Qt Multimedia loading time

[angeFran]

Hi everybody,
while developing a multimedia reader with QT Multimedia framework under Windows 10, I have noticed that some video formats (especially .MTS and .MOV) spend a long time in "loading" state, up to 10-15 seconds for a 30 seconds long video.
My question is NOT about reducing loading time.
I'd like to know if there is a mechanism to estimate the progress of the loading so that I can display it in a progress bar.
My backend id DirectShow; (I had too hard time trying to use WMF).

Thank you!