>I want to convert to 668x480 4:3 mpeg video stream after the 2nd step
^^^
>padding. So, the PAR of such (destination) DVD video stream with 4:3 aspect
>ratio (DARd=4/3) is:
>
> width=668
> height=480
>
> PARd=$height*4/3/$width=0.958084
>
>Now determine the zoom size for the 1st step:
>
> height = (PARd * width ) / DARs = (0.958084 * 668 ) / (4/3) = 480
>
>This does not make sense to me, the calculated height should be smaller
>than 480, shouldn't it? Please see where did I go wrong.
You explicitly set up your destination PAR to get a 668x480 frame, so of
course you ended up with a height of 480. (:
Assuming you want a 4:3 video with a width of 668 and a PAR of 1:1 (as in
typical AVI video streams), you should use example 3 and set the width to
668, which will give you:
width = 668
height = (PAR * width) / DAR = (1/1 * 668) / (4/3) = 501
As noted in example 4, however, odd heights cause problems for standard
video codecs, so you'll need to change the height to either 500 or 502.
(Also, width and height values not divisible by 16 cause a slight increase
in bitrate, or loss of quality at a given bitrate.)
--Andrew Church
[EMAIL PROTECTED]
http://achurch.org/
