[FFmpeg-user] write output of find_rect to a file?

[Michael Koch]

Hi Moritz,

>
>> Hello,
>>
>> I want to track an object and need the x,y coordinates of this object
>> for each frame.
>> Is it possible to write the output of the find_rect filter to a file?
> I don't have any good command line for find_rect handy, but it should
> work with something like this (untested, of course):
>
> $ ffprobe -f lavfi -i movie=input.mp4,find_rect=options -show_entries frame=pkt_pts_time:frame_tags=lavfi.rect.w,lavfi.rect.h,lavfi.rect.x,lavfi.rect.y -of csv

The above command works fine, but is it possible to print the number of 
the frame instead of the timestamp?
I did search the documentation for a list of variables, but didn't find 
any. Also "pkt_pts_time" seems to be undocumented.

Michael