libyuv在Android下的编译

我放了一个编译好的版本，你们可以先用起来，地址：https://www.bzblog.online/wordpress/index.php/2020/05/13/142/

libyuv是Google开源的一款处理YUV的底层库，下载地址:https://chromium.googlesource.com/libyuv/libyuv 可惜这个地址被墙了，我下载下来了，放到我服务器上了，地址：https://www.bzblog.online/public/libyuv.zip 好了接下来就是编译了，首先我们新建一个文件夹叫libyuvbuild,让后把libyuv目录拖进去，并重命名为jni(这么做事为了方便ndk-build),如图所示：

然后就是修改Android.mk了，由于libyuv默认是需要libjpeg参与编译，这个库是负责解码图片，我们在Android开发中一般是不会用到的，直接去掉就好了，最终Android.mk修改如下：

# This is the Android makefile for libyuv for NDK.
LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_CPP_EXTENSION := .cc

LOCAL_SRC_FILES := \
    source/compare.cc           \
    source/compare_common.cc    \
    source/compare_gcc.cc       \
    source/compare_mmi.cc       \
    source/compare_msa.cc       \
    source/compare_neon64.cc    \
    source/compare_neon.cc      \
    source/compare_win.cc       \
    source/convert_argb.cc      \
    source/convert.cc           \
    source/convert_from_argb.cc \
    source/convert_from.cc      \
    source/convert_to_argb.cc   \
    source/convert_to_i420.cc   \
    source/cpu_id.cc            \
    source/planar_functions.cc  \
    source/rotate_any.cc        \
    source/rotate_argb.cc       \
    source/rotate.cc            \
    source/rotate_common.cc     \
    source/rotate_gcc.cc        \
    source/rotate_mmi.cc        \
    source/rotate_msa.cc        \
    source/rotate_neon64.cc     \
    source/rotate_neon.cc       \
    source/rotate_win.cc        \
    source/row_any.cc           \
    source/row_common.cc        \
    source/row_gcc.cc           \
    source/row_mmi.cc           \
    source/row_msa.cc           \
    source/row_neon64.cc        \
    source/row_neon.cc          \
    source/row_win.cc           \
    source/scale_any.cc         \
    source/scale_argb.cc        \
    source/scale.cc             \
    source/scale_common.cc      \
    source/scale_gcc.cc         \
    source/scale_mmi.cc         \
    source/scale_msa.cc         \
    source/scale_neon64.cc      \
    source/scale_neon.cc        \
    source/scale_win.cc         \
    source/video_common.cc

common_CFLAGS := -Wall -fexceptions

LOCAL_CFLAGS += $(common_CFLAGS)
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
LOCAL_C_INCLUDES += $(LOCAL_PATH)/include
LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include

LOCAL_MODULE := libyuv_static
LOCAL_MODULE_TAGS := optional

include $(BUILD_STATIC_LIBRARY)

include $(CLEAR_VARS)

LOCAL_WHOLE_STATIC_LIBRARIES := libyuv_static
LOCAL_MODULE := libyuv


include $(BUILD_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_STATIC_LIBRARIES := libyuv_static
LOCAL_MODULE_TAGS := tests
LOCAL_CPP_EXTENSION := .cc
LOCAL_C_INCLUDES += $(LOCAL_PATH)/include
LOCAL_SRC_FILES := \
    unit_test/unit_test.cc        \
    unit_test/basictypes_test.cc  \
    unit_test/color_test.cc       \
    unit_test/compare_test.cc     \
    unit_test/convert_test.cc     \
    unit_test/cpu_test.cc         \
    unit_test/cpu_thread_test.cc  \
    unit_test/math_test.cc        \
    unit_test/planar_test.cc      \
    unit_test/rotate_argb_test.cc \
    unit_test/rotate_test.cc      \
    unit_test/scale_argb_test.cc  \
    unit_test/scale_test.cc       \
    unit_test/video_common_test.cc

LOCAL_MODULE := libyuv_unittest
include $(BUILD_NATIVE_TEST)

再然后就是添加Application.mk支持多种CPU架构，文件内容如下：

NDK_TOOLCHAIN_VERSION := clang
APP_ABI := armeabi-v7a arm64-v8a x86 x86_64
APP_CPPFLAGS := -std=c++11 -frtti -fexceptions
APP_PLATFORM := android-11
APP_STL := gnustl_static
#APP_CFLAGS+=-DDLIB_NO_GUI_SUPPORT=on
#APP_CFLAGS+=-DDLIB_PNG_SUPPORT=off
APP_CFLAGS+=-DDLIB_JPEG_SUPPORT=on
APP_CFLAGS+=-DDLIB_JPEG_STATIC=on

最后就是cd 到libyuvbuild目录然后执行ndk-build就好了，默认会编译静态和动态库（需要注意ndk-build的环境变量是添加过来），编译过的结果如下：

libyuv的封装：https://www.bzblog.online/wordpress/index.php/2020/05/25/androidlibyuv/