[XviD-devel] help me please (about setedges() and others)

[Nicola Bicocchi]

Hi all,
  i'm playing with xvid in my thesis and i don't understand some things:

1) in encoder creation: 
  pEnc->mbParam.edged_width = 16 * pEnc->mbParam.mb_width + 2 * EDGE_SIZE;
  pEnc->mbParam.edged_height = 16 * pEnc->mbParam.mb_height + 2 * EDGE_SIZE;

why edged_width and height are so big ?
which is the function of the extra memory allocated ?
i don't understand the function image_setedges() called in FrameCodeP. what does it do ?

2) i would like to store videos recorded by a fixed camera.
in these videos background stands still and moving objects are quite little.
in your opinion are there big problems if i would like to code not the whole frame
but just a part of it (a rectangular region) ??

thank you in advance
Nicola