TV Episode in DIVX different aspect ratio from original broadcast

[gromit60]

When I watch a widescreen TV broadcast on my digital widescreen TV, the picture completely fills the screen. When I buy a commercially produced DVD with that particular show on it, that too correctly fills the screen. But when I download the same show, encoded as a DIVX file, from the Internet, burn it as a data file to a DVD and play it, there are black bars top and bottom, just as if it were a widescreen movie. And nothing I do, (save changing the TV display to a Zoom mode but then I lose material at the left and right sides of the picture) can make the picture fill the screen.

Can anyone please explain why my DIVX files can't appear just like the original broadcast or commercial DVDs of the same material? I'm completely baffled.

[guns1inger]

The most likely explanations are :

1. The person who capped and encoded the show has cropped it for whatever reason.

2. You don't have you Divx player set up correctly.

Simplest way if to look at the resolution and find out what the aspect ratio of the divx file is. If it is wider than 1.778:1, you will get black bars.

[Krispy Kritter]

A third explanation:

3. Recording a HD broadcast on a non HD device. For example, when I record HD broadcasts on my Tivo 2 DVR (non HD unit), I get a widescreen image with black bars top and bottom because it is recording in 4:3.

[gromit60]

Thanks. I'm pretty sure it's not my new Denon 1730 DVD Player output settings because I've tried them all. Could it be that the DIVX part of the firmware in the DVD player can't handle the AVI files properly?


How do I determine the Aspect ratio - do I derive this from the pixel format of the AVI file? If so, can you confirm that I have calculated the following correctly:

720x400 avi = 1.85 ratio
608x320 = 1.9
640x352 =1.82
640 x464 = 1.38

Thanks for your help.


EDIT - Have just seen Krispy Kritter's reply. I think this is likely to be the reason for my problems but would be grateful if you could confirm the above.

EDIT - Have just seen Krispy Kritter's reply

[jagabo]

If MPEG4Modifier tells you the pixel aspect ratio is 1:1 (square pixels) then the DAR is the ratio of the frame size. Of course, the original encoder may have screwed up so that may not be right either. In such a case you have to eyeball the DAR. Find something with a known shape (a ball, a tired vied straight from the side) and adjust the DAR until it's the right shape.

Some players will respect the MPEG4 DAR flag so you may not need to reencode. You can use MPEG4Modifier to set a new DAR and save as a new file.

DAR = SAR * PAR

DAR = Display Aspect Ratio the AR of the final picture
SAR = Storage Aspect Ratio (the frame size)
PAR = Pixel Aspect Ratio (shape of each pixel)

[guns1inger]

3. Recording a HD broadcast on a non HD device. For example, when I record HD broadcasts on my Tivo 2 DVR (non HD unit), I get a widescreen image with black bars top and bottom because it is recording in 4:3.

However, once the the black bars are cropped, the image should still be 16:9, just not anamorphic (which is fine for conversion to a 1:1 PAR format)