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、Camx 代码结构
二、Camx 编译
三、Camx 代码流程分析
四、Camx 调试
一、Camx 代码结构
目前主流的机型都使用camx架构，这个架构和之前架构的主要区别就是 芯片接口层的代码从hardware/qcom迁移到vendor/qcom/proprietary/下面，我们主要关注的camera hal层的源码也是放在vendor/qcom/proprietary/camx/下面。
1.1 camera 相关代码目录
二、camx 编译
camx的核心目录是vendor/qcom/proprietary/camx/src/目录下面：
total 40drwxrwxr-x 10 lxl lxl 40964月4 10:52 ./drwxrwxr-x4 lxl lxl 40964月4 10:52 ../drwxrwxr-x3 lxl lxl 40964月4 10:52 chiiqutils/drwxrwxr-x7 lxl lxl 40964月4 10:56 core/drwxrwxr-x7 lxl lxl 40964月4 10:52 csl/drwxrwxr-x 14 lxl lxl 40964月4 10:52 hwl/drwxrwxr-x3 lxl lx 40964月4 10:52 lib/drwxrwxr-x3 lxl lxl 40964月4 10:52 osutils/drwxrwxr-x 11 lxl lxl 40964月4 10:52 swl/drwxrwxr-x3 lxl lxl 40964月4 10:52 utils/核心的Android.mk在./lib/build/android/Android.mk中。
其中包括的静态库如下：
# Libraries to linkLOCAL_STATIC_LIBRARIES := \libcamxcore \libcamxchi\libcamxcsl\libcamxofflinestats \libnc \libcamxncs\libifestriping\libstripingLOCAL_WHOLE_STATIC_LIBRARIES := \libcamxdspstreamer\libcamxhwlbps \libcamxgenerated\libcamxhal\libcamxhalutils \libcamxhwlfd\libcamxhwlife \libcamxhwlipe \libcamxhwliqmodule\libcamxswlfdmanager \libcamxswljpeg\libcamxhwljpeg\libcamxhwllrme\libcamxswlransac\libcamxhwltitan17x\libcamxiqsetting\libcamxosutils\libcamxstats\libcamxsensor \libcamxutils这些静态库都是camx或者其他的目录下编译的，编译工程的时候，我们要先编译这些静态库，然后编译camx的动态库（/vendor/lib/hw/camera.qcom.so）。
三、camx 代码流程分析
camera.provider中如何实现到camera hal层的跳跃，camera service调用到camera provider中的接口方法，现在调用到 camera provider中的hardware/interfaces/camera/device/3.2/default/CameraDeviceSession.cpp中的processCaptureRequest(...)方法，最终会调用到：
status_t ret = mDevice->ops->process_capture_request(mDevice, &halRequest);这个mDevice->ops 就是hardware/libhardware/include/hardware/camera3.h中的 camera3_device_ops 结构体： （参考：https://www.jianshu.com/p/099cc3b0ab25）
typedef struct camera3_device_ops {int (*initialize)(const struct camera3_device *,const camera3_callback_ops_t *callback_ops);int (*configure_streams)(const struct camera3_device *,camera3_stream_configuration_t *stream_list);int (*register_stream_buffers)(const struct camera3_device *,const camera3_stream_buffer_set_t *buffer_set);const camera_metadata_t* (*construct_default_request_settings)(const struct camera3_device *,int type);int (*process_capture_request)(const struct camera3_device *,camera3_capture_request_t *request);void (*get_metadata_vendor_tag_ops)(const struct camera3_device*,vendor_tag_query_ops_t* ops);void (*dump)(const struct camera3_device *, int fd);int (*flush)(const struct camera3_device *); /* reserved for future use */void *reserved[8];} camera3_device_ops_t;camera3_device_ops_t 映射函数指针操作：hardware/libhardware/modules/camera/3_0/Camera.cpp
const camera3_device_ops_t Camera::sOps = {.initialize = default_camera_hal::initialize,.configure_streams = default_camera_hal::configure_streams,.register_stream_buffers = default_camera_hal::register_stream_buffers,.construct_default_request_settings= default_camera_hal::construct_default_request_settings,.process_capture_request = default_camera_hal::process_capture_request,.get_metadata_vendor_tag_ops = NULL,.dump = default_camera_hal::dump,.flush = default_camera_hal::flush,.reserved = {0},};这样找到在camera hal层的函数指针的映射关系。
映射到：vendor/qcom/proprietary/camx/src/core/hal/camxhal3entry.cpp中的static Dispatch g_dispatchHAL3(&g_jumpTableHAL3);：
/// Array containing camera3_device_ops_t methodsstatic camera3_device_ops_t g_camera3DeviceOps ={CamX::initialize,CamX::configure_streams,NULL,CamX::construct_default_request_settings,CamX::process_capture_request,NULL,CamX::dump,CamX::flush,{0},};定义了g_camera3DeviceOps变量：
/// Array containing camera3_device_ops_t methodsstatic camera3_device_ops_t g_camera3DeviceOps ={CamX::initialize,CamX::configure_streams,NULL,CamX::construct_default_request_settings,CamX::process_capture_request,NULL,CamX::dump,CamX::flush,{0},};并在\vendor\qcom\proprietary\camx\src\core\hal\camxhaldevice.cpp的Initialize方法中通过GetCamera3DeviceOps获取，建立联系：
CamxResult HALDevice::Initialize(const HwModule* pHwModule,UINT32cameraId){CamxResult result = CamxResultSuccess;m_cameraId = cameraId;if (CamxResultSuccess == result){m_camera3Device.hwDevice.tag = HARDWARE_DEVICE_TAG; /// @todo (CAMX-351) Get from local macrom_camera3Device.hwDevice.version = CAMERA_DEVICE_API_VERSION_3_3;m_camera3Device.hwDevice.close = reinterpret_cast(GetHwDeviceCloseFunc());m_camera3Device.pDeviceOps = reinterpret_cast(GetCamera3DeviceOps());m_camera3Device.pPrivateData = this;// NOWHINE CP036a: Need exception herem_camera3Device.hwDevice.pModule = const_cast(pHwModule);m_HALCallbacks.ProcessCaptureResult = ProcessCaptureResult;m_HALCallbacks.NotifyResult = Notify;CamX::ChiOverrideBypass(&m_HALCallbacks);}m_pHALSession = NULL;Utils::Memset(m_flushRequest, 0, sizeof(m_flushRequest));return result;}看一下g_jumpTableHAL3 变量：在vendor/qcom/proprietary/camx/src/core/hal/camxhal3.cpp中定义的:
// Jump table for HAL3JumpTableHAL3 g_jumpTableHAL3 ={open,get_number_of_cameras,get_camera_info,set_callbacks,get_vendor_tag_ops,open_legacy,set_torch_mode,init,parallelQuery,setCallBack,get_tag_count,get_all_tags,get_section_name,get_tag_name,get_tag_type,close,initialize,configure_streams,construct_default_request_settings,process_capture_request,dump,flush,camera_device_status_change,torch_mode_status_change,process_capture_result,notify};这儿直接构成了指针函数的映射关系（对应camxhaldevice.cpp中的函数）。vendor/qcom/proprietary/camx/src/core/chi/camxchitypes.h中定义了CHIAppCallbacks结构体，如下：
struct CHIAppCallbacks{/// @brief Called by the driver to get number of camerasINT(*CHIGetNumCameras)(UINT32* pNumFwCameras,UINT32* pNumLogicalCameras); /// @brief Called by the driver to get the camera info for the camera idCamxResult (*CHIGetCameraInfo)(UINT32cameraId,CameraInfo* pCameraInfo); /// @brief Defines the prototype for the device status change callback method from to the framework. Please refer to///the camera_device_status_change documentation in hardware/camera_common.h.VOID (*CHIInitializeOverrideSession)(UINT32 cameraId,const Camera3Device* pCamera3Device,const HALCallbacks*pHALCallbacks,Camera3StreamConfig* pStreamConfig,BOOL*isOverrideEnabled,VOID** ppPrivate); /// @brief Defines the prototype for the torch mode status change callback method from to the framework. Please refer to///the torch_mode_status_change documentation in hardware/camera_common.h.VOID (*CHIFinalizeOverrideSession)(const Camera3Device* pCamera3Device,UINT64*pSession,VOID** ppPrivate); /// @brief Called by the driver to inform about session closingVOID (*CHITeardownOverrideSession)(const Camera3Device* pCamera3Device,UINT64*pSession,VOID*pPrivate); /// @brief Called by the driver to pass on capture request call to CHIINT (*CHIOverrideProcessRequest)(const Camera3Device*pCamera3Device,Camera3CaptureRequest*pCaptureRequest,VOID* pPrivate); /// @brief Called by the driver to allow for additional override processing during open()INT(*CHIExtendOpen)(UINT32cameraId,VOID* pPrivateData); /// @brief Called by the driver to allow for additional override processing during close()INT(*CHIExtendClose)(UINT32cameraId,VOID* pPrivateData); /// @brief Called by the driver to allow override to remap special camera IDs into logical camera IDsUINT32(*CHIRemapCameraId)(UINT32frameworkCameraId,CameraIdRemapMode mode); /// @brief Interface to allow various override-specific settings to be toggled.UINT32(*CHIModifySettings)(VOID* pPrivateData); /// @brief Get any vendor tag specific request settings the override wants to get added to the default settingsVOID (*CHIGetDefaultRequestSettings)(UINT32 frameworkCameraId,INTrequestTemplate,const Metadata** pAdditionalMetadata); /// @brief Called by the driver to allow for flush()INT(*CHIOverrideFlush)(const Camera3Device*pCamera3Device);INT(*CHIParallelQuery) (INT num, char* list[]);INT(*CHISetCallback) (void*); }; typedef VOID(*CHIHALOverrideEntry)(CHIAppCallbacks* pCHIAppCallbacks);这个结构体是函数指针，映射关系：vendor/qcom/proprietary/camx/src/core/hal/camxhal3module.h中定义了 CHIAppCallbacks m_ChiAppCallbacks;
CHIAppCallbacks m_ChiAppCallbacks;///< CHI HAL override entryvendor/qcom/proprietary/camx/src/core/hal/camxhal3module.cpp中的 HAL3Module构造函数中，存在下面的执行语句：
CHIHALOverrideEntry funcCHIHALOverrideEntry =reinterpret_cast(CamX::OsUtils::LibGetAddr(m_hChiOverrideModuleHandle, "chi_hal_override_entry")); if (NULL != funcCHIHALOverrideEntry){funcCHIHALOverrideEntry(&m_ChiAppCallbacks); //对应到 chxextensioninterface.cpp 中的chi_hal_override_entry函数 CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIGetNumCameras);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIGetCameraInfo);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIFinalizeOverrideSession);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIInitializeOverrideSession);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIOverrideProcessRequest);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIOverrideFlush);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHITeardownOverrideSession);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIExtendOpen);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIExtendClose);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIRemapCameraId);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIModifySettings);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHIParallelQuery);CAMX_ASSERT(NULL != m_ChiAppCallbacks.CHISetCallback); if ((NULL != m_ChiAppCallbacks.CHIGetNumCameras) &&(NULL != m_ChiAppCallbacks.CHIGetCameraInfo) &&(NULL != m_ChiAppCallbacks.CHIFinalizeOverrideSession) &&(NULL != m_ChiAppCallbacks.CHIInitializeOverrideSession) &&(NULL != m_ChiAppCallbacks.CHIOverrideProcessRequest)&&(NULL != m_ChiAppCallbacks.CHIOverrideFlush) &&(NULL != m_ChiAppCallbacks.CHITeardownOverrideSession) &&(NULL != m_ChiAppCallbacks.CHIExtendOpen)&&(NULL != m_ChiAppCallbacks.CHIExtendClose) &&(NULL != m_ChiAppCallbacks.CHIRemapCameraId) &&(NULL != m_ChiAppCallbacks.CHIModifySettings)&&(NULL != m_ChiAppCallbacks.CHIParallelQuery) &&(NULL != m_ChiAppCallbacks.CHISetCallback)){CAMX_LOG_WARN(CamxLogGroupHAL, "CHI Module library function pointers exchanged");}}m_ChiAppCallbacks 通过 funcCHIHALOverrideEntry 映射到 chi_hal_override_entry这个 chi_hal_override_entry 就是指vendor/qcom/proprietary/chi-cdk/vendor/chioverride/default/chxextensioninterface.cpp中的 chi_hal_override_entry 函数，如下：
void chi_hal_override_entry(chi_hal_callback_ops_t* callbacks){ExtensionModule* pExtensionModule = ExtensionModule::GetInstance(); CHX_ASSERT(NULL != callbacks); if (NULL != pExtensionModule){callbacks->chi_get_num_cameras= chi_get_num_cameras;callbacks->chi_get_camera_info= chi_get_camera_info;callbacks->chi_initialize_override_session= chi_initialize_override_session;callbacks->chi_finalize_override_session= chi_finalize_override_session;callbacks->chi_override_process_request = chi_override_process_request;callbacks->chi_teardown_override_session= chi_teardown_override_session;callbacks->chi_extend_open= chi_extend_open;callbacks->chi_extend_close = chi_extend_close;callbacks->chi_remap_camera_id= chi_remap_camera_id;callbacks->chi_modify_settings= chi_modify_settings;callbacks->chi_get_default_request_settings = chi_get_default_request_settings;callbacks->chi_override_flush = chi_override_flush;callbacks->chi_parallelquery= chi_parallelquery;callbacks->chi_setcallback= chi_setcallback;}}这样就建立了 CHIAppCallbacks 中函数指针的一一映射关系。
vendor/qcom/proprietary/chi-cdk/vendor/chioverride/default/chxextensionmodule.cpp 中的 ExtensionModule::OverrideProcessRequest函数中执行了m_pUsecaseFactory->CreateUsecaseObject，如下：
m_pSelectedUsecase[logicalCameraId] =m_pUsecaseFactory->CreateUsecaseObject(&m_logicalCameraInfo[logicalCameraId],static_cast(m_SelectedUsecaseId[logicalCameraId]),m_pStreamConfig[logicalCameraId]);直接调用到：vendor/qcom/proprietary/chi-cdk/vendor/chioverride/default/chxusecaseutils.cpp中的 UsecaseFactory::CreateUsecaseObject 函数：
Usecase* UsecaseFactory::CreateUsecaseObject(LogicalCameraInfo*pLogicalCameraInfo, ///< camera infoUsecaseId usecaseId,///< Usecase Idcamera3_stream_configuration_t* pStreamConfig)///ppDeviceInfo[0]->cameraId;CHX_LOG_ERROR("UsecaseFactory::CreateUsecaseObject id = %d", usecaseId);switch (usecaseId){case UsecaseId::PreviewZSL:pUsecase = AdvancedCameraUsecase::Create(pLogicalCameraInfo, pStreamConfig, usecaseId);break;case UsecaseId::MultiCamera:pUsecase = UsecaseMultiCamera::Create(pLogicalCameraInfo, pStreamConfig);break;case UsecaseId::MultiCameraVR:pUsecase = UsecaseMultiVRCamera::Create(pLogicalCameraInfo, pStreamConfig);break;case UsecaseId::MFNR:pUsecase = UsecaseMFNR::Create(camera0Id, pStreamConfig);break;case UsecaseId::QuadCFA:pUsecase = UsecaseQuadCFA::Create(pLogicalCameraInfo, pStreamConfig);break;case UsecaseId::Torch:pUsecase = UsecaseTorch::Create(camera0Id, pStreamConfig);break;default:pUsecase = AdvancedCameraUsecase::Create(pLogicalCameraInfo, pStreamConfig, usecaseId);break;} return pUsecase;}enum class UsecaseId{NoMatch = 0,Default = 1,Preview = 2,PreviewZSL= 3,MFNR= 4,MFSR= 5,MultiCamera = 6,QuadCFA = 7,RawJPEG = 8,MultiCameraVR = 9,Torch = 10,YUVInBlobOut= 11,MaxUsecases = 12,};前置摄像头的UsecaseId是 PreviewZSL，是单摄，后置摄像头的UsecaseId是 MultiCamera，是多摄。
camx-usecase
vendor/qcom/proprietary/camx/src/core/chi/camxchi.cpp中的 ChiEntry函数如下：
/// ChiEntryCAMX_VISIBILITY_PUBLIC VOID ChiEntry(ChiContextOps* pChiContextOps){if (NULL != pChiContextOps){pChiContextOps->size = sizeof(ChiContextOps); pChiContextOps->majorVersion = CHI_API_MAJOR_VERSION;pChiContextOps->minorVersion = CHI_API_MINOR_VERSION;pChiContextOps->pOpenContext = CamX::ChiOpenContext;pChiContextOps->pCloseContext= CamX::ChiCloseContext;pChiContextOps->pGetNumCameras = CamX::ChiGetNumCameras;pChiContextOps->pGetCameraInfo = CamX::ChiGetCameraInfo;pChiContextOps->pEnumerateSensorModes= CamX::ChiEnumerateSensorModes;pChiContextOps->pCreatePipelineDescriptor= CamX::ChiCreatePipelineDescriptor;pChiContextOps->pDestroyPipelineDescriptor = CamX::ChiDestroyPipelineDescriptor;pChiContextOps->pCreateSession = CamX::ChiCreateSession;pChiContextOps->pDestroySession= CamX::ChiDestroySession;pChiContextOps->pFlushSession= CamX::ChiFlushSession;pChiContextOps->pActivatePipeline= CamX::ChiActivatePipeline;pChiContextOps->pDeactivatePipeline= CamX::ChiDeactivatePipeline;pChiContextOps->pSubmitPipelineRequest = CamX::ChiSubmitPipelineRequest;pChiContextOps->pTagOps= CamX::ChiGetTagOps;} // This is the workaround for presil HAL3test on Windows// On Device, set_camera_metadata_vendor_ops will be call the set the// static vendor tag operation in camera_metadata.c//// On Windows side, theoretically hal3test should mimic what Android framework// does and call the set_camera_metadata_vendor_ops function in libcamxext library// However, in Windows, if both hal3test.exe and hal.dll link to libcamxext library,// there are two different instance of static varibles sit in different memory location.// Even if set_camera_metadata_vendor_ops is called in hal3test, when hal try to// access to vendor tag ops, it is still not set.//// This is also a workaround to call vendor tag ops in Chi at GetNumCameras which happens to get called before// GetVendorTagOpsCamX::g_vendorTagOps.get_all_tags = CamX::ChiGetAllTags;CamX::g_vendorTagOps.get_section_name = CamX::ChiGetSectionName;CamX::g_vendorTagOps.get_tag_count= CamX::ChiGetTagCount;CamX::g_vendorTagOps.get_tag_name = CamX::ChiGetTagName;CamX::g_vendorTagOps.get_tag_type = CamX::ChiGetTagType; set_camera_metadata_vendor_ops(&(CamX::g_vendorTagOps));}这个函数映射关系很重要，也在camx chi中比较常见，直接映射在此文件的CamxChi类中。都是从vendor/qcom/proprietary/chi-cdk/vendor/chioverride/default/chxextensionmodule.cpp中调用过来的。
下面是预览时capture request 处理流程图：
check这段流程的时候我们最关注应该是5个重要的处理类型：
1.UseCase
vendor/qcom/proprietary/chi-cdk/vendor/chioverride/default/chxusecase.h上面有介绍类图。UseCase在camx中很有很多衍生类，这是camx针对不同的stream来建立不同的usecase对象，用来管理选择feature，并且创建 pipeline以及session。2.ChiFeature
vendor/qcom/proprietary/chi-cdk/vendor/chioverride/default/chxfeature.h， usecase选择相应的feature，关联一组pipeline，收到request请求，根据request选择对应的feature。3.Node
vendro/qcom/propriatary/camx/src/core/camxnode.h，下面有类图。Node是camx中非常重要的一个父类，是camx中处理camera 请求的一个中间节点，用于处理pipeline下发的请求，下面有类图介绍，比较重要**的Node子类已经标出来了。4.pipeline
一连串node的集合，通过pipeline下发给各个node处理。5.session
若干个有关联的pipeline的集合，用来管理pipeline，使用pipeline处理请求。
注： Node 节点在camx chi架构中至关重要，数据的处理都是通过封装好的Node节点来进行的。
camxnode结构图：
node节点的创建地方在vendor/qcom/proprietary/camx/src/hwl/titian17x/camxtitian17xfactory.cpp
Node* Titan17xFactory::HwCreateNode(const NodeCreateInputData* pCreateInputData,NodeCreateOutputData*pCreateOutputData) const{Node* pNode = NULL; switch (pCreateInputData->pNodeInfo->nodeId){case AutoFocus:pNode = AutoFocusNode::Create(pCreateInputData, pCreateOutputData);break;case BPS:pNode = BPSNode::Create(pCreateInputData, pCreateOutputData);break;case IFE:pNode = IFENode::Create(pCreateInputData, pCreateOutputData);break;case IPE:pNode = IPENode::Create(pCreateInputData, pCreateOutputData);break;case Sensor:pNode = SensorNode::Create(pCreateInputData, pCreateOutputData);break;case StatsProcessing:pNode = StatsProcessingNode::Create(pCreateInputData, pCreateOutputData);break;case JPEG:pNode = JPEGEncNode::Create(pCreateInputData, pCreateOutputData);break;case JPEGAggregator:pNode = JPEGAggrNode::Create(pCreateInputData, pCreateOutputData);break;case StatsParse:pNode = StatsParseNode::Create(pCreateInputData, pCreateOutputData);break;case ChiExternalNode:pNode = ChiNodeWrapper::Create(pCreateInputData, pCreateOutputData);break;case FDHw:pNode = FDHwNode::Create(pCreateInputData, pCreateOutputData);break;case FDManager:pNode = FDManagerNode::Create(pCreateInputData, pCreateOutputData);break;case OfflineStats:pNode = OfflineStatsNode::Create(pCreateInputData, pCreateOutputData);break;case Torch:pNode = TorchNode::Create(pCreateInputData, pCreateOutputData);break;case LRME:pNode = LRMENode::Create(pCreateInputData, pCreateOutputData);break;case RANSAC:pNode = RANSACNode::Create(pCreateInputData, pCreateOutputData);break;default:CAMX_ASSERT_ALWAYS_MESSAGE("Unexpected node type");break;} return pNode;}
camx_feature：
在vendor/qcom/proprietary/chi-cdk/vendor/chioverride/default/chxadvancedcamerausecase.cpp中的SelectFeatures(…)函数中有这些feature的创建代码。
拍照的场景分为前置和后置，前置是单摄，后置是多摄，前面也有介绍，单摄和多摄使用的usecase是不同:
前置拍照创建的pipeline有：
MiuiZSLSnapshotJpeg at index 0 for session 0, session's pipeline 0, camera id:1MiuiZSLPreviewRaw at index 1 for session 1, session's pipeline 0, camera id:1BinningZSLYuv2Jpeg at index 2 for session 2, session's pipeline 0, camera id:1BinningMerge3YuvCustomTo1Yuv at index 3 for session 3, session's pipeline 0, camera id:1ZSLSnapshotYUV at index 4 for session 4, session's pipeline 0, camera id:1AdvancedAsdMeta at index 5 for session 5, session's pipeline 0, camera id:1SWMFClearShotYuv at index 6 for session 6, session's pipeline 0, camera id:1BinningZSLSnapshotYUV at index 7 for session 7, session's pipeline 0, camera id:1后置拍照创建的pipeline有：
BackCameraJpegEncode at index 0 for session 0, session's pipeline 0, camera id:0MfnrPrefilter at index 1 for session 0, session's pipeline 1, camera id:0MfnrBlend at index 2 for session 0, session's pipeline 2, camera id:0MfnrPostFilter at index 3 for session 0, session's pipeline 3, camera id:0MfnrScale at index 4 for session 0, session's pipeline 4, camera id:0Merge3YuvCustomTo1Yuv at index 5 for session 1, session's pipeline 0, camera id:0ZSLSnapshotYUV at index 6 for session 2, session's pipeline 0, camera id:0ZSLSnapshotYUVAux at index 7 for session 3, session's pipeline 0, camera id:3SWMFSRYuv at index 8 for session 4, session's pipeline 0, camera id:0AdvancedAsdMeta at index 9 for session 5, session's pipeline 0, camera id:0pipeline在camx中的配置文件是：vendor/qcom/proprietary/chi-cdk/vendor/topology/default/titan17x_usecases.xml，编译时会根据此xml的配置生成对应vendor\qcom\proprietary\chi-cdk\vendor\chioverride\default\g_pipelines.h，vendor\qcom\proprietary\chi-cdk\vendor\chioverride\default\build\android\Android.mk:
...$(info $(shell perl $(CAMX_CDK_PATH)/topology/usecaseconverter.pl $(CAMX_VENDOR_PATH)/topology/default/titan17x_usecases.xml $(LOCAL_PATH)/g_pipelines.h))...然后在\vendor\qcom\proprietary\chi-cdk\vendor\chioverride\default\chxusecaseutils.cpp中会根据pStreamConfig->num_streams选择到对应的Usecases（g_pipelines.h中定义）：
// UsecaseSelector::DefaultMatchingUsecaseChiUsecase* UsecaseSelector::DefaultMatchingUsecase(camera3_stream_configuration_t* pStreamConfig){... pSelectedUsecase = &pChiTargetUsecases->pChiUsecases[i];...}DefaultMatchingUsecase方法即在\vendor\qcom\proprietary\chi-cdk\vendor\chioverride\default\chxadvancedcamerausecase.cpp被调用：
CDKResult AdvancedCameraUsecase::SelectUsecaseConfig(LogicalCameraInfo*pCameraInfo, ///< Camera infocamera3_stream_configuration_t* pStreamConfig)///< Stream configuration{...m_pChiUsecase = UsecaseSelector::DefaultMatchingUsecase(pStreamConfig);...}四、Camx 调试log开关
修改\vendor\qcom\proprietary\camx\src\core\camxsettings.xml设置 log 打印级别，如：
overrideLogLevels=0x1FlogInfoMask=0x40080logVerboseMask=0x40000原文链接：https://www.cnblogs.com/blogs-of-lxl/p/10668554.html
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