[FFmpeg-devel] [PATCH][RFC] variable frame sizes

[Eric Buehl]

I see...

This brings up an interesting question:  what should cropping do in the
event of a frame size change?  Here are some options I see:

1: Blindly keep cropping the same absolute values.  This will require
re-checking of crop boundaries to ensure we can't over-crop as is done in
opt_frame_crop_top, opt_frame_crop_bottom, etc and may result in erroring
out mid-encode.

2: Scale of the crop values based on the amount of change from the previous
frame size.  This would be as if all frames were first pre-scaled to a
normalized size, then cropped, then scaled again to their output frame size.

I would tend to vote for the latter approach since it should never error out
and will result in visually consistent cropping in the output.  This would
also require scaling padding in the same way.

What do you think?

Eric