>Please forgive my dense, I still don't understand it.
>
>in Example 4, after clipping with -j, the 16:9 video is still considered
>to be 16:9. I think that make sense, you can arbitrarily clip the video
>into any weird shapes (even tall), but 16:9 still hold. I.e. whatever left,
>will still play fine, without distortion.
Oops! This is totally wrong, and you'll end up with a (slightly) stretched
video if you try it. I have no idea what I was thinking when I wrote that.
I've removed that section, and clarified the change in DAR; sorry about the
confusion!
>Now suppose this 640x480 @ 4:3 video is handed over to me by somebody else.
>I don't know how he come up with it, whether it was from 16:9 source, or
>4:3 or 1:1, as long as it plays fine in movie players, or on TV, It is
>true 4:3. Otherwise, there will be distortion.
If you're planning to store the video in a video file and give it to
others, you would of course want to give thought to things like
--export_asr. The example is only intended to illustrate the specific
example of a display device with a fixed size and PAR.
>> In fact, since DVD players adjust their PAR to
>> match the video's frame size and DAR, there is no need to perform these
>> calculations at all; you just need to resize the video to the proper DVD
>> frame size with -Z and use the proper --export_asr code, as in Example
>> 2.
>
>Again, I'm lost here. What is the condition that there is no need to
>perform these calculations? any arbitrary video, eg 672x272 one?
The calculations are only necessary when you don't know what final frame
size you want. In the case of DVD video (the second step of Examples 5
and 6), the final frame size is fixed, so there's no need to try and
calculate it.
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?
--Andrew Church
[EMAIL PROTECTED]
http://achurch.org/
