原文地址：http://uberblo.gs/2011/04/iosiphoneos-equalizer-with-libsox-making-it-a-framework
So i've spent the past few weeks with an issue i've been having for quite a while now: Equalization on iOS.
I've tried everything, from AudioUnit, OpenAL and FMod. None of which worked.
- AudioUnit needs formulas which look like they've found on a ship at Roswell..
- OpenAL seems to have all of it's effects ripped out by Apple..
- FMod requires you to know it's own language..
Frustrating.. i even thought about having a Webservice do the job, but that seemed useless for offline usage.
I once again checked out all available options when one thing seemed ideal, sox! You may know sox if you've played around with Audiofile conversion on Linux, especially PBX Setups which require you to convert you favorite MP3s into something your PBX can play.
Anyway, i checked out all libraries, ffmpeg, libav and libsox. Since the command line version of sox delivered nice test results with my equalization attempts, i started to try to get the current release to compile on SDK 4.3. I had massive troubles at first,
but then i found this post.
I have modified the script to make it work plus have it create you a SOX.framework:
#!/bin/bash
################################################################################
#
# Copyright (c) 2008-2009 Christopher J. Stawarz
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#
################################################################################
# Disallow undefined variables
set -u
default_gcc_version=4.2
default_iphoneos_version=4.3
default_macos_version=10.7
GCC_VERSION="${GCC_VERSION:-$default_gcc_version}"
export IPHONEOS_DEPLOYMENT_TARGET="${IPHONEOS_DEPLOYMENT_TARGET:-$default_iphoneos_version}"
export MACOSX_DEPLOYMENT_TARGET="${MACOSX_DEPLOYMENT_TARGET:-$default_macos_version}"
usage ()
{
cat >&2 << EOF
Usage: ${0##*/} [-ht] [-p prefix] target [configure_args]
-h Print help message
-p Installation prefix (default: \$HOME/Developer/Platforms/...)
-t Use 16-bit Thumb instruction set (instead of 32-bit ARM)
The target must be "device" or "simulator". Any additional arguments
are passed to configure.
The following environment variables affect the build process:
GCC_VERSION (default: $default_gcc_version)
IPHONEOS_DEPLOYMENT_TARGET (default: $default_iphoneos_version)
MACOSX_DEPLOYMENT_TARGET (default: $default_macos_version)
EOF
}
while getopts ":hp:t" opt; do
case $opt in
h ) usage ; exit 0 ;;
p ) prefix="$OPTARG" ;;
t ) thumb_opt=thumb ;;
\? ) usage ; exit 2 ;;
esac
done
shift $(( $OPTIND - 1 ))
if (( $# < 1 )); then
make clean
$0 armv6
make clean
$0 armv7
make clean
$0 simulator
make clean
lipo -create iOS-*/lib/libsox.a -o SOX.framework
exit
#usage
#exit 2
fi
target=$1
shift
case $target in
armv6)
arch=armv6
platform=iPhoneOS
extra_cflags="-m${thumb_opt:-no-thumb} -mthumb-interwork"
;;
armv7)
arch=armv7
platform=iPhoneOS
extra_cflags="-m${thumb_opt:-no-thumb} -mthumb-interwork"
;;
simulator)
arch=i386
platform=iPhoneSimulator
extra_cflags="-D__IPHONE_OS_VERSION_MIN_REQUIRED=${IPHONEOS_DEPLOYMENT_TARGET%%.*}0000"
;;
* )
usage
exit 2
esac
platform_dir="/Developer/Platforms/${platform}.platform/Developer"
platform_bin_dir="${platform_dir}/usr/bin"
platform_sdk_dir="${platform_dir}/SDKs/${platform}${IPHONEOS_DEPLOYMENT_TARGET}.sdk"
prefix="${prefix:-`pwd`/iOS-${IPHONEOS_DEPLOYMENT_TARGET}-$target}"
export CC="${platform_bin_dir}/gcc-${GCC_VERSION}"
export CFLAGS="-arch ${arch} -pipe -Os -gdwarf-2 -isysroot ${platform_sdk_dir} ${extra_cflags}"
export LDFLAGS="-arch ${arch} -isysroot ${platform_sdk_dir}"
export CXX="${platform_bin_dir}/g++-${GCC_VERSION}"
export CXXFLAGS="${CFLAGS}"
export CPP="/Developer/usr/bin/cpp-${GCC_VERSION}"
export CXXCPP="${CPP}"
./configure \
--prefix="${prefix}" \
--host="${arch}-apple-darwin" \
--disable-shared \
--enable-static \
--with-coreaudio=no \
--disable-gomp \
"$@" || exit
make install || exit
cat >&2 << EOF
Build succeeded! Files were installed in
$prefix
EOF
Please excuse my lazyness, i didn't cleanup the script, but it works. 
It autocompiles the lib for armv6, armv7 and i386, therefore making one big massive framework for all 3 architectures using Apple's lipo utility (which is included in xcode).
With this script placed in your sox source folder you simply have to run it.
What you finally need to do is to add the SOX.framework and two headerfiles sox.h and soxstdint.h to your Xcode Project.
If you want all files seperately, i took the liberty to adjust the script's output path to $sox-srcdir/iOS-<Version>-<arch>. Every file needed will be in those folders from withint your sox sourcedir:
- iOS-4.3-i386/
- iOS-4.3-armv6/
- iOS-4.3-armv7/
Having that done, you can do an #import "sox.h" in your project and start working on some effects.
In my next post i will be covering how to do those effects.