OpenCV How to run two videos at same speed?

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He Hello guys, how to make two video run at same time and same fps ?

VideoCapture capture("../video/Success/NT 1.1.wmv");
VideoCapture capture2("../video/Success/NT 1.wmv");

capture.set(CV_CAP_PROP_FPS , 30);
capture2.set(CV_CAP_PROP_FPS , 60);

For example, i have this two video and i set the fps for them already but it doesn't work for my program..