The crop filter does not support timeline editing but the overlay filter does.
Given that you have " a file that contains the cropping rectangle's X, Y, Width, & Height for each frame", you can use the filter_script option to do this in FFmpeg.
Having said all that, if i were to have an option of having access to the software that is able to work on images frame by frame, i would go that route. You can then do min(max(n,200)-200, 150)įor the frames <200, max(n,200) would generate 200, then we take away 200 to make it 0, and then min will return the first part up until 350 frame, where that result would become more than 150 and the constant will begin to be returned.Īlthough writing such formula by hand would be quite tedious, maybe it will be helpful in some cases as well. So let's imagine that you want to move 1 pixel per frame, but only from 200 to 350 frame. Keep in mind that there are quite a lot of math functions that are provided by the filter interface of avconv (and i'm sure ffmpeg is similar). In here i'm moving 1 pixel per frame, which is very unlikely how somebody would move. You could do something along the lines of: avconv -i input.ogv -vf 'crop=200:100:n:n' -c:v libtheora output.ogv Let's assume, for example, that the speaker is moving from top-left to bottom-right in the picture. This means that if the the speaker moves in a predictable way you could theoretically do that without an external application.
You can have a moving crop if you can create some sort of formula between the frame number and the position of the crop but there are no analytic tools available to do that. I have already changed to avconv, so i apologise if the answer may be a little different in the classic ffmpeg, but i believe that not much difference should be there.
0 kommentar(er)
