Windows环境下编译Android平台的libyuv

1. 说明

至于libyuv¹的用途，就不赘述了。一下是官方说明

Scale YUV to prepare content for compression, with point, bilinear or box filter.
Convert to YUV from webcam formats for compression.
Convert to RGB formats for rendering/effects.
Rotate by 90/180/270 degrees to adjust for mobile devices in portrait mode.
Optimized for SSSE3/AVX2 on x86/x64.
Optimized for Neon on Arm.
Optimized for MSA on Mips

2. 编译过程

  当然你也可以放在Android Studio上编译。这里是脱离Android studio开发环境编译，直接编译好动、静态库和头文件，可以copy给其它库用。这样比在我们自己的库中依赖编译libyuv要节省编译时间。

2.1 下载

下载源码

https://chromium.googlesource.com/libyuv/libyuv/+archive/refs/heads/master.tar.gz

  现在最新版本是 1719,可以在下载的源码中include/libyuv/version.h查看版本号

2.2 稍改CMakeLists.txt脚本

  原本我们并不需要改变CMakeLists.txt脚本，只是为了存放目录，把动、静态库放在lib目录，头文件放在include目录。如果不改变脚本，编译后，自己手动copy也是可以的。
  最重要的就是，Android studio集成cmake编译，是在打包的时候才strip掉符号表。我们脱离Android studio开发环境，直接使用Cmake编译，不管是Release版本还是Debug版本，Cmake都没有Strip掉符号表，库会比较大，所以我们在脚本里定制一个command，直接strip掉符号表。一般我们不会debug开源库。所以没有必要保留开源库的符号表，当然你也可以保留，集成到其它的JNI库通过Android studio打包的时候gradle流程依然会strip掉符号表。

# CMakeLists for libyuv
# Originally created for "roxlu build system" to compile libyuv on windows
# Run with -DTEST=ON to build unit tests

PROJECT ( YUV C CXX )	# "C" is required even for C++ projects
CMAKE_MINIMUM_REQUIRED( VERSION 2.8 )
OPTION( TEST "Built unit tests" OFF )

SET ( ly_base_dir	${PROJECT_SOURCE_DIR} )
SET ( ly_src_dir	${ly_base_dir}/source )
SET ( ly_inc_dir	${ly_base_dir}/include )
SET ( ly_tst_dir	${ly_base_dir}/unit_test )
SET ( ly_lib_name	yuv )
SET ( ly_lib_static	${ly_lib_name} )
SET ( ly_lib_shared	${ly_lib_name}_shared )

FILE ( GLOB_RECURSE	ly_source_files ${ly_src_dir}/*.cc )
LIST ( SORT			ly_source_files )

FILE ( GLOB_RECURSE	ly_unittest_sources ${ly_tst_dir}/*.cc )
LIST ( SORT			ly_unittest_sources )

INCLUDE_DIRECTORIES( BEFORE ${ly_inc_dir} )

# this creates the static library (.a)
ADD_LIBRARY				( ${ly_lib_static} STATIC ${ly_source_files} )

# this creates the shared library (.so)
ADD_LIBRARY				( ${ly_lib_shared} SHARED ${ly_source_files} )
SET_TARGET_PROPERTIES	( ${ly_lib_shared} PROPERTIES OUTPUT_NAME "${ly_lib_name}" )
SET_TARGET_PROPERTIES	( ${ly_lib_shared} PROPERTIES PREFIX "lib" )

# this creates the conversion tool
ADD_EXECUTABLE			( yuvconvert ${ly_base_dir}/util/yuvconvert.cc )
TARGET_LINK_LIBRARIES	( yuvconvert ${ly_lib_static} )


INCLUDE ( FindJPEG )
if (JPEG_FOUND)
  include_directories( ${JPEG_INCLUDE_DIR} )
  target_link_libraries( yuvconvert ${JPEG_LIBRARY} )
  add_definitions( -DHAVE_JPEG )
endif()

if(TEST)
  find_library(GTEST_LIBRARY gtest)
  if(GTEST_LIBRARY STREQUAL "GTEST_LIBRARY-NOTFOUND")
    set(GTEST_SRC_DIR /usr/src/gtest CACHE STRING "Location of gtest sources")
    if(EXISTS ${GTEST_SRC_DIR}/src/gtest-all.cc)
      message(STATUS "building gtest from sources in ${GTEST_SRC_DIR}")
      set(gtest_sources ${GTEST_SRC_DIR}/src/gtest-all.cc)
      add_library(gtest STATIC ${gtest_sources})
      include_directories(${GTEST_SRC_DIR})
      include_directories(${GTEST_SRC_DIR}/include)
      set(GTEST_LIBRARY gtest)
    else()
      message(FATAL_ERROR "TEST is set but unable to find gtest library")
    endif()
  endif()

  add_executable(libyuv_unittest ${ly_unittest_sources})
  target_link_libraries(libyuv_unittest ${ly_lib_name} ${GTEST_LIBRARY})
  find_library(PTHREAD_LIBRARY pthread)
  if(NOT PTHREAD_LIBRARY STREQUAL "PTHREAD_LIBRARY-NOTFOUND")
    target_link_libraries(libyuv_unittest pthread)
  endif()
  if (JPEG_FOUND)
    target_link_libraries(libyuv_unittest ${JPEG_LIBRARY})
  endif()

  if(NACL AND NACL_LIBC STREQUAL "newlib")
    target_link_libraries(libyuv_unittest glibc-compat)
  endif()

  find_library(GFLAGS_LIBRARY gflags)
  if(NOT GFLAGS_LIBRARY STREQUAL "GFLAGS_LIBRARY-NOTFOUND")
    target_link_libraries(libyuv_unittest gflags)
    add_definitions(-DLIBYUV_USE_GFLAGS)
  endif()
endif()

# ----------------------------------新加的内容-------------------------------------
# 为了是目录更明确，自己创建目录
if(NOT EXISTS CMAKE_INSTALL_PREFIX)
	message(WARNING "目录${CMAKE_INSTALL_PREFIX}-----not exists---------------")
	file(MAKE_DIRECTORY ${CMAKE_INSTALL_PREFIX}/lib ${CMAKE_INSTALL_PREFIX}/include)
endif()

#copy头文件文件夹,动态库和静态库文件都放在lib目录,头文件放在include目录
add_custom_command( TARGET ${ly_lib_shared} POST_BUILD
                    COMMAND ${CMAKE_COMMAND} -E copy_directory ${ly_inc_dir} ${CMAKE_INSTALL_PREFIX}/include)

# strip动态库的符号表
add_custom_command( TARGET ${ly_lib_shared} POST_BUILD
                    COMMAND "${ANDROID_TOOLCHAIN_PREFIX}strip" "--strip-unneeded" "-o" 
				"${CMAKE_INSTALL_PREFIX}/lib/lib${ly_lib_name}-strip.so" "${CMAKE_INSTALL_PREFIX}/lib/lib${ly_lib_name}.so"
                    COMMENT "strip符号表")
# ---------------------------------------------------------------------------------

# install the conversion tool, .so, .a, and all the header files
INSTALL ( PROGRAMS ${CMAKE_BINARY_DIR}/yuvconvert			DESTINATION ${CMAKE_INSTALL_PREFIX}/bin )
INSTALL ( TARGETS ${ly_lib_static}					DESTINATION ${CMAKE_INSTALL_PREFIX}/lib )
INSTALL ( TARGETS ${ly_lib_shared} LIBRARY				DESTINATION lib RUNTIME DESTINATION ${CMAKE_INSTALL_PREFIX}/bin )
INSTALL ( DIRECTORY ${PROJECT_SOURCE_DIR}/include/		DESTINATION ${CMAKE_INSTALL_PREFIX}/include )

# create the .deb and .rpm packages using cpack
INCLUDE ( CM_linux_packages.cmake )

2.3 Windows环境编译脚本bat

@echo off
cls
::==========================================================================
::本脚本用来在Windows环境使用Cmake交叉编译Android使用的libyuv库
::==========================================================================

title cmake build libyuv

chcp 65001>nul

echo.
echo.
echo.--------本脚本用来用来在Windows环境使用Cmake交叉编译Android使用的库------
echo.

echo CMD Path:%cd%
echo 当前 dir:%~dp0

rem 切换到当前目录
cd /d %~dp0

:: --------------------------------------------------------------------------
rem 临时变量
set ANDROID_NDK=F:/Android/android-ndk-r16b
set CMAKE_PATH=D:/Android/android-sdk/cmake/3.6.4111459
set NASM_PATH=D:/Progra~1/Android/nasm-2.13.03
set ANDROID_VERSION=24
set SOURCE_DIR=./libyuv-refs_heads_master
set NATIVE_BUILD_DIR=.
set INSTALL_DIR=%~dp0

set ANDROID_ARMV5_CFLAGS="-march=armv5te"
rem -mfpu=vfpv3-d16  -fexceptions -frtti
set ANDROID_ARMV7_CFLAGS="-march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -mfpu=neon"
rem -mfloat-abi=softfp -mfpu=neon -fexceptions -frtti
set ANDROID_ARMV8_CFLAGS="-march=armv8-a"   
set ANDROID_X86_CFLAGS="-march=i686 -mtune=intel -mssse3 -mfpmath=sse -m32"
set ANDROID_X86_64_CFLAGS="-march=x86-64 -msse4.2 -mpopcnt -m64 -mtune=intel"

:: --------------------------------------------------------------------------
echo.
echo.--------------------------开始build--------------------------------------
echo.

rem call:label表示调用用":"标识,以goto:eof结束的函数代码段

rem --make armeabi
call:buildLibTurboJpeg armeabi %ANDROID_ARMV5_CFLAGS%

rem --make armeabi-v7a
call:buildLibTurboJpeg armeabi-v7a %ANDROID_ARMV7_CFLAGS%

rem --make arm64-v8a
call:buildLibTurboJpeg arm64-v8a %ANDROID_ARMV8_CFLAGS%

rem --make x86
call:buildLibTurboJpeg x86 %ANDROID_X86_CFLAGS%

rem --make x86_64
call:buildLibTurboJpeg x86_64 %ANDROID_X86_64_CFLAGS%

set timeout=5
echo.倒计时 %timeout% 秒钟后自动退出
for /L %%a in (%timeout% -1 1) do ( ^
	set /p=%%a . <nul&ping -n 2 127.0.0.1>nul
)

echo.
echo.&pause&goto:eof

:: --------------------------------------------------------------------------
rem 定义函数 (%1:arch_abi,%2:cflags)
:buildLibTurboJpeg
setlocal

	echo.[func]-----------------start make [%1]---------------------------
	echo.
	
	::注意这里我们使用  %~1 引用参数是为了脱去变量赋值时的 边界 双引号""
	set ABI=%~1
	set CFLAGS=%~2
	set BINARY_DIR="%NATIVE_BUILD_DIR%/bin/%ABI%"
	set PLATFORM_VERSION=%ANDROID_VERSION%
	set LIB_OUTPUT_DIR="%INSTALL_DIR%/dist/%ABI%"
	
	rem 批处理中if else 需在一行，() 括号内容表示在"("开始的同一行
	if %ABI%==armeabi (
		echo.[func]----当前编译--^>armeabi
		goto pass
	)
	if %ABI%==armeabi-v7a (
		echo.[func]----当前编译--^>armeabi-v7a
		goto pass
	)
	if %ABI%==arm64-v8a (
		echo.[func]----当前编译--^>arm64-v8a
		goto pass
	)
	if %ABI%==x86 (
		echo.[func]----当前编译--^>x86
		goto pass
	)
	if %ABI%==x86_64 (
		echo.[func]----当前编译--^>x86_64
		goto pass
	) else (
		echo.[ERROR]----不支持的ABI---^>%ABI%
		pause>nul
		exit
	)
	
	:pass
	
	echo [func]----PLATFORM_VERSION==%ANDROID_VERSION%
	echo [func]----ABI==%ABI%
	echo [func]----CFLAGS==%CFLAGS%
	echo [func]----SOURCE_DIR==%SOURCE_DIR%
	echo [func]----BINARY_DIR==%BINARY_DIR%
	echo [func]----LIB_OUTPUT_DIR==%LIB_OUTPUT_DIR%
	echo.
	echo.
	
	if not exist %BINARY_DIR% md %BINARY_DIR%
	
	cd /d %BINARY_DIR%
	
	:: -G"MinGW Makefiles"
	:: -DCMAKE_MAKE_PROGRAM=%ANDROID_NDK%/prebuilt/windows-x86_64/bin/make.exe
	
	rem 开源库有提供cmake 		Android Gradle - Ninja ^ 
	cmake ^
		-DANDROID_ABI=%ABI% ^
		-DANDROID_PLATFORM=android-%PLATFORM_VERSION% ^
		-DCMAKE_INSTALL_PREFIX=%LIB_OUTPUT_DIR% ^
		-DCMAKE_LIBRARY_OUTPUT_DIRECTORY=%LIB_OUTPUT_DIR%/lib ^
		-DCMAKE_ARCHIVE_OUTPUT_DIRECTORY=%LIB_OUTPUT_DIR%/lib ^
		-DCMAKE_BUILD_TYPE=Release ^
		-DANDROID_NDK=%ANDROID_NDK% ^
		-DCMAKE_TOOLCHAIN_FILE=%ANDROID_NDK%/build/cmake/android.toolchain.cmake ^
		-DCMAKE_MAKE_PROGRAM=%CMAKE_PATH%/bin/ninja.exe ^
		-G"Android Gradle - Ninja" ^
		-DANDROID_ARM_NEON=TRUE ^
		-DANDROID_TOOLCHAIN=clang ^
		-DANDROID_STL=c++_static ^
		-DCMAKE_C_FLAGS="%CFLAGS% -Os -Wall -pipe -fPIC" ^
		-DANDROID_CPP_FEATURES=rtti exceptions ^
		../../%SOURCE_DIR%
		
	cmake --build ./
	rem ninja -C .
	
	cd ../../
			
	echo.[func]-----------------[%1] make end---------------------------
	echo.

endlocal
goto:eof

2.4 编译静态、动态库

  双击执行以上脚本保存的bat文件即可，等待编译完成

---

1. https://chromium.googlesource.com/libyuv/libyuv/+/refs/heads/master ↩︎