λvue SDK User Manual
λvue Sample GUI User Manual
API reference
Download

In this lesson, we demonstrate how to magnify a video file using default settings with MagEngine .

Program 

#include <QCoreApplication>
#include <iostream>
#include <unistd.h>
/* Include the main Lambda SDK header file */
#include <MagEngineAPI.h>

using namespace std;
using namespace geko;

bool run_engine = true;

/* Callback function to handle various Lambda events */
void cbFunction(struct EventValue value) {
  switch(value.event) {
    case OPEN_FILE_SUCCESS:
      cout << "File " << getSourceName() << " opened, processing ..." << endl;
      break;
    case OPEN_FILE_FAIL:
      cout << "File open failed" << endl;
      run_engine = false;
      break;
    case END_OF_FILE:
      cout << "Process completed" << endl;
      run_engine = false;
      break;
    default:
      break;
  }
}

int main(int argc, char *argv[])
{
  QCoreApplication a(argc, argv);

  /* Display the current Lambda SDK version */
  cout << "Hello World, I am using Lambda SDK verson: "
       << MAG_ENGINE_VERSION() << endl;

  /* Initilize Lambda engine using defined Callback function as parameter
   * and return the license status (See SDK manual for states)
   */
  enum LicenseResponse license_status = initMagEngine(cbFunction);

  /* Check the license state, continue only if the license is valid */
  cout << "Lambda license status: " << license_status << endl;
  if (license_status <= 0) {
    cout << "Valid license" << endl;
    setFileOutput(RECORD_PROCESSED_ONLY);
    char video_source[] = "C:/Programming/baby.mp4";
    setSource(OPEN_FILE_SOURCE, video_source);
    /* Loop to control when to stop the Lambda engine */
    while (run_engine) {
      sleep(1);
    }
  } else {
    cout << "Invalid license" << endl;
  }

  /* Destroy Lambda Engine before exiting the program */
  destroyMagEngine();

  return a.exec();
}

You can download the testing video baby.mp4 here .

Line-by-line Explanation 

#include <unistd.h>

Include the standard POSIX header file so we can have access to usleep function. 

bool run_engine = true;

Boolean variabled added so we can control when to terminate the application. 

setFileOutput(RECORD_PROCESSED_ONLY);

Set the engine output mode to RECORD_PROCESSED_ONLY (Default is RECORD_NONE . For complete description of modes, please refer to the λ·vue SDK API Manual). This instruct MagEngine to save the processed video to a file. 

char video_source[] = "C:/Programming/baby.mp4";
setSource(OPEN_FILE_SOURCE, video_source);

Specify the source video file to process. Function setSource() instruct MagEngine to open the specified file AND immideiate start the magnification process. 

switch(value.event) {
  case OPEN_FILE_SUCCESS:
    cout << "File " << getSourceName() << " opened, processing ..." << endl;
    break;
  case OPEN_FILE_FAIL:
    cout << "File open failed" << endl;
    run_engine = false;
    break;
  case END_OF_FILE:
    cout << "Process completed" << endl;
    run_engine = false;
    break;
  default:
    break;
}

Switch statement added to handle MagEngine events. In this lesson, we only handle events related to setSource() , namely:

  • OPEN_FILE_SUCCESS: event generated when the source file has been successfully opened by MagEngine

  • OPEN_FILE_FAIL: event generated when MagEngine failed to open the specified source file. Boolean variable run_engine is set to false to terminate MagEngine after file read error.

  • END_OF_FILE: event generated when end of file reached while reading source video file. Boolean variable run_engine is set to false to terminate MagEngine after video magnification is completed for the specified file. 

while (run_engine) {
  usleep(100);
}

Loop to prevent program from terminating before desired break point. In this lesson, the break point is after the specified video has been processed or when MagEngine failed to open the specified file.

Program Output

When you run this program, you should get the following console output and the output video file under C:/Programming directory named baby_TIMESTAMP_processed.avi which you can then open with any video player to view the result.

Lesson2Output
Figure 1. Lesson 1 Output