FFmpeg静态库编译小结

开篇介绍：

写这篇博客的原因是为了编译出支持 Mac App、iPad  iPhone模拟器可以调试的 ffmpeg静态库。

正题：

步骤一：编译x264静态库

脚本链接：https://github.com/kewlbear/x264-ios

下载到本地。因为代码比较老。需要做一点修改，将模拟器支持的最低版本设置为8.0

#!/bin/sh

CONFIGURE_FLAGS="--enable-static --enable-pic --disable-cli --disable-asm"

ARCHS="arm64 x86_64 i386 armv7 armv7s"

# directories
SOURCE="x264"
FAT="x264-iOS"

SCRATCH="scratch-x264"
# must be an absolute path
THIN=`pwd`/"thin-x264"

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"
		CFLAGS="-arch $ARCH"
                ASFLAGS=

		if [ "$ARCH" = "i386" -o "$ARCH" = "x86_64" ]
		then
		    PLATFORM="iPhoneSimulator"
		    CPU=
		    if [ "$ARCH" = "x86_64" ]
		    then
		    	CFLAGS="$CFLAGS -mios-simulator-version-min=8.0"
		    	HOST=
		    else
		    	CFLAGS="$CFLAGS -mios-simulator-version-min=8.0"
			HOST="--host=i386-apple-darwin"
		    fi
		else
		    PLATFORM="iPhoneOS"
		    if [ $ARCH = "arm64" ]
		    then
		        HOST="--host=aarch64-apple-darwin"
			XARCH="-arch aarch64"
		    else
		        HOST="--host=arm-apple-darwin"
			XARCH="-arch arm"
		    fi
                    CFLAGS="$CFLAGS -fembed-bitcode -mios-version-min=8.0"
                    ASFLAGS="$CFLAGS"
		fi

		XCRUN_SDK=`echo $PLATFORM | tr '[:upper:]' '[:lower:]'`
		CC="xcrun -sdk $XCRUN_SDK clang"
		if [ $PLATFORM = "iPhoneOS" ]
		then
		    export AS="$CWD/$SOURCE/tools/gas-preprocessor.pl $XARCH -- $CC"
		else
		    export -n AS
		fi
		CXXFLAGS="$CFLAGS"
		LDFLAGS="$CFLAGS"

		CC=$CC $CWD/$SOURCE/configure \
		    $CONFIGURE_FLAGS \
		    $HOST \
		    --extra-cflags="$CFLAGS" \
		    --extra-asflags="$ASFLAGS" \
		    --extra-ldflags="$LDFLAGS" \
		    --prefix="$THIN/$ARCH" || exit 1

		make -j3 install || exit 1
		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

修改完成，执行 cd 到脚本目录下 执行

./build-x264.sh arm64 armv7 armv7s x86_64 i386

脚本之行结束后，再执行

./build-x264.sh lipo

x264-iOS
 

步骤二：ffmpeg 和x264交叉编译

ffmpeg打包脚本 https://github.com/kewlbear/FFmpeg-iOS-build-script

下载到本地后，打开x264-iOSx264-iOS

 

#!/bin/sh

# directories
FF_VERSION="4.2"
#FF_VERSION="snapshot-git"
if [[ $FFMPEG_VERSION != "" ]]; then
  FF_VERSION=$FFMPEG_VERSION
fi
SOURCE="ffmpeg-$FF_VERSION"
FAT="FFmpeg-iOS"

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

# absolute path to x264 library
X264=`pwd`/x264

#FDK_AAC=`pwd`/../fdk-aac-build-script-for-iOS/fdk-aac-ios

CONFIGURE_FLAGS="--enable-cross-compile --disable-debug --disable-programs \
                 --disable-doc --enable-pic --disable-asm"

if [ "$X264" ]
then
	CONFIGURE_FLAGS="$CONFIGURE_FLAGS --enable-gpl --enable-libx264"
fi

if [ "$FDK_AAC" ]
then
	CONFIGURE_FLAGS="$CONFIGURE_FLAGS --enable-libfdk-aac --enable-nonfree"
fi

# avresample
#CONFIGURE_FLAGS="$CONFIGURE_FLAGS --enable-avresample"

ARCHS="arm64 armv7 armv7s x86_64 i386"

COMPILE="y"
LIPO="y"

DEPLOYMENT_TARGET="8.0"

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

if [ "$COMPILE" ]
then
	if [ ! `which yasm` ]
	then
		echo 'Yasm not found'
		if [ ! `which brew` ]
		then
			echo 'Homebrew not found. Trying to install...'
                        ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" \
				|| exit 1
		fi
		echo 'Trying to install Yasm...'
		brew install yasm || exit 1
	fi
	if [ ! `which gas-preprocessor.pl` ]
	then
		echo 'gas-preprocessor.pl not found. Trying to install...'
		(curl -L https://github.com/libav/gas-preprocessor/raw/master/gas-preprocessor.pl \
			-o /usr/local/bin/gas-preprocessor.pl \
			&& chmod +x /usr/local/bin/gas-preprocessor.pl) \
			|| exit 1
	fi

	if [ ! -r $SOURCE ]
	then
		echo 'FFmpeg source not found. Trying to download...'
		curl http://www.ffmpeg.org/releases/$SOURCE.tar.bz2 | tar xj \
			|| exit 1
	fi

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

		CFLAGS="-arch $ARCH"
		if [ "$ARCH" = "i386" -o "$ARCH" = "x86_64" ]
		then
		    PLATFORM="iPhoneSimulator"
		    CFLAGS="$CFLAGS -mios-simulator-version-min=$DEPLOYMENT_TARGET"
		else
		    PLATFORM="iPhoneOS"
		    CFLAGS="$CFLAGS -mios-version-min=$DEPLOYMENT_TARGET -fembed-bitcode"
		    if [ "$ARCH" = "arm64" ]
		    then
		        EXPORT="GASPP_FIX_XCODE5=1"
		    fi
		fi

		XCRUN_SDK=`echo $PLATFORM | tr '[:upper:]' '[:lower:]'`
		CC="xcrun -sdk $XCRUN_SDK clang"

		# force "configure" to use "gas-preprocessor.pl" (FFmpeg 3.3)
		if [ "$ARCH" = "arm64" ]
		then
		    AS="gas-preprocessor.pl -arch aarch64 -- $CC"
		else
		    AS="gas-preprocessor.pl -- $CC"
		fi

		CXXFLAGS="$CFLAGS"
		LDFLAGS="$CFLAGS"
		if [ "$X264" ]
		then
			CFLAGS="$CFLAGS -I$X264/include"
			LDFLAGS="$LDFLAGS -L$X264/lib"
		fi
		if [ "$FDK_AAC" ]
		then
			CFLAGS="$CFLAGS -I$FDK_AAC/include"
			LDFLAGS="$LDFLAGS -L$FDK_AAC/lib"
		fi

		TMPDIR=${TMPDIR/%\/} $CWD/$SOURCE/configure \
		    --target-os=darwin \
		    --arch=$ARCH \
		    --cc="$CC" \
		    --as="$AS" \
		    $CONFIGURE_FLAGS \
		    --extra-cflags="$CFLAGS" \
		    --extra-ldflags="$LDFLAGS" \
		    --prefix="$THIN/$ARCH" \
		|| exit 1

		make -j3 install $EXPORT || exit 1
		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
		echo lipo -create `find $THIN -name $LIB` -output $FAT/lib/$LIB 1>&2
		lipo -create `find $THIN -name $LIB` -output $FAT/lib/$LIB || exit 1
	done

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

echo Done

修改完成后保存退出,在根目录执行

./build-ffmpeg.sh arm64 armv7 armv7s x86_64 i386

编译结束后，再执行

./build-ffmpeg.sh lipo

将静态库合并。

步骤三：整理

将x264文件夹下面的.a和.h文件分别移动到FFmpeg-iOS的lib 和 include文件夹下。

结语

至此，FFmpeg-iOS中的就是完整的ffmpeg +x264解码器的静态库。因为支持了全平台。所以包比较大。如果为了减小包的体积，可以考虑移除不需要的架构。