[FFmpeg-user] flatten f4v append with different resolution

[Madovsky]

Hi,

I'm trying to convert a long F4V recorded on FMS
with multiple "append" from a livestream. some
segments contains different resolutions than the one that started.
I started from 462x260, after 1920x1200 etc...
from flash player the stream works correctly, shows every segements.
from a third party video player, the hig resolution is not shown or only
a part of it with big pixel traces.
I tried to flatten the file with f4vpp which solve the width and height 
of the
smaller segment but the high resolution is cropped
I tried to find a way to resize with ffmpeg but no success.
is it possible to let fffmpeg resize at a certain part of the movie?

thanks