Aspect ratio off

[pdbowling]

Good day.
I've ripped a number a DVDs and I've run across something odd.

Normally, DGIndex demuxes and VirtualDubMod can save the remuxed file in whatever format.
When you open the file in VDubMod, it shows as the normal aspect ratio assigned to it by the source.

What I've discovered, is a video source that is 640x480 that opens in VDubMod as 352x480. Normally, I wouldn't bother but when I run the
resize() filter on the footage, I get VERTICAL visual striping. Deinterlacing fixes the horizontal, but I have no idea what's causing the source to open as 352x480 instead of its normal aspect ratio. The stretching during the
resize is of course Causing the striping, but does anybody know why it's coming in squished left to right in the first place? or how to fix it if possible?

Thanks everyone.

[unskinnyboy]

What kind of source is this? 640x480 doesn't sound like a DVD, is it an avi? Can you provide a sample?

[neuron2]

Yes, please provide an *unprocessed* source clip.

How do you know it is 640x480 if it opens as 352x480?

[pdbowling]

Oh, I'm sorry. I should have said before.

The story goes....
We edited a movie and made a rough cut dvd from Adobe Premiere. The hard drive crashed and all we had left of the movie was the dvd we made. It's 4:3 with black bars top and bottom. 640x480 makes everyone look proportional rather than tall and skinny. That was the export size from adobe. The black bars make up a good portion of the 480 but it's not quite letter boxed all the way out to be like 35mm film.

It was shot on a dvc pro camera.

I would love to post a sample. Please excuse my lack of knowledge but how would I go about doing that?

So to summarize:
VOB files on a homemade DVD. The natural aspect with black top and bottom bars is 640x480. VDubMod opens the raw VOB file but it opens at 352x480 and muxes fine with audio but the resizing back to 640 causes the vertical striping (very similar to the horizontal striping seen with interlacing).

Hope I gave you enough info.
PB

[pdbowling]

Well, chalk one up to inexperience. The resize function has many parameters dictating what type of resizing to do. I still don't know why it opens at 352x480 but using a bilinear resize rather than nearest neighbor resize smooths out the vertical stripes. Hey, I hope this helps someone else that might run across the issue. Thanks everyone.
PB

[unskinnyboy]

Glad to know your vertical "striping" issue is solved, but I am still curious about the resolution issue. If the resolution of the raw VOB is 640x480 (which in itself is a weird resolution for a DVD), then VirtualDubMoD _must_ open it as 640x480. Are you sure you are not resizing it to 352x480 (d2v in avs) and _then_ opening in VirtualDubMoD (you did mention that you are opening the raw VOB, but still..)?

If you don't mind, please cut a sample of the VOB using ChopperXP (http://www.digital-miner.com/software/chopperxp.zip) and upload it to any of the file hosting sites mentioned in this (http://forum.doom9.org/showthread.php?t=96362) thread. I'd like to have a look. Thanks.

[neuron2]

Yeah, I'm curious about it too. Since it appears to make no sense, it's probably in your interests to try to understand it. You may be using a wrong process.

[pdbowling]

Hi,
Thanks for the suggestions. I posted a sample here. http://sr2.mytempdir.com/82674
When I used ChopperXp to play it, an odd thing happened. I opened the clip in Chopper and it opened at the correct aspect ratio. Then I went back to my source VOB and opened it in Chopper. It opened wrong. When I went back to the sample, it opened wrong.... Made no sense to me. Thanks
PB

[unskinnyboy]

OK, got it.

See the screenshot of the sample opened in GSpot:

http://img283.imageshack.us/img283/289/gspot9ij.jpg

The frame resolution of the VOB is indeed 352x480. But your MPEG-2 stream header has a SDE (Sequence Display Extension) value of 720x480 (NTSC DVD frame size) embedded into it (put by the encoder). This value is to increase compatibility with some DVD/Video editing applications and should be *ignored* by the DVD players - which means your DVD player should play this as 352x480 and not 720x480 (unless you got a buggy Pioneer - some models of Pioneer are known to read the SDE values and display the DVD in an incorrect aspect ratio. This can be worrying for a Pioneer DVD player owner because the encoder can put any value in the SDE field and the player will fall for the bogus value).

So outside of Adobe Premiere, this SDE value is irrelevant and it is 352x480 itself. Btw, it is 720x480 and not 640x480.

[pdbowling]

Interesting...
That is quite a handy software, too. I may do a search for it and download it. Just because I think the 352 aspect ratio looks stupid, I'll go ahead and re-encode it. Thanks for the heads up on the actual aspect ratio.

PB

[ottermi619]

it is 720x480 and not 640x480.
In a way, I understand why 640 and not 720 by 480 was mentioned. If you were to leave the scanline (480) resolution alone, and to put the horizontal resolution into 640, you would get a 1.33:1 picture. 720×480 and square pixels allows for a 1.5:1 aspect ratio.
Apparently, according to Google search results for "352x480 dvd" it is a standard DVD resolution, but I don't even know if I have any dvds encoded in 352×480. Could be an anamorphic resolution. With square pixels, 352×480 allows a .73:1 aspect, though with 240 lines, it is 1.46:1

[LocalH]

None of these are square pixels though, except for 640x480 (and by extension 320x240). They're all 4:3 DAR, but with different PARs. If you want to take either 352x240 or 640x480 and make it into DVD-compliant 4:3 video, you have to resize to 704x480 and then pad with black to 720x480.