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、多帧拍照请求概览
二、多帧拍照回帧概览

一、多帧拍照请求概览

多帧拍照请求概览如下：

多帧拍照请求

1.1 APP 下发拍照请求到 Camera Framework

1.1.1 Trace关键字如下：

APP:
deliverInputEvent: app 点击事件处理
CameraUnitCamera2ImplTakePicture：app 下发拍照请求
binder transaction ：通过bind 跟FWK交互

FWK:
binder reply ：响应app 下发的bind
submitRequestList：Camera FWK提交拍照请求给HAL，并包含拍照帧数
captureList
submitRequestsHelper
createCaptureRequest :比如多帧会下发4 帧
queueRequestList
unpauseForNewRequests:暂停新的拍照请求

1.1.2 详细请看下面trace 截图

1.1.3 下发4帧请求createCaptureRequest

请求4帧

1.2 Camera Framework下发拍照请求到 camera HAL中

1.2.1 Trace关键字如下：

FWK:
sendRequestsBatch:Camera FWK 下发批处理请求
CameraHal::processBatchCaptureRequests：Camera FWK 每帧请求到HAL
HIDL::ICameraDeviceSession::processCaptureRequest_3_4::client：Camera 向Camera HAL请求一帧
binder transaction

CAM HAL：
binder reply
HIDL::ICameraDeviceSession::processCaptureRequest_3_4::server ：Camera HAL接受处理Camera FWK 请求
processCaptureRequest_3_4
processCaptureRequest
submitOneRequest
onRequest_EvaluateRequest
evaluateRequest
FeatureSettingPolicy::evaluateRequest
evaluateCaptureSetting
negotiate
onRequest_ProcessEvaluatedFrame
processEvaluatedFrame
onProcessEvaluatedFrame
submitZslRequest：Camera HAL 提交拍照请求帧
makePipelineFrame
queue|requestNo:97 frameNo:97
onFrameUpdated

1.2.2 详细请看下面trace 截图

1.2.3 拍照log关键字：

control.captureIntent:2|capture req#
拍照log 如下：

01-02 09:05:10.695442  1161  1642 I mtkcam-PipelineModelSession: [submitRequest] <Default/1> requestNo:94 { repeating:0 control.aeTargetFpsRange:5,30 control.captureIntent:2 control.enableZsl:1 control.processRawEn:0 control.mode:1 control.sceneMode:0 control.videoStabilizationMode:0 edge.mode:2 }
01-02 09:05:10.695560  1161  1642 I mtkcam-FeatureSettingPolicy: [evaluateCaptureSetting] (0xb4000075a3a43020) capture req#:94
01-02 09:05:10.734815  1161  1642 I mtkcam-PipelineModelSession: [submitRequest] <Default/1> requestNo:95 { repeating:0 control.aeTargetFpsRange:5,30 control.captureIntent:2 control.enableZsl:1 control.processRawEn:0 control.mode:1 control.sceneMode:0 control.videoStabilizationMode:0 edge.mode:2 }
01-02 09:05:10.734937  1161  1642 I mtkcam-FeatureSettingPolicy: [evaluateCaptureSetting] (0xb4000075a3a43020) capture req#:95
01-02 09:05:10.770126  1161  1645 I mtkcam-PipelineModelSession: [submitRequest] <Default/1> requestNo:96 { repeating:0 control.aeTargetFpsRange:5,30 control.captureIntent:2 control.enableZsl:1 control.processRawEn:0 control.mode:1 control.sceneMode:0 control.videoStabilizationMode:0 edge.mode:2 }
01-02 09:05:10.770526  1161  1645 I mtkcam-FeatureSettingPolicy: [evaluateCaptureSetting] (0xb4000075a3a43020) capture req#:96
01-02 09:05:10.795720  1161  1645 I mtkcam-PipelineModelSession: [submitRequest] <Default/1> requestNo:97 { repeating:0 control.aeTargetFpsRange:5,30 control.captureIntent:2 control.enableZsl:1 control.processRawEn:0 control.mode:1 control.sceneMode:0 control.videoStabilizationMode:0 edge.mode:2 }
01-02 09:05:10.795846  1161  1645 I mtkcam-FeatureSettingPolicy: [evaluateCaptureSetting] (0xb4000075a3a43020) capture req#:97
01-02 09:05:10.958217  1161  1642 I mtkcam-FeatureSettingPolicy_ISP: [evaluateCaptureSetting] (0xb4000075a3be0c58) capture req#:94 (count:4, index:0)
01-02 09:05:13.924135  1161  1644 I mtkcam-FeatureSettingPolicy_ISP: [evaluateCaptureSetting] (0xb400007592195818) capture req#:94 (count:1, index:0)

二、多帧拍照回帧概览

2.1 多帧拍照回帧概览如下：

2.2 Camera HAL 请求返回帧处理

2.2.1 Trace 关键字如下：

CAM HAL:
onDispatchFrame|requestNo:97 frameNo:97 nodeId:1 ：处理拍照请求帧97
CaptureNode::queue

P2_Capture:enque()
MWFrameRequest::createRequests->createP2ImgMap

p2a:process|r97f97s1 ：RequestNo : 97 FrameNo: 97 SensorID :1 前摄

p2a:finish|r97f971)
P2_Capture:notifyRelease()
P2:ApplyRelease
P2:DispatchFrame

processCaptureResult
convertToHidlCaptureResults
HIDL::ICameraDeviceCallback::processCaptureResult_3_4::client

2.3 Camera FWK && Camera APP 请求返回帧处理

CAM FWK:
HIDL::ICameraDeviceCallback::processCaptureResult_3_4::server
queueBuffer

APP:
binder reply
queueBuffer
ImageReader ：APP 接收到 Camera FWK PostView

2.4 MTK BSS效果选帧处理

效果处理：
BSS(Best Shot Selection)MTK 最佳选帧算法，拍照返回帧的效果的一些处理，主要优化图片质量效果

packIspTuningDataToHeap：4帧拍照会有5个，每帧一个，在MFNR处理后会还有一个
downSampleImageBufferHeap
doZipWithBss

2.5 app 请求返回帧处理

APP拿到请求返回帧后对图片进行处理，
比如多帧算法，人脸识别，美颜算法，滤镜，镜像等等，app 处理完之后就开始压jpeg进行图片保存。
大致流程如下：

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

友情推荐：

Android 开发干货集锦

至此，本篇已结束。转载网络的文章，小编觉得很优秀，欢迎点击阅读原文，支持原创作者，如有侵权，恳请联系小编删除，欢迎您的建议与指正。同时期待您的关注，感谢您的阅读，谢谢！

点击阅读原文，为大佬点赞！