Video Resolution

[Kevin Buckelew]

Hello, this is my first time posting on this message board, though I've read it quite a bit since becoming interested in video. I have a problem, and please forgive me if the question sounds stupid, I'm still fairly new to all of this.

My footage, recorded on a Canon GL2, is 720x480. In the original footage, the frame size looks basically square. When I export a finished video from Premiere in Microsoft DV AVI form, it stays this same size. When I export in any compressed form, though, it stretches the picture out horizontally, even when it is exported at the original resolution. It would seem that the original footage is not actually a 4:3 ratio, but the compressed output video is, which causes it to stretch. I was wondering if there is any way to fix this and make the compressed output closer to the original "square" size of the frame.

Thank you,

Kevin Buckelew

edit: eep, I'm sorry for posting in the wrong forum.

[Mike Rehmus]

I think you have a setting wrong either in your NLE or in your display device.

SD video is normally 4:3. It sounds like your system is attempting to display it at an expected 16:9 by stretching it horizonally.

I don't understand what you mean by 'compressed form.' DV by definition is compressed. Do you mean something like MPEG?

[Rob Lohman]

What you are probably running into is pixel aspect ratio. NTSC
4:3 DV has an aspect ratio of 0.9. So your resolution of 720x480
is actually played back (if done correctly) at 648x480!

Now MPEG(2) has the same pixel aspect but I do think Windows
Media Player does NOT play it back correctly (you can more easily
see this with SVCD's). Open your MPEG in a software DVD player
to see it correctly.

Are you going to DVD? Then you should watch the final product
on a TV and/or in a software DVD player. Not in WMP for example.

Anyway, this might not be what you are talking about as Mike
also expressed. Can you be a bit more specific?

[Kevin Buckelew]

When I said compressed, I meant into anything other than the original DV form (in my case, I tried it in Quicktime and Windows Media compressed AVI). I don't think it's stretching it out to 16:9 though, it just seems that the 4:3 differs between the two, and I'm not sure why. I definitely exported it at 4:3. The original footage does not look like it's 720x480, that's what is confusing to me. 720x480 would be a noticeably rectangular shape, but the original footage looks completely square. I don't understand this because I'm positive that they are both supposed to be the same resolution.

[Kevin Buckelew]

I replied before seeing your post, Rob. That would explain it. Unfortunately, I can't really control how the file is viewed because it's for the web (which is why I was compressing it). I guess I'll have to cope with it. Thank you both very much for the help.

[Rob Lohman]

Where is this 16:9 in your last post coming from? I'm a bit confused
as to what you are getting at. I explained earlier that you are
getting 648x480 which is square on a 4:3 monitor. I'm just not
sure what happens after this in your case. If you can host some
screenshots that might help. Otherwise you can e-mail them to
me as well.

[Kevin Buckelew]

The 16:9 was responding to Mike Rehmus, who said that it might be stretching it from 4:3 to 16:9.

After taking some screenshots, it would appear that it's actually stretching it from 720x480 to 760x480, even though I'm exporting it as 720x480.

The original correct 4:3 ratio:
http://www.kevinbuckelew.com/original.jpg

And then the stretched one after compressing it with Windows Media:
http://www.kevinbuckelew.com/wmcompressed.jpg

When I was looking at it before, I thought it was more of a difference because the original DV footage displayed as basically a perfect square on my windows media player (which means it must have been making it less wide than it was supposed to be), but this (first) screenshot came from Premiere so it's the correct 4:3 ratio.

[Rob Lohman]

What project settings do you have? Can you tell us the exact
(ALL) settings you did for the WM export?

[Kevin Buckelew]

Well, I feel stupid now. Looking at the settings just now I realized I had chosen the seemingly logical "D1/DV NTSC (0.9)" pixel aspect ratio, and the "Square Pixels (1.0)" setting solved the problem. It's probably more complicated than that, but for now it seems to have worked. Thank you very much for your help, I really appreciate it.

[Rob Lohman]

When exporting you should use 1.0 pixel aspect ratio indeed
(for things like WM or QuickTime) since computer screens are 1.0
PA. If you where to export to MPEG2 for DVD authoring you would
still use 0.9 since DVD's are meant to be played on TV's etc.

Glad you solved your issue!