[MPlayer-users] General video question so as to understand movie aspect

[RC]

On Wed, 06 Sep 2006 07:23:25 +1200
Phil Bertram <phil.bertram at clear.net.nz> wrote:

> Am I correct to assume that after I crop off the black bars and thus
> have a movie that is 16/9 shape (crop=688:416:16:80), the movie is
> still has an  aspect of 4/3 and so aspect I should use -aspect 4/3
> when encoding with mencoder.

-aspect only affects the input, not the output.  For the output, you use
"-lavcopts aspect=" to specify the aspect, or preferably  "-lavcopts
autoaspect" to have it automatically calculate the proper aspect for
you.

The aspect of your output file will/should certainly not be 4/3. 
Croping, scaling, etc., changes the aspect ratio, and a new aspect has
to be calculated.