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Old May 5th, 2003, 10:14 AM   #1
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720x480 vs. 856x480

Hello all.
I've shot some footage with the xl1s in widescreen mode and I downloaded it to premiere. I'm wondering, why is it that in After Effects and in Premiere, when you interpret the footage, or when you export the footage out of Premiere, the only pixel size to do so is 720x480? I don't understand this, because it is clear that that dimensions of my source footage are 856x480.

Isn't 720x480 just regular 4:3 with rectangular pixels? I'm so confused here. I just want to create a composition in After Effects, but when I set my composition to widescreen (which is what I shot) then it defaults to 720x480. Anyone know why?

Another example, in AE, a couple of choices are

NTSC DV (720x480)
NTSC DV WIDESCREEN (720x480)

Why are they the same size???

If I'm not making any sense let me know and I'll try to rephrase it. thanks in advance.
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Old May 5th, 2003, 10:27 AM   #2
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I work with 16:9 also, and it's correct that the image size is 720x480, however it's been anamorphically "squeezed" (anamorphic = "form has been changed"). Other than PAL, I think that DV by definition must be 720x480.

When I do the math, using square pixels I get 853x480, which is close to your 856x480. But I'm quite sure that the XL-1s is not creating DV at any size other than 720x480, it's just the pixel aspect ratio which has changed. A widescreen TV would correctly recognize and rescale your footage. If you want to show the footage on a computer monitor you would need to resize it accordingly (I do this with QuickTime myself to show 16:9 on my PowerBook). To view on a standard TV you would need to letterbox it.

I don't know AE, so I can't comment on that however most software allows you to flag your footage as anamorphic 16:9 somehow. If you're doing effects in some other program you generally have to do them at 853x480 then squash to 720x480 unless the software allows you to control the pixel aspect ratio.
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Old May 5th, 2003, 10:52 AM   #3
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ahhhhh ok. That explains some things.
Thanks Boyd. I'm still a little confused though...(if someone else know's AE feel free to chime in).


In AE, when I go to create a composition, if I choose the widescreen comp, then it sets it automatically to 720x480. Then, when I take my footage (interpreted as widescreen footage), and if I place that widescreen footage in my widescreen comp, I get this.

http://www.fusionarena.com/forumpost/wide.gif

See how my footage is actually wider than the comp? I'm wondering why, if I tell AE I want a widescreen comp, and if I tell it that it's widescreen footage, why doesn't it create this for me?


Now, if I resize the comp to 856x480, I get this
http://www.fusionarena.com/forumpost/856.gif
Much better, but now that my comp is at 856, I have other problems. How do I get it back to play on NTSC?

Then if I capture my widescreen footage in Premiere, THEN export it out at 720x480, I can create a 720x480 comp in AE, transform it 75% vertically, and I get this...
http://www.fusionarena.com/forumpost/720.gif

This will look great on an NTSC monitor, but now it's screwed for widescreen TV! This is frustrating. Anyone know how I should be doing this? In the end I might just say screw it and shoot 4:3 and crop in post, seems so much easier that way.
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Old May 5th, 2003, 12:25 PM   #4
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Anamorphic widescreen

Brad,

You seem to be doing the right thing here, so I'm a bit surprised you are getting a mismatch between the apparent width of your comp and that of your footage. With AE, setting the comp and footage to both be D1 PAL/NTSC widescreen should work!

Looking more closely at your web links the first one shows not a clip wider than the comp, but a widescreen comp holding a non-widescreen clip (the white rectangle is the comp boundary). So I'd check again that you have interpreted the clip footage correctly - select the clip in the project window, rightclick and and work on that, before placing it in the comp.

You should avoid at all costs resizing your clips or comps to other than 720 x 480 - such changes will have to be undone when you come to render, with a loss of image resolution/quality.

The only exception to this is with non-video applications like Photoshop. These don't undersatnd rectangular pixels, so you need to create your photoshop content at 720x540 (if NTSC), or 768x576 (if PAL), before resizing the image to 720x480/720x576 just before saving it from Photoshop.

PS - remember that AE won't display the clips in widescreen (when you double click on them) unless you select "pixel aspect correction" in the clip window setting menu (the little one on the right)!

Julian
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Old May 5th, 2003, 01:37 PM   #5
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Hi Julian thanks for the response.

A couple of things...
You said "Looking more closely at your web links the first one shows not a clip wider than the comp, but a widescreen comp holding a non-widescreen clip (the white rectangle is the comp boundary). So I'd check again that you have interpreted the clip footage correctly - select the clip in the project window, rightclick and and work on that, before placing it in the comp."


Actually, in that link, the white rectangle is the clip boundry, not the comp boundry. In other words, the footage is larger than the comp size. The comp size is 720x480. The actual footage size is 856x480. I see that size when I look at the clip properties. And if I move around that clip, I can see there is more footage to the left and right than what the comp will allow.

http://www.fusionarena.com/forumpost/wide.gif

So that's why I'm confused here. I didn't resize anything. Basically, my footage is being captured at 856x480 in pixels. I captured in Premiere, and then opened up those captured clips in AE. They are all 856x480, so when I create this widescreen comp in AE, it makes the comp 720x480, and so my footage won't fit in the comp.

Here is another picture.

http://www.fusionarena.com/forumpost/megwide.gif
See how my footage is 856x480? That's the only time it will display correctly. So I'm curious as to why when you set a widescreen comp in AE, it is 720x480? 720x480...isn't that the same exact size that you would work in with 4:3? So why wouldn't 16:9 be different? It seems as if I work on this comp in AE as this ratio, then I can just imput it back into premiere and squeeze it down to fit 4:3, as well as have this larger aspect ratio to fit tv?

I hope I'm making sense here, I think I am confusing myself!

Thanks for the photoshop tip, that is good to know as well. Never knew that. I'm also looking for that pixel aspect correction button, can't find it as of yet but I'll keep looking. That may be the answer. ;)
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Old May 5th, 2003, 01:39 PM   #6
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I'm in PAL country so the math is somewhat different but the below links might give you some guidance the size you should work in when creating computer generated stuff for importing into video (I had a hard time figure it out. I can't say that I fully understand but using a size of 1050 * 576 and then resizing gives perfect 16:9 when viewed on my widescreen TV).


http://www.bbc.co.uk/commissioning/b...turesize.shtml and http://www.mir.com/DMG/aspect.html#reftable
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Old May 5th, 2003, 01:54 PM   #7
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I am assuming that XL1 footage is anamorphic (looks stretched in the viewfinder when it was filmed). This still meanst the actual image size you are working in is 720x480 (for NTSC) ...the same as 4:3 footage ! This is true for letterbox format also it is just the way you deal with it that is different. For widescreen output there is a debate as to which is better - 4:3 with letterbox or 16:9 full height anamorphic.

When you start AFX select the widescreen NTSC DV preset (which you have already done)

All footage should be imported and the it should be 'interpreted' to have widescreen pixel aspect ratio (which you have done).

Your problems are that AFX is not showing the correct pixel ratio ...just go the composition window...<top right>..select menu item 'view options'...pixel aspect ratio correction.......tick the box...all should be well !

In general you should never need to do any resizing if shooting anamorphic footage for anamorphic output as the quality will suffer. Premiere deals with it invisibly but AFX needs a push in the right direction.

Hope this helps...if not email me and I will assist further if I can.

simon

PS: Boyd is correct...the DV spec means that image sizes are set at 720x480 NTSC or 720x576 PAL (notice the extra resolution in PAL). Whatever method you use to make widescreen (anamorphic...letterbox) doesn't change the actual image size. For anamorphic mode only the viewing pixel aspect ratio changes, although I believe that DV can flag this in a subcode somewhere.

PPS Hans,

I've just checked the BBC link you gave....very interesting. I have been involved in loads of stuff for the BBC (the recent freeview "mission impossible" stuff for example) and this is the first I've heard about these new 'magic numbers' 788 and 1050 !(PAL of course)...All artwork that I have ever prepared has been other made at 1024x576 - 768x576 - 720x576. Additionally, all the artwork I have been sent by the BBC before has been these sizes, better have a good read of this. I must have been lucky so far !
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Old May 5th, 2003, 02:18 PM   #8
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ahh...ok I think I am getting the big picture based on all your helpful posts. Thank you Simon, Hans, Julian, and Boyd for all your responses. I see now that I can 'preview' the footage in AE using that method. Now I see the difference as well in the way Premiere and After Effects treat widescreen, you need to tell After Effects to view it differently, but not Premiere.

One small thing I am still curious about...Simon, you said

----------------------
"I am assuming that XL1 footage is anamorphic (looks stretched in the viewfinder when it was filmed). This still meanst the actual image size you are working in is 720x480 (for NTSC) ...the same as 4:3 footage ! This is true for letterbox format also it is just the way you deal with it that is different."
----------------------

Yes it is stretched in the viewfinder, you are correct. However, when I open up my captured widescreen clips in Windows Media Player or anything else, it clearly states that the size is 856x480. I've done nothing to change it. Is this what it should be saying? Just want to make sure I am capturing correctly. Now when I create a comp with just the captured clips, the footage is too large for the widescreen comp. However, if I import the widescreen clips into Premiere, then export at 720x480, THEN I will be able to view the clips in After Effects correctly (if I use the preview mode)

Does this sound right?

Thanks!
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Old May 5th, 2003, 02:40 PM   #9
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Brad,

don't believe what media player tells you about the clips. I have opened some 720x576 (PAL) anamorphic DV footage in media player and it describes it as 768x576 (normal PAL).

import the footage in AFX and see what AFX thinks it is.

I am not quite sure of your workflow...but it should be this..


Set up project in premiere using the NTSC DV widescreen preset (THIS IS IMPORTANT). This has image size of 720x480. Do you capturing. Start AFX....using NTSC DV widescreen project...same image size as before. Import your footage....do your compositing (with or without view aspect ratio correction in AFX)..export as format of your choice - DV or tif sequence (tifs must be 720x480). Import back into premiere...finish edit...export to tape.

I suspect that you have some kind of issue with your initial Premiere project.

Email me the premiere PPJ file if you like.

simon
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Old May 5th, 2003, 03:00 PM   #10
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<<<-- Originally posted by Simon Orange: For widescreen output there is a debate as to which is better - 4:3 with letterbox or 16:9 full height anamorphic. -->>>

Hmm, not sure what you mean by this. Of course one might debate whether it's better to distribute material in letterbox format since the majority of TV sets can't handle real 16:9. But I don't think there's much question about which produces higher quality when viewed on a widescreen TV or computer monitor.

If you letterbox a 16:9 image you end up with an active area of about 720x360 pixels and a 720x60 black stripe above and below. That's about as good as an XL-1s or PD-150 can shoot anyway since they do 16:9 by cropping the image and then stretching anamorphically.

However if the anamorphic 16:9 was shot using a camera with higher resolution widescreen CCD's, or if it comes from a source like a 3d animation program, then the letterboxed version has thrown away about 25% of the available vertical resolution. These images make use of the entire screen area instead of just the 720x360 center section.
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Old May 5th, 2003, 03:07 PM   #11
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Hey guys.
Maybe I should have mentioned this. I use the Canopus DV Storm. Simon, when I look at it in After Effects, it also says my footage is 856x480. I found out that it was doing this because I was capturing form the DVStorm in Premiere, which I guess capures wider horizontal pixels?

See this screenshot in Premiere.
http://www.fusionarena.com/forumpost/canopus.gif

Anyone know why Canopus would capture it at a different pixel ratio? It seems as if it's acutally capturing how it should look - not squished. Capturing 720x480 gives you a squised image, that you have to unsquish. Caputring this way give you the full 856x480....this is why I'm still confused. I see the widescreen perfectly when its viewed at 856x480, yet everyone is saying that its really only 720x480?

Boyd, when choosing between 16:9 or 4:3 on a camera such as the XL1s, isn't the resolution the exact same? In one method you're cropping in post, the other method crops in camera, and you shrink it down to play on NTSC. Both seem to end up doing the exact same thing in the long run don't they?
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Old May 5th, 2003, 03:10 PM   #12
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Boyd,

Sorry, didn't make myself clear, but I didn't want to open another can of worms.... Of course 16:9 FHA uses the full resolution of the tape and is the preffered format for distribution for UK broadcast.

The argument I was reffering to is as follows.

Question:

I have a camera with 4:3 CCDs but I want to make a widescreen movie..Do I shoot incamera 16:9 anamorphic or in camera 4:3 and crop it in post ?

Answer 1

16:9 FHA in camera: uses full res of the DV tape but only 3/4 of the CCD

Answer 2

4:3 uses full res of CCD but (when letterboxed) uses only 3/4 of DV tape. Additionally gives you a bit of framing leeway when racking.
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Old May 5th, 2003, 03:18 PM   #13
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Brad,

Didn't realize you were using the Canopus card. Is this a firewire card ?

I'm sure we can sort this out

simon
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Old May 5th, 2003, 03:23 PM   #14
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Yes its a realtime editing card/firewire card. When I view my 16:9 clips freshly captured, they aren't squashed at all, they look perfect.

It's only when I import them into After Effects that they start to look funny, because of the preset of 720x480, hence why in this shot

http://www.fusionarena.com/forumpost/wide.gif

my clip is wider than the widescreen AE composition. That's a 720 wide comp with the original captured 856 footage. (the rest of the footage on the left and right you can see if I move the clip in or out of the comp). But needless to say, this footage is definitly wider than 720. When I make my own comp at 856x480, they look perfect. I'm wondering if this is they way it's meant to be edited if output is to a widescreen television.
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Old May 5th, 2003, 03:25 PM   #15
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what i mean is ...is it firewire only ...or does it have an analog section too ?

si
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