Can VLC crop black borders on the fly?

Many recordings have black bars either on top and bottom or at the left and right side due to the various aspect ratios used, resulting in a 4:3 coded 16:9 movie showing black borders on all four sides in fullscreen mode on a 16:9 monitor (top and bottom because of the movie, left and right because VLC doesn't know they are superflous and that 4:3 has to be fit on the 16:9 screen). Cropping the black bars with AviDemux would require a recoding.

Is it possible instead to let VLC display only the borderless part of the video?

I.e. somehow provide a config file or initially choose a "zoom" section.

Bonus question: I'll award a bounty of 100 rep for any automatic on-the-fly border detection and removal solution, be it VLC or other means, as long as it's free.

If you press C it will toggle through the crop ratios and may help you with eliminating the black bars.

Well, I should have checked VLC's Video menu as I did while posting this question... There's the crop to 16:9 option I was looking for... Anyway, if you find an automatic cropping estimation method, the bounty will still be there.

Simply go to VLC Player preferences > Video (you must be in "All" mode, not "Simple" mode). On the right-hand side, scroll down to "Video cropping" and type in either "16:10", "16:9", or "4:3", depending on what your screen's aspect ratio is. Press the Save button at the bottom.

If black lines remain, then they are actually part of the video as opposed to just an empty section of the screen. In this case, adjusting manually is the only logical option left.

Select 'tools', go to preferences, select 'Crop', and control the width and height of the frame until the bars are gone.