIB in *.a
	do
		cd $CWD
		lipo -create `find $THIN -name $LIB` -output $FAT/lib/$LIB
	done

	cd $CWD
	cp -rf $THIN/$1/include $FAT
fi

使用步骤

1. 下载lame
2. 解压后将lame和脚本放到同一文件夹下
3. 修改lame文件夹名称，去除版本号
4. 打开终端，切换到文件夹路径
5. 执行shell脚本
   

注意事项

1. 文件夹路径不要包含中文
2. fat版本包含真机和模拟器