If you crop the video, then the subtitle offset (forced position) is completely ignored. This is really frustrating because the subtitles are then cut off.
For example, I am trying to watch Quiz Show. The movie is widescreen, but it is old, so when they made the DVD, they made it fullscreen. That is, the picture itself is 16:9, but it has black bars above and below it to fill it out to 4:3. This is annoying because it makes the video smaller than it should be (figure 1). Normally, I would crop the video so that it fills the window, but unfortunately that also cuts off the subtitles (figure 2).
What’s of particular note is that if I try to use VLC’s built-in screen-capture function, it momentarily moves the subtitles up so that they appear properly in the screenshot, but then moves them back down so that they are not visible when the video resumes.
Not that I should have to, but I did try messing around with the subtitle position, but it only had an effect when the video was un-cropped. As soon as I cropped it, the subtitles fell back down below the video (to position 0) and were cut off.
If you fix this other problem, then this one becomes less of a problem, though it is still a bug.
Figure 1: Old movie when played fullscreen normally
Figure 2: Same movie when cropped to fill screen; subtitles are cut off