This forum is disabled, please visit https://forum.opencv.org
 | 1 | initial version |
Hi dmcenan!
This works thanks to the magic of OOP (Object Oriented Programming), you can checkout the source code of highgui/src/cap.cpp where the overloaded >> is implemented (as you observed) and if you follow the track of that overloaded method you will reach the file highgui/src/cap_ffmpeg_impl.hpp which implements the method:
CvCapture_FFMPEG::grabFrame()
That method is in charge of grabbing a frame from a video file source, and at some point after some checks and decodification stuff, there is a wonderful
frame_number++
Which causes the VideoCapture object give you the next frame on the video stream the next time you call cap >> frame
I hope this helps.