Introducing Google AI Edge Portal : Benchmark Edge AI at scale. Sign-up to request access during private preview.

Hello World! in C++

Ensure you have a working version of MediaPipe Framework. See installation instructions .

To run the hello world example:

 $  
git  
clone  
https://github.com/google/mediapipe.git
$  
 cd 
  
mediapipe

$  
 export 
  
 GLOG_logtostderr 
 = 
 1 
 # Need bazel flag 'MEDIAPIPE_DISABLE_GPU=1' as desktop GPU is not supported currently. 
$  
bazel  
run  
--define  
 MEDIAPIPE_DISABLE_GPU 
 = 
 1 
  
 \ 
  
mediapipe/examples/desktop/hello_world:hello_world # It should print 10 rows of Hello World! 
 # Hello World! 
 # Hello World! 
 # Hello World! 
 # Hello World! 
 # Hello World! 
 # Hello World! 
 # Hello World! 
 # Hello World! 
 # Hello World! 
 # Hello World!

The hello world example uses a simple MediaPipe graph in the PrintHelloWorld() function, defined in a CalculatorGraphConfig proto.

  absl 
 :: 
 Status 
  
 PrintHelloWorld 
 () 
  
 { 
  
 // Configures a simple graph, which concatenates 2 PassThroughCalculators. 
  
 CalculatorGraphConfig 
  
 config 
  
 = 
  
 ParseTextProtoOrDie<CalculatorGraphConfig> 
 ( 
 R 
 " 
 ( 
 input_stream: "in" 
 output_stream: "out" 
 node { 
 calculator: "PassThroughCalculator" 
 input_stream: "in" 
 output_stream: "out1" 
 } 
 node { 
 calculator: "PassThroughCalculator" 
 input_stream: "out1" 
 output_stream: "out" 
 } 
  
 ) 
 " 
 );

You can visualize this graph using MediaPipe Visualizer by pasting the CalculatorGraphConfig content below into the visualizer. See here for help on the visualizer.

   
input_stream:  
 "in" 
  
output_stream:  
 "out" 
  
node  
 { 
  
calculator:  
 "PassThroughCalculator" 
  
input_stream:  
 "in" 
  
output_stream:  
 "out1" 
  
 } 
  
node  
 { 
  
calculator:  
 "PassThroughCalculator" 
  
input_stream:  
 "out1" 
  
output_stream:  
 "out" 
  
 }

This graph consists of 1 graph input stream ( in ) and 1 graph output stream ( out ), and 2 PassThroughCalculator s connected serially.

hello_world graph

Before running the graph, an OutputStreamPoller object is connected to the output stream in order to later retrieve the graph output, and a graph run is started with StartRun .

  CalculatorGraph 
  
 graph 
 ; 
 MP_RETURN_IF_ERROR 
 ( 
 graph 
 . 
 Initialize 
 ( 
 config 
 )); 
 MP_ASSIGN_OR_RETURN 
 ( 
 OutputStreamPoller 
  
 poller 
 , 
  
 graph 
 . 
 AddOutputStreamPoller 
 ( 
 "out" 
 )); 
 MP_RETURN_IF_ERROR 
 ( 
 graph 
 . 
 StartRun 
 ({}));

The example then creates 10 packets (each packet contains a string "Hello World!" with Timestamp values ranging from 0, 1, ... 9) using the MakePacket function, adds each packet into the graph through the in input stream, and finally closes the input stream to finish the graph run.

  for 
  
 ( 
 int 
  
 i 
  
 = 
  
 0 
 ; 
  
 i 
 < 
 10 
 ; 
  
 ++ 
 i 
 ) 
  
 { 
  
 MP_RETURN_IF_ERROR 
 ( 
 graph 
 . 
 AddPacketToInputStream 
 ( 
 "in" 
 , 
  
 MakePacket<std 
 :: 
 string 
> ( 
 "Hello World!" 
 ). 
 At 
 ( 
 Timestamp 
 ( 
 i 
 )))); 
 } 
 MP_RETURN_IF_ERROR 
 ( 
 graph 
 . 
 CloseInputStream 
 ( 
 "in" 
 ));

Through the OutputStreamPoller object the example then retrieves all 10 packets from the output stream, gets the string content out of each packet and prints it to the output log.

  mediapipe 
 :: 
 Packet 
  
 packet 
 ; 
 while 
  
 ( 
 poller 
 . 
 Next 
 ( 
& packet 
 )) 
  
 { 
  
 LOG 
 ( 
 INFO 
 ) 
 << 
 packet 
 . 
 Get<string> 
 (); 
 }

Hello World! in C++ Stay organized with collections Save and categorize content based on your preferences.

Hello World! in C++