MTK 多帧算法集成实现流程-技术圈

和你一起终身学 习，这里是程序员Android

经典好文推荐，通过阅读本文，您将收获以下知识点:

一、选择feature和配置feature table
二、挂载算法
三、自定义metadata
四、APP调用算法
五、结语

一、选择feature和配置feature table

1.1 选择feature

多帧降噪算法(MFNR)是一种很常见的多帧算法，在MTK已预置的feature中有MTK_FEATURE_MFNR和TP_FEATURE_MFNR。因此，我们可以对号入座，不用再额外添加feature。这里我们是第三方算法，所以我们选择TP_FEATURE_MFNR。

1.2 配置feature table

确定了feature为TP_FEATURE_MFNR后，我们还需要将其添加到feature table中：

    diff --git a/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/mtk_scenario_mgr.cpp b/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/mtk_scenario_mgr.cpp
index f14ff8a6e2..38365e0602 100755
--- a/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/mtk_scenario_mgr.cpp
+++ b/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/mtk_scenario_mgr.cpp
@@ -106,6 +106,7 @@ using namespace NSCam::v3::pipeline::policy::scenariomgr;
#define MTK_FEATURE_COMBINATION_TP_VSDOF_MFNR     (MTK_FEATURE_MFNR    | MTK_FEATURE_NR| MTK_FEATURE_ABF| MTK_FEATURE_CZ| MTK_FEATURE_DRE| MTK_FEATURE_HFG| MTK_FEATURE_DCE | MTK_FEATURE_FB| TP_FEATURE_VSDOF| TP_FEATURE_WATERMARK)
#define MTK_FEATURE_COMBINATION_TP_FUSION         (NO_FEATURE_NORMAL   | MTK_FEATURE_NR| MTK_FEATURE_ABF| MTK_FEATURE_CZ| MTK_FEATURE_DRE| MTK_FEATURE_HFG| MTK_FEATURE_DCE | MTK_FEATURE_FB| TP_FEATURE_FUSION| TP_FEATURE_WATERMARK)
#define MTK_FEATURE_COMBINATION_TP_PUREBOKEH      (NO_FEATURE_NORMAL   | MTK_FEATURE_NR| MTK_FEATURE_ABF| MTK_FEATURE_CZ| MTK_FEATURE_DRE| MTK_FEATURE_HFG| MTK_FEATURE_DCE | MTK_FEATURE_FB| TP_FEATURE_PUREBOKEH| TP_FEATURE_WATERMARK)
+#define MTK_FEATURE_COMBINATION_TP_MFNR           (TP_FEATURE_MFNR     | MTK_FEATURE_NR| MTK_FEATURE_ABF| MTK_FEATURE_CZ| MTK_FEATURE_DRE| MTK_FEATURE_HFG| MTK_FEATURE_DCE | MTK_FEATURE_FB| MTK_FEATURE_MFNR)

// streaming feature combination (TODO: it should be refined by streaming scenario feature)
#define MTK_FEATURE_COMBINATION_VIDEO_NORMAL     (MTK_FEATURE_FB|TP_FEATURE_FB|TP_FEATURE_WATERMARK)
@@ -136,6 +137,7 @@ const std::vector<std::unordered_map<int32_t, ScenarioFeatures>>  gMtkScenarioFe
ADD_CAMERA_FEATURE_SET(TP_FEATURE_HDR,       MTK_FEATURE_COMBINATION_HDR)
ADD_CAMERA_FEATURE_SET(MTK_FEATURE_AINR,     MTK_FEATURE_COMBINATION_AINR)
ADD_CAMERA_FEATURE_SET(MTK_FEATURE_MFNR,     MTK_FEATURE_COMBINATION_MFNR)
+        ADD_CAMERA_FEATURE_SET(TP_FEATURE_MFNR,      MTK_FEATURE_COMBINATION_TP_MFNR)
ADD_CAMERA_FEATURE_SET(MTK_FEATURE_REMOSAIC, MTK_FEATURE_COMBINATION_REMOSAIC)
ADD_CAMERA_FEATURE_SET(NO_FEATURE_NORMAL,    MTK_FEATURE_COMBINATION_SINGLE)
         CAMERA_SCENARIO_END

注意：

MTK在Android Q（10.0）及更高版本上优化了scenario配置表的客制化，Android Q及更高版本，feature需要在：
vendor/mediatek/proprietary/custom/[platform]/hal/camera/camera_custom_feature_table.cpp中配置，[platform]是诸如mt6580，mt6763之类的。

二、挂载算法

2.1 为算法选择plugin

MTK HAL3在vendor/mediatek/proprietary/hardware/mtkcam3/include/mtkcam3/3rdparty/plugin/PipelinePluginType.h 中将三方算法的挂载点大致分为以下几类：

BokehPlugin：Bokeh算法挂载点，双摄景深算法的虚化部分。
DepthPlugin：Depth算法挂载点，双摄景深算法的计算深度部分。
FusionPlugin：Depth和Bokeh放在1个算法中，即合并的双摄景深算法挂载点。
JoinPlugin：Streaming相关算法挂载点，预览算法都挂载在这里。
MultiFramePlugin：多帧算法挂载点，包括YUV与RAW，例如MFNR/HDR
RawPlugin：RAW算法挂载点，例如remosaic
YuvPlugin：Yuv单帧算法挂载点，例如美颜、广角镜头畸变校正等。

对号入座，为要集成的算法选择相应的plugin。这里是多帧算法，只能选择MultiFramePlugin。并且，一般情况下多帧算法只用于拍照，不用于预览。

2.2 添加全局宏控

为了能控制某个项目是否集成此算法，我们在device/mediateksample/[platform]/ProjectConfig.mk中添加一个宏，用于控制新接入算法的编译：

    QXT_MFNR_SUPPORT = yes

当某个项目不需要这个算法时，将device/mediateksample/[platform]/ProjectConfig.mk的QXT_MFNR_SUPPORT的值设为 no 就可以了。

2.3 编写算法集成文件

参照vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/mfnr/MFNRImpl.cpp中实现MFNR拍照。目录结构如下：
vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/customer/cp_tp_mfnr/
├── Android.mk
├── include
│ └── mf_processor.h
├── lib
│ ├── arm64-v8a
│ │ └── libmultiframe.so
│ └── armeabi-v7a
│ └── libmultiframe.so
└── MFNRImpl.cpp

文件说明：

Android.mk中配置算法库、头文件、集成的源代码MFNRImpl.cpp文件，将它们编译成库libmtkcam.plugin.tp_mfnr，供libmtkcam_3rdparty.customer依赖调用。
libmultiframe.so实现了将连续4帧图像缩小，并拼接成一张图的功能，libmultiframe.so用来模拟需要接入的第三方多帧算法库。mf_processor.h是头文件。
MFNRImpl.cpp是集成的源代码CPP文件。

2.3.1 mtkcam3/3rdparty/customer/cp_tp_mfnr/Android.mk

    ifeq ($(QXT_MFNR_SUPPORT),yes)
LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)
LOCAL_MODULE := libmultiframe
LOCAL_SRC_FILES_32 := lib/armeabi-v7a/libmultiframe.so
LOCAL_SRC_FILES_64 := lib/arm64-v8a/libmultiframe.so
LOCAL_MODULE_TAGS := optional
LOCAL_MODULE_CLASS := SHARED_LIBRARIES
LOCAL_MODULE_SUFFIX := .so
LOCAL_PROPRIETARY_MODULE := true
LOCAL_MULTILIB := both
include $(BUILD_PREBUILT)

################################################################################
#
################################################################################
include $(CLEAR_VARS)

#-----------------------------------------------------------
-include $(TOP)/$(MTK_PATH_SOURCE)/hardware/mtkcam/mtkcam.mk

#-----------------------------------------------------------
LOCAL_SRC_FILES += MFNRImpl.cpp

#-----------------------------------------------------------
LOCAL_C_INCLUDES += $(MTKCAM_C_INCLUDES)
LOCAL_C_INCLUDES += $(TOP)/$(MTK_PATH_SOURCE)/hardware/mtkcam3/include $(MTK_PATH_SOURCE)/hardware/mtkcam/include
LOCAL_C_INCLUDES += $(TOP)/$(MTK_PATH_COMMON)/hal/inc
LOCAL_C_INCLUDES += $(TOP)/$(MTK_PATH_CUSTOM_PLATFORM)/hal/inc
LOCAL_C_INCLUDES += $(TOP)/external/libyuv/files/include/
LOCAL_C_INCLUDES += $(TOP)/$(MTK_PATH_SOURCE)/hardware/mtkcam3/3rdparty/customer/cp_tp_mfnr/include
#
LOCAL_C_INCLUDES += system/media/camera/include

#-----------------------------------------------------------
LOCAL_CFLAGS += $(MTKCAM_CFLAGS)
#

#-----------------------------------------------------------
LOCAL_STATIC_LIBRARIES +=
#
LOCAL_WHOLE_STATIC_LIBRARIES +=

#-----------------------------------------------------------
LOCAL_SHARED_LIBRARIES += liblog
LOCAL_SHARED_LIBRARIES += libutils
LOCAL_SHARED_LIBRARIES += libcutils
LOCAL_SHARED_LIBRARIES += libmtkcam_modulehelper
LOCAL_SHARED_LIBRARIES += libmtkcam_stdutils
LOCAL_SHARED_LIBRARIES += libmtkcam_pipeline
LOCAL_SHARED_LIBRARIES += libmtkcam_metadata
LOCAL_SHARED_LIBRARIES += libmtkcam_metastore
LOCAL_SHARED_LIBRARIES += libmtkcam_streamutils
LOCAL_SHARED_LIBRARIES += libmtkcam_imgbuf
LOCAL_SHARED_LIBRARIES += libmtkcam_exif
#LOCAL_SHARED_LIBRARIES += libmtkcam_3rdparty

#-----------------------------------------------------------
LOCAL_HEADER_LIBRARIES := libutils_headers liblog_headers libhardware_headers

#-----------------------------------------------------------
LOCAL_MODULE := libmtkcam.plugin.tp_mfnr
LOCAL_PROPRIETARY_MODULE := true
LOCAL_MODULE_OWNER := mtk
LOCAL_MODULE_TAGS := optional
include $(MTK_STATIC_LIBRARY)

################################################################################
#
################################################################################
include $(call all-makefiles-under,$(LOCAL_PATH))
endif

2.3.2 mtkcam3/3rdparty/customer/cp_tp_mfnr/include/mf_processor.h

    #ifndef QXT_MULTI_FRAME_H
#define QXT_MULTI_FRAME_H

class MFProcessor {

public:
virtual ~MFProcessor() {}

virtual void setFrameCount(int num) = 0;

virtual void setParams() = 0;

virtual void addFrame(unsigned char *src, int srcWidth, int srcHeight) = 0;

virtual void addFrame(unsigned char *srcY, unsigned char *srcU, unsigned char *srcV,
int srcWidth, int srcHeight) = 0;

virtual void scale(unsigned char *src, int srcWidth, int srcHeight,
unsigned char *dst, int dstWidth, int dstHeight) = 0;

virtual void process(unsigned char *output, int outputWidth, int outputHeight) = 0;

virtual void process(unsigned char *outputY, unsigned char *outputU, unsigned char *outputV,
int outputWidth, int outputHeight) = 0;

static MFProcessor* createInstance(int width, int height);
};

#endif //QXT_MULTI_FRAME_H

头文件中的接口函数介绍：

setFrameCount：没有实际作用，用于模拟设置第三方多帧算法的帧数。因为部分第三方多帧算法在不同场景下需要的帧数可能是不同的。
setParams：也没有实际作用，用于模拟设置第三方多帧算法所需的参数。
addFrame：用于添加一帧图像数据，用于模拟第三方多帧算法添加图像数据。
process：将前面添加的4帧图像数据，缩小并拼接成一张原大小的图。
createInstance：创建接口类对象。

为了方便有兴趣的童鞋们，实现代码mf_processor_impl.cpp也一并贴上：

    #include <libyuv/scale.h>
#include <cstring>
#include "mf_processor.h"

using namespace std;
using namespace libyuv;

class MFProcessorImpl : public MFProcessor {
private:
int frameCount = 4;
int currentIndex = 0;
unsigned char *dstBuf = nullptr;
unsigned char *tmpBuf = nullptr;

public:
MFProcessorImpl();

MFProcessorImpl(int width, int height);

~MFProcessorImpl() override;

void setFrameCount(int num) override;

void setParams() override;

void addFrame(unsigned char *src, int srcWidth, int srcHeight) override;

void addFrame(unsigned char *srcY, unsigned char *srcU, unsigned char *srcV,
int srcWidth, int srcHeight) override;

void scale(unsigned char *src, int srcWidth, int srcHeight,
unsigned char *dst, int dstWidth, int dstHeight) override;

void process(unsigned char *output, int outputWidth, int outputHeight) override;

void process(unsigned char *outputY, unsigned char *outputU, unsigned char *outputV,
int outputWidth, int outputHeight) override;

static MFProcessor *createInstance(int width, int height);
};

MFProcessorImpl::MFProcessorImpl() = default;

MFProcessorImpl::MFProcessorImpl(int width, int height) {
if (dstBuf == nullptr) {
        dstBuf = new unsigned char[width * height * 3 / 2];
}
if (tmpBuf == nullptr) {
        tmpBuf = new unsigned char[width / 2 * height / 2 * 3 / 2];
}
}

MFProcessorImpl::~MFProcessorImpl() {
if (dstBuf != nullptr) {
delete[] dstBuf;
}

if (tmpBuf != nullptr) {
delete[] tmpBuf;
}
}

void MFProcessorImpl::setFrameCount(int num) {
    frameCount = num;
}

void MFProcessorImpl::setParams() {

}

void MFProcessorImpl::addFrame(unsigned char *src, int srcWidth, int srcHeight) {
int srcYCount = srcWidth * srcHeight;
int srcUVCount = srcWidth * srcHeight / 4;
int tmpWidth = srcWidth >> 1;
int tmpHeight = srcHeight >> 1;
int tmpYCount = tmpWidth * tmpHeight;
int tmpUVCount = tmpWidth * tmpHeight / 4;
//scale
I420Scale(src, srcWidth,
              src + srcYCount, srcWidth >> 1,
              src + srcYCount + srcUVCount, srcWidth >> 1,
              srcWidth, srcHeight,
              tmpBuf, tmpWidth,
              tmpBuf + tmpYCount, tmpWidth >> 1,
              tmpBuf + tmpYCount + tmpUVCount, tmpWidth >> 1,
              tmpWidth, tmpHeight,
              kFilterNone);

//merge
unsigned char *pDstY;
unsigned char *pTmpY;
for (int i = 0; i < tmpHeight; i++) {
        pTmpY = tmpBuf + i * tmpWidth;
if (currentIndex == 0) {
            pDstY = dstBuf + i * srcWidth;
} else if (currentIndex == 1) {
            pDstY = dstBuf + i * srcWidth + tmpWidth;
} else if (currentIndex == 2) {
            pDstY = dstBuf + (i + tmpHeight) * srcWidth;
} else {
            pDstY = dstBuf + (i + tmpHeight) * srcWidth + tmpWidth;
}
memcpy(pDstY, pTmpY, tmpWidth);
}

int uvHeight = tmpHeight / 2;
int uvWidth = tmpWidth / 2;
unsigned char *pDstU;
unsigned char *pDstV;
unsigned char *pTmpU;
unsigned char *pTmpV;
for (int i = 0; i < uvHeight; i++) {
        pTmpU = tmpBuf + tmpYCount + uvWidth * i;
        pTmpV = tmpBuf + tmpYCount + tmpUVCount + uvWidth * i;
if (currentIndex == 0) {
            pDstU = dstBuf + srcYCount + i * tmpWidth;
            pDstV = dstBuf + srcYCount + srcUVCount + i * tmpWidth;
} else if (currentIndex == 1) {
            pDstU = dstBuf + srcYCount + i * tmpWidth + uvWidth;
            pDstV = dstBuf + srcYCount + srcUVCount + i * tmpWidth + uvWidth;
} else if (currentIndex == 2) {
            pDstU = dstBuf + srcYCount + (i + uvHeight) * tmpWidth;
            pDstV = dstBuf + srcYCount + srcUVCount + (i + uvHeight) * tmpWidth;
} else {
            pDstU = dstBuf + srcYCount + (i + uvHeight) * tmpWidth + uvWidth;
            pDstV = dstBuf + srcYCount + srcUVCount + (i + uvHeight) * tmpWidth + uvWidth;
}
memcpy(pDstU, pTmpU, uvWidth);
memcpy(pDstV, pTmpV, uvWidth);
}
if (currentIndex < frameCount) currentIndex++;
}

void MFProcessorImpl::addFrame(unsigned char *srcY, unsigned char *srcU, unsigned char *srcV,
int srcWidth, int srcHeight) {
int srcYCount = srcWidth * srcHeight;
int srcUVCount = srcWidth * srcHeight / 4;
int tmpWidth = srcWidth >> 1;
int tmpHeight = srcHeight >> 1;
int tmpYCount = tmpWidth * tmpHeight;
int tmpUVCount = tmpWidth * tmpHeight / 4;
//scale
I420Scale(srcY, srcWidth,
              srcU, srcWidth >> 1,
              srcV, srcWidth >> 1,
              srcWidth, srcHeight,
              tmpBuf, tmpWidth,
              tmpBuf + tmpYCount, tmpWidth >> 1,
              tmpBuf + tmpYCount + tmpUVCount, tmpWidth >> 1,
              tmpWidth, tmpHeight,
              kFilterNone);

//merge
unsigned char *pDstY;
unsigned char *pTmpY;
for (int i = 0; i < tmpHeight; i++) {
        pTmpY = tmpBuf + i * tmpWidth;
if (currentIndex == 0) {
            pDstY = dstBuf + i * srcWidth;
} else if (currentIndex == 1) {
            pDstY = dstBuf + i * srcWidth + tmpWidth;
} else if (currentIndex == 2) {
            pDstY = dstBuf + (i + tmpHeight) * srcWidth;
} else {
            pDstY = dstBuf + (i + tmpHeight) * srcWidth + tmpWidth;
}
memcpy(pDstY, pTmpY, tmpWidth);
}

int uvHeight = tmpHeight / 2;
int uvWidth = tmpWidth / 2;
unsigned char *pDstU;
unsigned char *pDstV;
unsigned char *pTmpU;
unsigned char *pTmpV;
for (int i = 0; i < uvHeight; i++) {
        pTmpU = tmpBuf + tmpYCount + uvWidth * i;
        pTmpV = tmpBuf + tmpYCount + tmpUVCount + uvWidth * i;
if (currentIndex == 0) {
            pDstU = dstBuf + srcYCount + i * tmpWidth;
            pDstV = dstBuf + srcYCount + srcUVCount + i * tmpWidth;
} else if (currentIndex == 1) {
            pDstU = dstBuf + srcYCount + i * tmpWidth + uvWidth;
            pDstV = dstBuf + srcYCount + srcUVCount + i * tmpWidth + uvWidth;
} else if (currentIndex == 2) {
            pDstU = dstBuf + srcYCount + (i + uvHeight) * tmpWidth;
            pDstV = dstBuf + srcYCount + srcUVCount + (i + uvHeight) * tmpWidth;
} else {
            pDstU = dstBuf + srcYCount + (i + uvHeight) * tmpWidth + uvWidth;
            pDstV = dstBuf + srcYCount + srcUVCount + (i + uvHeight) * tmpWidth + uvWidth;
}
memcpy(pDstU, pTmpU, uvWidth);
memcpy(pDstV, pTmpV, uvWidth);
}
if (currentIndex < frameCount) currentIndex++;
}

void MFProcessorImpl::scale(unsigned char *src, int srcWidth, int srcHeight,
unsigned char *dst, int dstWidth, int dstHeight) {
I420Scale(src, srcWidth,//Y
              src + srcWidth * srcHeight, srcWidth >> 1,//U
              src + srcWidth * srcHeight * 5 / 4, srcWidth >> 1,//V
              srcWidth, srcHeight,
              dst, dstWidth,//Y
              dst + dstWidth * dstHeight, dstWidth >> 1,//U
              dst + dstWidth * dstHeight * 5 / 4, dstWidth >> 1,//V
              dstWidth, dstHeight,
              kFilterNone);
}

void MFProcessorImpl::process(unsigned char *output, int outputWidth, int outputHeight) {
memcpy(output, dstBuf, outputWidth * outputHeight * 3 / 2);
    currentIndex = 0;
}

void MFProcessorImpl::process(unsigned char *outputY, unsigned char *outputU, unsigned char *outputV,
int outputWidth, int outputHeight) {
int yCount = outputWidth * outputHeight;
int uvCount = yCount / 4;
memcpy(outputY, dstBuf, yCount);
memcpy(outputU, dstBuf + yCount, uvCount);
memcpy(outputV, dstBuf + yCount + uvCount, uvCount);
    currentIndex = 0;
}

MFProcessor* MFProcessor::createInstance(int width, int height) {
return new MFProcessorImpl(width, height);
}

2.3.3 mtkcam3/3rdparty/customer/cp_tp_mfnr/MFNRImpl.cpp

    #ifdef LOG_TAG
#undef LOG_TAG
#endif // LOG_TAG
#define LOG_TAG "MFNRProvider"
static const char *__CALLERNAME__ = LOG_TAG;

//
#include <mtkcam/utils/std/Log.h>
//
#include <stdlib.h>
#include <utils/Errors.h>
#include <utils/List.h>
#include <utils/RefBase.h>
#include <sstream>
#include <unordered_map> // std::unordered_map
//
#include <mtkcam/utils/metadata/client/mtk_metadata_tag.h>
#include <mtkcam/utils/metadata/hal/mtk_platform_metadata_tag.h>
//zHDR
#include <mtkcam/utils/hw/HwInfoHelper.h> // NSCamHw::HwInfoHelper
#include <mtkcam3/feature/utils/FeatureProfileHelper.h> //ProfileParam
#include <mtkcam/drv/IHalSensor.h>
//
#include <mtkcam/utils/imgbuf/IIonImageBufferHeap.h>
//
#include <mtkcam/utils/std/Format.h>
#include <mtkcam/utils/std/Time.h>
//
#include <mtkcam3/pipeline/hwnode/NodeId.h>
//
#include <mtkcam/utils/metastore/IMetadataProvider.h>
#include <mtkcam/utils/metastore/ITemplateRequest.h>
#include <mtkcam/utils/metastore/IMetadataProvider.h>
#include <mtkcam3/3rdparty/plugin/PipelinePlugin.h>
#include <mtkcam3/3rdparty/plugin/PipelinePluginType.h>
//
#include <isp_tuning/isp_tuning.h>  //EIspProfile_T, EOperMode_*

//
#include <custom_metadata/custom_metadata_tag.h>

//
#include <libyuv.h>
#include <mf_processor.h>

using namespace NSCam;
using namespace android;
using namespace std;
using namespace NSCam::NSPipelinePlugin;
using namespace NSIspTuning;
/******************************************************************************
 *
 ******************************************************************************/
#define MY_LOGV(fmt, arg...)        CAM_LOGV("(%d)[%s] " fmt, ::gettid(), __FUNCTION__, ##arg)
#define MY_LOGD(fmt, arg...)        CAM_LOGD("(%d)[%s] " fmt, ::gettid(), __FUNCTION__, ##arg)
#define MY_LOGI(fmt, arg...)        CAM_LOGI("(%d)[%s] " fmt, ::gettid(), __FUNCTION__, ##arg)
#define MY_LOGW(fmt, arg...)        CAM_LOGW("(%d)[%s] " fmt, ::gettid(), __FUNCTION__, ##arg)
#define MY_LOGE(fmt, arg...)        CAM_LOGE("(%d)[%s] " fmt, ::gettid(), __FUNCTION__, ##arg)
//
#define MY_LOGV_IF(cond, ...)       do { if ( (cond) ) { MY_LOGV(__VA_ARGS__); } }while(0)
#define MY_LOGD_IF(cond, ...)       do { if ( (cond) ) { MY_LOGD(__VA_ARGS__); } }while(0)
#define MY_LOGI_IF(cond, ...)       do { if ( (cond) ) { MY_LOGI(__VA_ARGS__); } }while(0)
#define MY_LOGW_IF(cond, ...)       do { if ( (cond) ) { MY_LOGW(__VA_ARGS__); } }while(0)
#define MY_LOGE_IF(cond, ...)       do { if ( (cond) ) { MY_LOGE(__VA_ARGS__); } }while(0)
//
#define ASSERT(cond, msg)           do { if (!(cond)) { printf("Failed: %s\n", msg); return; } }while(0)

#define __DEBUG // enable debug

#ifdef __DEBUG
#include <memory>
#define FUNCTION_SCOPE \
auto __scope_logger__ = [](char const* f)->std::shared_ptr<const char>{ \
    CAM_LOGD("(%d)[%s] + ", ::gettid(), f); \
    return std::shared_ptr<const char>(f, [](char const* p){CAM_LOGD("(%d)[%s] -", ::gettid(), p);}); \
}(__FUNCTION__)
#else
#define FUNCTION_SCOPE
#endif

template <typename T>
inline MBOOL
tryGetMetadata(
    IMetadata* pMetadata,
    MUINT32 const tag,
    T & rVal
)
{
if (pMetadata == NULL) {
MY_LOGW("pMetadata == NULL");
return MFALSE;
}

    IMetadata::IEntry entry = pMetadata->entryFor(tag);
if (!entry.isEmpty()) {
        rVal = entry.itemAt(0, Type2Type<T>());
return MTRUE;
}
return MFALSE;
}

#define MFNR_FRAME_COUNT 4
/******************************************************************************
*
******************************************************************************/
class MFNRProviderImpl : public MultiFramePlugin::IProvider {
typedef MultiFramePlugin::Property Property;
typedef MultiFramePlugin::Selection Selection;
typedef MultiFramePlugin::Request::Ptr RequestPtr;
typedef MultiFramePlugin::RequestCallback::Ptr RequestCallbackPtr;

public:

virtual void set(MINT32 iOpenId, MINT32 iOpenId2) {
MY_LOGD("set openId:%d openId2:%d", iOpenId, iOpenId2);
        mOpenId = iOpenId;
}

virtual const Property& property() {
        FUNCTION_SCOPE;
static Property prop;
static bool inited;

if (!inited) {
            prop.mName              = "TP_MFNR";
            prop.mFeatures          = TP_FEATURE_MFNR;
            prop.mThumbnailTiming   = eTiming_P2;
            prop.mPriority          = ePriority_Highest;
            prop.mZsdBufferMaxNum   = 8; // maximum frames requirement
            prop.mNeedRrzoBuffer    = MTRUE; // rrzo requirement for BSS
            inited                  = MTRUE;
}
return prop;
};

virtual MERROR negotiate(Selection& sel) {
        FUNCTION_SCOPE;

        IMetadata* appInMeta = sel.mIMetadataApp.getControl().get();
        tryGetMetadata<MINT32>(appInMeta, QXT_FEATURE_MFNR, mEnable);
MY_LOGD("mEnable: %d", mEnable);
if (!mEnable) {
MY_LOGD("Force off TP_MFNR shot");
return BAD_VALUE;
}

        sel.mRequestCount = MFNR_FRAME_COUNT;

MY_LOGD("mRequestCount=%d", sel.mRequestCount);
        sel.mIBufferFull
.setRequired(MTRUE)
.addAcceptedFormat(eImgFmt_I420) // I420 first
.addAcceptedFormat(eImgFmt_YV12)
.addAcceptedFormat(eImgFmt_NV21)
.addAcceptedFormat(eImgFmt_NV12)
.addAcceptedSize(eImgSize_Full);
//sel.mIBufferSpecified.setRequired(MTRUE).setAlignment(16, 16);
        sel.mIMetadataDynamic.setRequired(MTRUE);
        sel.mIMetadataApp.setRequired(MTRUE);
        sel.mIMetadataHal.setRequired(MTRUE);
if (sel.mRequestIndex == 0) {
            sel.mOBufferFull
.setRequired(MTRUE)
.addAcceptedFormat(eImgFmt_I420) // I420 first
.addAcceptedFormat(eImgFmt_YV12)
.addAcceptedFormat(eImgFmt_NV21)
.addAcceptedFormat(eImgFmt_NV12)
.addAcceptedSize(eImgSize_Full);
            sel.mOMetadataApp.setRequired(MTRUE);
            sel.mOMetadataHal.setRequired(MTRUE);
} else {
            sel.mOBufferFull.setRequired(MFALSE);
            sel.mOMetadataApp.setRequired(MFALSE);
            sel.mOMetadataHal.setRequired(MFALSE);
}

return OK;
};

virtual void init() {
        FUNCTION_SCOPE;
        mDump = property_get_bool("vendor.debug.camera.mfnr.dump", 0);
//nothing to do for MFNR
};

virtual MERROR process(RequestPtr pRequest, RequestCallbackPtr pCallback) {
        FUNCTION_SCOPE;
        MERROR ret = 0;
// restore callback function for abort API
if (pCallback != nullptr) {
            m_callbackprt = pCallback;
}
//maybe need to keep a copy in member<sp>
        IMetadata* pAppMeta = pRequest->mIMetadataApp->acquire();
        IMetadata* pHalMeta = pRequest->mIMetadataHal->acquire();
        IMetadata* pHalMetaDynamic = pRequest->mIMetadataDynamic->acquire();
        MINT32 processUniqueKey = 0;
        IImageBuffer* pInImgBuffer = NULL;
uint32_t width = 0;
uint32_t height = 0;
if (!IMetadata::getEntry<MINT32>(pHalMeta, MTK_PIPELINE_UNIQUE_KEY, processUniqueKey)) {
MY_LOGE("cannot get unique about MFNR capture");
return BAD_VALUE;
}

if (pRequest->mIBufferFull != nullptr) {
            pInImgBuffer = pRequest->mIBufferFull->acquire();
            width = pInImgBuffer->getImgSize().w;
            height = pInImgBuffer->getImgSize().h;
MY_LOGD("[IN] Full image VA: 0x%p, Size(%dx%d), Format: %s",
                pInImgBuffer->getBufVA(0), width, height, format2String(pInImgBuffer->getImgFormat()));
if (mDump) {
char path[256];
snprintf(path, sizeof(path), "/data/vendor/camera_dump/mfnr_capture_in_%d_%dx%d.%s",
                        pRequest->mRequestIndex, width, height, format2String(pInImgBuffer->getImgFormat()));
                pInImgBuffer->saveToFile(path);
}
}
if (pRequest->mIBufferSpecified != nullptr) {
            IImageBuffer* pImgBuffer = pRequest->mIBufferSpecified->acquire();
MY_LOGD("[IN] Specified image VA: 0x%p, Size(%dx%d)", pImgBuffer->getBufVA(0), pImgBuffer->getImgSize().w, pImgBuffer->getImgSize().h);
}
if (pRequest->mOBufferFull != nullptr) {
            mOutImgBuffer = pRequest->mOBufferFull->acquire();
MY_LOGD("[OUT] Full image VA: 0x%p, Size(%dx%d)", mOutImgBuffer->getBufVA(0), mOutImgBuffer->getImgSize().w, mOutImgBuffer->getImgSize().h);
}
if (pRequest->mIMetadataDynamic != nullptr) {
            IMetadata *meta = pRequest->mIMetadataDynamic->acquire();
if (meta != NULL)
MY_LOGD("[IN] Dynamic metadata count: ", meta->count());
else
MY_LOGD("[IN] Dynamic metadata Empty");
}

MY_LOGD("frame:%d/%d, width:%d, height:%d", pRequest->mRequestIndex, pRequest->mRequestCount, width, height);

if (pInImgBuffer != NULL && mOutImgBuffer != NULL) {
uint32_t yLength = pInImgBuffer->getBufSizeInBytes(0);
uint32_t uLength = pInImgBuffer->getBufSizeInBytes(1);
uint32_t vLength = pInImgBuffer->getBufSizeInBytes(2);
uint32_t yuvLength = yLength + uLength + vLength;

if (pRequest->mRequestIndex == 0) {//First frame
//When width or height changed, recreate multiFrame
if (mLatestWidth != width || mLatestHeight != height) {
if (mMFProcessor != NULL) {
delete mMFProcessor;
                        mMFProcessor = NULL;
}
                    mLatestWidth = width;
                    mLatestHeight = height;
}
if (mMFProcessor == NULL) {
MY_LOGD("create mMFProcessor %dx%d", mLatestWidth, mLatestHeight);
                    mMFProcessor = MFProcessor::createInstance(mLatestWidth, mLatestHeight);
                    mMFProcessor->setFrameCount(pRequest->mRequestCount);
}
}

            mMFProcessor->addFrame((uint8_t *)pInImgBuffer->getBufVA(0),
(uint8_t *)pInImgBuffer->getBufVA(1),
(uint8_t *)pInImgBuffer->getBufVA(2),
                                  mLatestWidth, mLatestHeight);

if (pRequest->mRequestIndex == pRequest->mRequestCount - 1) {//Last frame
if (mMFProcessor != NULL) {
                    mMFProcessor->process((uint8_t *)mOutImgBuffer->getBufVA(0),
(uint8_t *)mOutImgBuffer->getBufVA(1),
(uint8_t *)mOutImgBuffer->getBufVA(2),
                                         mLatestWidth, mLatestHeight);
if (mDump) {
char path[256];
snprintf(path, sizeof(path), "/data/vendor/camera_dump/mfnr_capture_out_%d_%dx%d.%s",
                            pRequest->mRequestIndex, mOutImgBuffer->getImgSize().w, mOutImgBuffer->getImgSize().h,
format2String(mOutImgBuffer->getImgFormat()));
                        mOutImgBuffer->saveToFile(path);
}
} else {
memcpy((uint8_t *)mOutImgBuffer->getBufVA(0),
(uint8_t *)pInImgBuffer->getBufVA(0),
                           pInImgBuffer->getBufSizeInBytes(0));
memcpy((uint8_t *)mOutImgBuffer->getBufVA(1),
(uint8_t *)pInImgBuffer->getBufVA(1),
                           pInImgBuffer->getBufSizeInBytes(1));
memcpy((uint8_t *)mOutImgBuffer->getBufVA(2),
(uint8_t *)pInImgBuffer->getBufVA(2),
                           pInImgBuffer->getBufSizeInBytes(2));
}
                mOutImgBuffer = NULL;
}
}

if (pRequest->mIBufferFull != nullptr) {
            pRequest->mIBufferFull->release();
}
if (pRequest->mIBufferSpecified != nullptr) {
            pRequest->mIBufferSpecified->release();
}
if (pRequest->mOBufferFull != nullptr) {
            pRequest->mOBufferFull->release();
}
if (pRequest->mIMetadataDynamic != nullptr) {
            pRequest->mIMetadataDynamic->release();
}

        mvRequests.push_back(pRequest);
MY_LOGD("collected request(%d/%d)", pRequest->mRequestIndex, pRequest->mRequestCount);
if (pRequest->mRequestIndex == pRequest->mRequestCount - 1) {
for (auto req : mvRequests) {
MY_LOGD("callback request(%d/%d) %p", req->mRequestIndex, req->mRequestCount, pCallback.get());
if (pCallback != nullptr) {
                    pCallback->onCompleted(req, 0);
}
}
            mvRequests.clear();
}
return ret;
};

virtual void abort(vector<RequestPtr>& pRequests) {
        FUNCTION_SCOPE;

bool bAbort = false;
        IMetadata *pHalMeta;
        MINT32 processUniqueKey = 0;

for (auto req:pRequests) {
            bAbort = false;
            pHalMeta = req->mIMetadataHal->acquire();
if (!IMetadata::getEntry<MINT32>(pHalMeta, MTK_PIPELINE_UNIQUE_KEY, processUniqueKey)) {
MY_LOGW("cannot get unique about MFNR capture");
}

if (m_callbackprt != nullptr) {
MY_LOGD("m_callbackprt is %p", m_callbackprt.get());
/*MFNR plugin callback request to MultiFrameNode */
for (Vector<RequestPtr>::iterator it = mvRequests.begin() ; it != mvRequests.end(); it++) {
if ((*it) == req) {
                        mvRequests.erase(it);
                        m_callbackprt->onAborted(req);
                        bAbort = true;
break;
}
}
} else {
MY_LOGW("callbackptr is null");
}

if (!bAbort) {
MY_LOGW("Desire abort request[%d] is not found", req->mRequestIndex);
}

}
};

virtual void uninit() {
        FUNCTION_SCOPE;
if (mMFProcessor != NULL) {
delete mMFProcessor;
            mMFProcessor = NULL;
}
        mLatestWidth = 0;
        mLatestHeight = 0;
};

virtual ~MFNRProviderImpl() {
        FUNCTION_SCOPE;
};

const char * format2String(MINT format) {
switch(format) {
case NSCam::eImgFmt_RGBA8888:          return "rgba";
case NSCam::eImgFmt_RGB888:            return "rgb";
case NSCam::eImgFmt_RGB565:            return "rgb565";
case NSCam::eImgFmt_STA_BYTE:          return "byte";
case NSCam::eImgFmt_YVYU:              return "yvyu";
case NSCam::eImgFmt_UYVY:              return "uyvy";
case NSCam::eImgFmt_VYUY:              return "vyuy";
case NSCam::eImgFmt_YUY2:              return "yuy2";
case NSCam::eImgFmt_YV12:              return "yv12";
case NSCam::eImgFmt_YV16:              return "yv16";
case NSCam::eImgFmt_NV16:              return "nv16";
case NSCam::eImgFmt_NV61:              return "nv61";
case NSCam::eImgFmt_NV12:              return "nv12";
case NSCam::eImgFmt_NV21:              return "nv21";
case NSCam::eImgFmt_I420:              return "i420";
case NSCam::eImgFmt_I422:              return "i422";
case NSCam::eImgFmt_Y800:              return "y800";
case NSCam::eImgFmt_BAYER8:            return "bayer8";
case NSCam::eImgFmt_BAYER10:           return "bayer10";
case NSCam::eImgFmt_BAYER12:           return "bayer12";
case NSCam::eImgFmt_BAYER14:           return "bayer14";
case NSCam::eImgFmt_FG_BAYER8:         return "fg_bayer8";
case NSCam::eImgFmt_FG_BAYER10:        return "fg_bayer10";
case NSCam::eImgFmt_FG_BAYER12:        return "fg_bayer12";
case NSCam::eImgFmt_FG_BAYER14:        return "fg_bayer14";
default:                               return "unknown";
};
};

private:

    MINT32                          mUniqueKey;
    MINT32                          mOpenId;
    MINT32                          mRealIso;
    MINT32                          mShutterTime;
    MBOOL                           mZSDMode;
    MBOOL                           mFlashOn;

    Vector<RequestPtr>              mvRequests;

    RequestCallbackPtr              m_callbackprt;
    MFProcessor* mMFProcessor = NULL;
    IImageBuffer* mOutImgBuffer = NULL;
uint32_t mLatestWidth = 0;
uint32_t mLatestHeight = 0;
    MINT32 mEnable = 0;
    MINT32 mDump = 0;
// add end
};

REGISTER_PLUGIN_PROVIDER(MultiFrame, MFNRProviderImpl);

主要函数介绍：

在property函数中feature类型设置成TP_FEATURE_MFNR，并设置名称、优先级、最大帧数等等属性。尤其注意mNeedRrzoBuffer属性，一般情况下，多帧算法必须要设置为MTRUE。
在negotiate函数中配置算法需要的输入、输出图像的格式、尺寸。注意，多帧算法有多帧输入，但是只需要一帧输出。因此这里设置了mRequestIndex == 0时才需要mOBufferFull。也就是只有第一帧才有输入和输出，其它帧只有输入。
另外，还在negotiate函数中获取上层传下来的metadata参数，根据参数决定算法是否运行。
在process函数中接入算法。第一帧时创建算法接口类对象，然后每一帧都调用算法接口函数addFrame加入，最后一帧再调用算法接口函数process进行处理并获取输出。

2.3.4 mtkcam3/3rdparty/customer/Android.mk

最终vendor.img需要的目标共享库是libmtkcam_3rdparty.customer.so。因此，我们还需要修改Android.mk，使模块libmtkcam_3rdparty.customer依赖libmtkcam.plugin.tp_mfnr。

    diff --git a/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/customer/Android.mk b/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/customer/Android.mk
index ff5763d3c2..5e5dd6524f 100755
--- a/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/customer/Android.mk
+++ b/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/customer/Android.mk
@@ -77,6 +77,12 @@ LOCAL_SHARED_LIBRARIES += libyuv.vendor
LOCAL_WHOLE_STATIC_LIBRARIES += libmtkcam.plugin.tp_watermark
endif

+ifeq ($(QXT_MFNR_SUPPORT), yes)
+LOCAL_SHARED_LIBRARIES += libmultiframe
+LOCAL_SHARED_LIBRARIES += libyuv.vendor
+LOCAL_WHOLE_STATIC_LIBRARIES += libmtkcam.plugin.tp_mfnr
+endif
+
# for app super night ev decision (experimental for customer only)
LOCAL_WHOLE_STATIC_LIBRARIES += libmtkcam.control.customersupernightevdecision
################################################################################

2.3.5 移除MTK示例的MFNR算法

一般情况下，MFNR 算法同一时间只允许运行一个。因此，需要移除 MTK 示例的 MFNR 算法。我们可以使用宏控来移除，这里就简单粗暴，直接注释掉了。

    diff --git a/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/Android.mk b/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/Android.mk
index 4e2bc68dff..da98ebd0ad 100644
--- a/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/Android.mk
+++ b/vendor/mediatek/proprietary/hardware/mtkcam3/3rdparty/mtk/Android.mk
@@ -118,7 +118,7 @@ LOCAL_SHARED_LIBRARIES += libfeature.stereo.provider

#-----------------------------------------------------------
 ifneq ($(strip $(MTKCAM_HAVE_MFB_SUPPORT)),0)
-LOCAL_WHOLE_STATIC_LIBRARIES += libmtkcam.plugin.mfnr
+#LOCAL_WHOLE_STATIC_LIBRARIES += libmtkcam.plugin.mfnr
 endif
#4 Cell
LOCAL_WHOLE_STATIC_LIBRARIES += libmtkcam.plugin.remosaic

三、自定义metadata

添加metadata是为了让APP层能够通过metadata传递相应的参数给HAL层，以此来控制算法在运行时是否启用。APP层是通过CaptureRequest.Builder.set(@NonNull Key<T> key, T value)来设置参数的。由于MTK原生相机APP没有多帧降噪模式，因此，我们自定义metadata来验证集成效果。

vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag.h：

    diff --git a/vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag.h b/vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag.h
index b020352092..714d05f350 100755
--- a/vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag.h
+++ b/vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag.h
@@ -602,6 +602,7 @@ typedef enum mtk_camera_metadata_tag {
MTK_FLASH_FEATURE_END,

QXT_FEATURE_WATERMARK = QXT_FEATURE_START,
+    QXT_FEATURE_MFNR,
QXT_FEATURE_END,
} mtk_camera_metadata_tag_t;

vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag_info.inl：

    diff --git a/vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag_info.inl b/vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag_info.inl
index 1b4fc75a0e..cba4511511 100755
--- a/vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag_info.inl
+++ b/vendor/mediatek/proprietary/hardware/mtkcam/include/mtkcam/utils/metadata/client/mtk_metadata_tag_info.inl
@@ -95,6 +95,8 @@ _IMP_SECTION_INFO_(QXT_FEATURE,      "com.qxt.camera")

_IMP_TAG_INFO_( QXT_FEATURE_WATERMARK,
                 MINT32,     "watermark")
+_IMP_TAG_INFO_( QXT_FEATURE_MFNR,
+                MINT32,     "mfnr")

/******************************************************************************
  *

vendor/mediatek/proprietary/hardware/mtkcam/utils/metadata/vendortag/VendorTagTable.h :

    diff --git a/vendor/mediatek/proprietary/hardware/mtkcam/utils/metadata/vendortag/VendorTagTable.h b/vendor/mediatek/proprietary/hardware/mtkcam/utils/metadata/vendortag/VendorTagTable.h
index 33e581adfd..4f4772424d 100755
--- a/vendor/mediatek/proprietary/hardware/mtkcam/utils/metadata/vendortag/VendorTagTable.h
+++ b/vendor/mediatek/proprietary/hardware/mtkcam/utils/metadata/vendortag/VendorTagTable.h
@@ -383,6 +383,8 @@ static auto& _QxtFeature_()
     sInst = {
_TAG_(QXT_FEATURE_WATERMARK,
"watermark",   TYPE_INT32),
+        _TAG_(QXT_FEATURE_MFNR,
+            "mfnr",   TYPE_INT32),
};
//
return sInst;

vendor/mediatek/proprietary/hardware/mtkcam/utils/metastore/metadataprovider/constructStaticMetadata.cpp :

    diff --git a/vendor/mediatek/proprietary/hardware/mtkcam/utils/metastore/metadataprovider/constructStaticMetadata.cpp b/vendor/mediatek/proprietary/hardware/mtkcam/utils/metastore/metadataprovider/constructStaticMetadata.cpp
index 591b25b162..9c3db8b1d1 100755
--- a/vendor/mediatek/proprietary/hardware/mtkcam/utils/metastore/metadataprovider/constructStaticMetadata.cpp
+++ b/vendor/mediatek/proprietary/hardware/mtkcam/utils/metastore/metadataprovider/constructStaticMetadata.cpp
@@ -583,10 +583,12 @@ updateData(IMetadata &rMetadata)
{
         IMetadata::IEntry qxtAvailRequestEntry = rMetadata.entryFor(MTK_REQUEST_AVAILABLE_REQUEST_KEYS);
         qxtAvailRequestEntry.push_back(QXT_FEATURE_WATERMARK , Type2Type< MINT32 >());
+        qxtAvailRequestEntry.push_back(QXT_FEATURE_MFNR , Type2Type< MINT32 >());
         rMetadata.update(qxtAvailRequestEntry.tag(), qxtAvailRequestEntry);

         IMetadata::IEntry qxtAvailSessionEntry = rMetadata.entryFor(MTK_REQUEST_AVAILABLE_SESSION_KEYS);
         qxtAvailSessionEntry.push_back(QXT_FEATURE_WATERMARK , Type2Type< MINT32 >());
+        qxtAvailSessionEntry.push_back(QXT_FEATURE_MFNR , Type2Type< MINT32 >());
         rMetadata.update(qxtAvailSessionEntry.tag(), qxtAvailSessionEntry);
}
#endif
@@ -605,7 +607,7 @@ updateData(IMetadata &rMetadata)
// to store manual update metadata for sensor driver.
             IMetadata::IEntry availCharactsEntry = rMetadata.entryFor(MTK_REQUEST_AVAILABLE_CHARACTERISTICS_KEYS);
             availCharactsEntry.push_back(MTK_MULTI_CAM_FEATURE_SENSOR_MANUAL_UPDATED , Type2Type< MINT32 >());
-            rMetadata.update(availCharactsEntry.tag(), availCharactsEntry);
+            rMetadata.update(availCharactsEntry.tag(), availCharactsEntry);
}
if(physicIdsList.size() > 1)
{

前面这些步骤完成之后，集成工作就基本完成了。我们需要重新编译一下系统源码，为节约时间，也可以只编译vendor.img。

四、APP调用算法

验证算法我们无需再重新写APP，继续使用《MTK HAL算法集成之单帧算法》中的APP代码，只需要将KEY_WATERMARK的值改为"com.qxt.camera.mfnr"即可。为样机刷入系统整包或者vendor.img，开机后，安装demo验证。我们来拍一张看看效果：

image

可以看到，集成后，这个模拟MFNR的多帧算法已经将连续的4帧图像缩小并拼接成一张图了。

五、结语

真正的多帧算法要复杂一些，例如，MFNR算法可能会根据曝光值决定是否启用，光线好就不启用，光线差就启用；HDR算法，可能会要求获取连续几帧不同曝光的图像。可能还会有智能的场景检测等等。但是不管怎么变，多帧算法大体上的集成步骤都是类似的。如果遇到不同的需求，可能要根据需求灵活调整一下代码。

原文链接：https://www.jianshu.com/p/f0

参考文献：

【腾讯文档】Camera学习知识库
https://docs.qq.com/doc/DSWZ6dUlNemtUWndv

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MTK 多帧算法集成实现流程