MediaPipe框架源码分析

背景

MediaPipe的介绍。
源代码位置 https://github.com/google/mediapipe

框架介绍（截至2022-01）

主要是graph

官方介绍说明
https://google.github.io/mediapipe/framework_concepts/framework_concepts.html#the-basics

从hello-world开始

hello-world.cc位于https://github.com/google/mediapipe/blob/master/mediapipe/examples/desktop/hello_world/hello_world.cc

这个hello-world文件，包含了所有框架运行，需要的组件。

graph是怎么运行起来的？

准备config文件
根据config文件，初始化graph
graph初始化，调用Initialize
创建输出读取 OutputStreamPoller
graph开始运行
给graph添加输入
流程结束，进入关闭状态
读取输出
等待graph结束

main

CalculatorGraph graph

graph.Initialize(config)

OutputStreamPoller poller = graph.AddOutputStreamPoller('out')

graph.StartRun({})

graph.AddPacketToInputStream

graph.CloseInputStream('in')

poller.Next(&packet)

graph.WaitUntilDone()

CalculatorGraph::Initialize

validated_graph->Initialize()

Initialize

CalculatorGraph::InitializeExecutors

CalculatorGraph::InitializePacketGeneratorGraph

CalculatorGraph::InitializeStreams

CalculatorGraph::InitializeCalculatorNodes

CalculatorGraph::AddOutputStreamPoller

CalculatorGraph::StartRun

CalculatorGraph::PrepareForRun

Scheduler::Start

CalculatorGraph::AddPacketToInputStreamInternal

CalculatorGraph::CloseInputStream

OutputStreamPoller::Next

CalculatorGraph::WaitUntilDone