第14讲从CameraServer角度详解Camera启动性能 - Android Camera性能分析|极客笔记

本讲是Android Camera性能分析专题的第14讲，我们介绍从CameraServer角度详解Camera启动性能，包括如下内容：

从CameraServer角度详解Camera启动性能
CameraServer核心函数流程拆解

资源	描述
在线课程	极客笔记在线课程
知识星球	星球名称：深入浅出Android Camera 星球ID: 17296815
Wechat	极客笔记圈

从CameraServer角度详解Camera启动性能

模块	开始点	结束点
App	点击Camera App Icon	开始调用connectDevice
HAL	开始调用connectDevice	调用connectDevice结束
App	调用connectDevice结束	开始调用endConfigure
HAL	开始调用endConfigure	调用endConfigure结束
App	调用endConfigure结束	调用submitRequestList
HAL	调用submitRequestList	CameraServer收到第一帧

CameraServer核心函数流程拆解

getCameraCharacteristics

1.shouldRejectSystemCameraConnection
2.getCameraCharacteristicsLocked // 从CameraProviderManager中获取CameraCharacteristics
3.getCameraCharacteristics::checkPermission

getCameraCharacteristics

connectDevice

会调用到HAL的CameraHal::openSession

1.validateConnectLocked
2.CameraDeviceClient::initializeImpl
      Camera2ClientBase::initializeImpl
            Camera3Device::initialize
                CameraHal::openSession
3.finishConnectLocked

connectDevice

createDefaultRequest

会调用到HAL的CameraHal::constructDefaultRequestSettings

1.CameraDeviceClient::createDefaultRequest
    Camera3Device::createDefaultRequest
        CameraHal::constructDefaultRequestSettings

createDefaultRequest

beginConfigure

CameraDeviceClient::beginConfigure //Not implemented yet

createStream

核心在创建 Camera3OutputStream

CameraDeviceClient::createStream
    SessionConfigurationUtils::createSurfaceFromGbp
        query(width,height,format,dataspace)
    Camera3Device::createStream
        new Camera3OutputStream
    setStreamTransformLocked

createStream

endConfigure

会调用到HAL的CameraHal::configureStreams

CameraDeviceClient::endConfigure
    Camera3Device::configureStreams
        Camera3Stream::startConfiguration
        CameraHal::configureStreams
        Camera3Stream::finishConfiguration
        Boost priority of request thread to SCHED_FIFO

endConfigure

submitRequestList

CaptureRequest送下来后会等待Active

CameraDeviceClient::submitRequestList
    Camera3Device::setStreamingRequestList
        Camera3Device::RequestThread::setRepeatingRequests
        Camera3Device::waitUntilStateThenRelock

submitRequestList

Request thread线程开始给HAL送Request，调用 CameraHal::processBatchCaptureRequests

Camera3Device::RequestThread::threadLoop
    Camera3Device::RequestThread::waitForNextRequestBatch
    Camera3Device::RequestThread::prepareHalRequests
    Camera3Device::RequestThread::sendRequestsBatch
        CameraHal::processBatchCaptureRequests

sendRequestsBatch

StatusTracker通知status变化：

Camera3Device::notifyStatus
    Camera3Device::internalUpdateStatusLocked
        mStatusChanged.broadcast
        Camera2ClientBase::notifyActive
            CameraService::BasicClient::startCameraStreamingOps

startCameraStreamingOps

Stream 0: first full buffer

HAL回调processCaptureResult后，如果有Buffer，则取出来 queueBuffer给 Consumer

Camera3Device::processCaptureResult
  Camera3OutputUtils::returnAndRemovePendingOutputBuffers
    Camera3OutputUtils::returnOutputBuffers
      Camera3Stream::returnBuffer
        Camera3OutputStream::returnBufferLocked
          Camera3IOStreamBase::returnAnyBufferLocked
            Camera3OutputStream::returnBufferCheckedLocked
              Camera3OutputStream::queueBufferToConsumer