authoring DVD - pixel-aspect-ratio problem

[Levina]

I have an avi file [DivX]. I want to author a DVD, but I just can't get the aspect ratio right. The avi file is 640 x 272. I have tried just about everything in ffmpegX but all come out stretched (everything and everybody is long and thin). I have tried DVD 16:9, 16:9, 2:35:1 and it won't come out right. All stretched. Now with VLC I can correct this but not my Mac's DVD Player or my stand alone dvd player. The (selectable) subs are also way too high in the frame (which of course is not a problem, I can change it's settings, but it's just to show that the aspect ratio is way off). Anybody have any ideas as how to solve this? Thanks in advance.

[jagabo]

Resize the 640x272 frame to 720x436. Add 70 pixel wide borders to the top and bottom to bring the frame size up to 720x576. Encoded as 16:9 MPEG2.

[Levina]

Thanks jagabo. Right, resizing the frame. How do I do that? I'm so sorry, but I have never done this and looked here and there but really haven't got a clue.

[Case]

To get a 2.35:1 movie in a 16:9 frame, you'll be using 75% of the available height, and 25% of the height as letterbox bars: 12.5% above and 12.5% below.
A PAL DVD then would have a height of 72 + 432 + 72 = 576 px. (2 pixels more or less is hardly noticeable )
An NTSC DVD then would have a height of 60 + 360 + 60 = 480 px.

To use this in ffmpegX, go to the Video tab, set the required Framerate, set Autosize to DVD 16:9, change the Video Size height to the calculated number (in that order, as Autosize also changes the Video Size field based on the Framerate).
Next, go to the Filters tab, in Image filters, set the Letterbox values (top, bottom, left, right).

[Levina]

All right!! My avi file is now a DVD with the right aspect ratio. Case and jagabo: thank you very much.

[jagabo]

Glad to hear you got it working. I don't use ffmpegX so I could only give general instructions. Fortunately, Case stepped in with the details.