[MPlayer-users] Cropping in original-size vs reduced-size

[Jorge Fábregas]

On Friday 23 March 2007 8:09 am, Nico Sabbi wrote:
> why don't you crop before rescaling?

I do. I was just talking hypothetically just to show my point.

> something like
> crop=704:480:8:0,scale=608:-10,expand=640:480

Why would I crop black bands in order to have them back (using the expand 
option)?

The problem I'm having is:

1- If I crop based on original frame size and I my target resolution is 
640:480, the actual footage will not be 4:3. Let me make this clear:

It's not the same to crop and scale than to scale and crop.  I know the first 
one is the way to go but I just don't know how to end up with the proper size 
if I downscale to 640x480 for example.

2- (hypothetically speaking). If I scale to 640:480 I'm actually getting 4:3 
(and the image looks as it should AR-wise) but then I have black bands on 
sides that I want to get rid of.

Basically, I want to downscale but I'm not sure if for proper downscaling you 
should consider the original frame size (720x480 with black bands on sides) 
or if you need to just consider the actual contentent (cropped).  I tend to 
think is the first one..since that's the way the signal is sent ot the TV 
when I play the DVD on my TV.

Jorge