>> Going back to your 640x480 example, I think I may not be entirely clear on
>> what you're trying to do. Are you trying to do the opposite of Example 6,
>> i.e. take a letterboxed 4:3 video stream and convert it back to the
>> original 16:9 format?
>
>Yes, yes, by doing the exercise, I can make sure I understand everything,
>and also make sure every bit and piece fit nicely together.
In that case, the part that you were misunderstanding was the calculation
of the output video frame width and height. The formulas in Examples 3-6
are for when you don't know what the proper frame size is. Even in
Example 5, where the output is going to DVD and the frame size is known
ahead of time (720x480), the calculations are required to produce an
_intermediate_ frame, which then has borders added to it.
In your case, you have already removed the black borders, giving you a
640x360 frame with a 16:9 DAR (that part of your logic is correct).
Since the 720x576 DVD frame you are converting to also has a 16:9 DAR,
you can just zoom the frame directly to that size, and you're done.
If you want to apply the formulas to ensure that you have the correct
size, you have to use the proper PAR. If you compute the PAR of a
720x576 video stream with a 16:9 DAR using the method shown in Example 5,
then use that PAR in the formulas to compute width and height, you should
find that you get the proper values.
--Andrew Church
[EMAIL PROTECTED]
http://achurch.org/
