Problem with ratios when importing video.Help please!

[shy-guy]

So... i´ve been reading the help files (yeah,i should´ve done that before writing the first post) and i understand a little bit better the problem, but i didn´t solve it. The reason why i wasn´t very familiar with this subject is because i dont have much experience with importing videos in AE, i generally do animations from scratch there or import 3d animations from 3ds Max, and they all look alright.

I read this from the help files:

"If you display nonsquare pixels on a square-pixel monitor without alteration, images and motion appear distorted; for example, circles distort into ovals. However, when displayed on a broadcast monitor, the images are correct.

To view nonsquare pixels on a square pixel monitor, choose View Options from the Composition panel options menu and then select Pixel Aspect Ratio Correction. Because it slows performance, this is recommended for viewing only. (I did this and yeah... the video looks about right in the program, but it doesn´t affect the rendered video as i assumed)

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When you import D1 NTSC or DV source footage into After Effects, the image looks slightly wider than it does on a D1 or DV system. (D1 PAL footage looks slightly narrower.) The opposite effect occurs when you import anamorphic footage using D1/DV NTSC Widescreen or D1/DV PAL Widescreen. Widescreen video formats have a frame aspect ratio of 16:9."

So,this info was really useful to understand the problem im having, but.. i still dont know how to solve it.

The videos im doing are just for training purposes; im doing some tutorials to learn VFX tricks, and i just want the videos to look properly (with the "correct" ratio) and not streched out or squashed,in these scenarios:

- Here in my computer for when i show the video to someone.
- When i upload it in youtube or whatever.
- If i decide to put one of the vids in my dvd reel.

From what i´ve read in the help files, the solution i could come up with (i assume that it might be incorrect),for the first two scenarios i described,its what i wrote in the first post,to change the Pixel Aspect Ratio of the composition to Square Pixels, and scale the video accordingly (choosing between having black bars at the sides or top/bottom of the video, or fill the whole composition but loosing part of the image).And for the third scenario,to leave everything as it is because it will look ok when i burn the dvd and see the video in my tv.

Am i remotely correct? Again... i would greatly appreciate any help.

[Mylenium]

Am i remotely correct?

Not at all. You simply drop your footage into a square pixel comp and that's it. For NTSC widescreen that would be 864x480 px. No scaling or additional fitting required. This way you also simply reverse it after you've done all your work by dropping your square pixel pre-comp into a proper anamorphic comp. And seriously, next time keep it brief. No need to quote the help files in full length...

Mylenium

[shy-guy]

Hey there Mylenium. Thanks a lot for your answer,and sorry for the long posts,i see that quoting the help files was redundant.

Your name pop up a few times in threads regarding aspect ratios and the like when i was searching for info here, so im aware that you really know what you´re talking about,and that these types of questions must seem a little moronic, but still you answer them. Thats really cool.

Okey,so i read what you told me,and i read some info about anamorphic formats and aspect ratios,and my brain is starting to hurt a little. Mainly because of the meaning of the word "anamorphic"... i´ve read a lot about it,in wikipedia and here,and i still haven´t had a grasp on it.

Anyways,i did what you say and yea,the video (the one shot with the 16:9 format) looks exactly the way it looks when played in Windows Media, it looks "correct",without black bars or loosing any part of the image. So, i render from this comp to solve the first and second scenarios i described earlier,right? (to see the video correctly in the computer and in youtube like websites).

And when you say that i can simply reverse it when i´ve done all my work and drop the square pixel precomp into a proper anamorphic comp, do you mean (and im afraid of sounding more stupid here) dropping the pre-comp into a comp with the "NTSC DV Widescreen" preset? So,when i render the video in this comp, although it will look squashed horizontally in my computer monitor, when i import this video into a dvd authoring program and burn it,it will look correctly in my standard and/or widescreen tv? (with the black bars at the top and bottom for a standard 4:3 tv and without them in a widescreen one... i suppose?)

One last question... if this is the procedure for the videos i shot in the 16:9 mode, how would i go about with the ones shot with the 4:3 aspect ratio? What resolution would i use in the square pixels pre-comp?

Sorry if im making a whole other bunch of misconceptions,im just trying to understand these concepts.Thanks in advance mate.

[Mylenium]

No no, don't worry. No need to feel noob-ish.

dropping the pre-comp into a comp with the "NTSC DV Widescreen" preset? So,when i render the video in this comp, although it will look squashed horizontally in my computer monitor, when i import this video into a dvd authoring program and burn it,it will look correctly in my standard and/or widescreen tv?

Yes, exactly. AE does the conversion based on its internal math. You could even do this differently with a mix & match approach, i.e. creating an anamorphic comp with the footage and another square pixel comp dropped into it that holds your text or whatever elements, which one preferably creates at square ratios to better be able to gauge their quality and things like spacing and kerning... Once you get over your initial fear and have tried it a few times, you will understand how it works intuitively. For 4:3 the proper NTSC square pixel equivalent shoudl be something like 720x504. Just choose the proper NTSCS D1 Square Pixels preset.

Mylenium

[shy-guy]

Hey again. Thanks a lot for your help mate,really. Im beginning to understand the whole deal with the aspect ratios and square pixels and such.

One last thing.When i drop the 4:3 video into a comp with the "NTSC D1 Square pixel" (that has a resolution of 720x540 like you pointed out), the video looks right,not streched out or squashed, but it has spaces up and down and on the sides. Making some test and changes, i find that the resolution that perfectly fits the video (in the square pixel comp) is 640x480. What does that mean? If i want to watch that video in the pc monitor properly,do i render it with the 720x540 resolution and the black bars? Or do i scale the video up to make it fill the screen in that res? Or do i change the res to 640x480 and render that?

This is the last question regarding this subject, promise :)

[danielHinton]

hey.

I feel like I may be a little late, but my views on aspect ratios in AE generally follow this format:

1. make sure I'm aware how the footage should look
2. make sure I know what the various video standards look like (fortunately, it's PAL 99% of the time here!)
3. I never work in square pixels unless I'm exporting to a web-only output
4. that means that I only ever change the aspect ratio of what I produce at export/render time
5. I start off in "anamorphic" mode (pre-stretch). in PAL terms this is 720x576. the comp settings I use are dv pal widescreen 1.42 PAR.
6. this means that - pre aspect ratio correction inside the comp viewer settings - I'm viewing horizontally squashed pictures
7. in the comp viewport i use the PAR correction option to make everything look as it should. this has worked flawlessly so far, with output direct to DVD and export to tape via an Avid.

I hope this helps - it took me a while to get my head around the whole video issue too. How are you with fields??!! ;) :banghead:

[danielHinton]

actually looking at your last post, the thing you need to remember is: always work in square pixels when outputting for systems without pixel aspect ratio correction. as a general rule this means that only DVD players and TVs will need non-square output...

again, hope that makes sense!

[shy-guy]

Hey daniel,thanks a lot for your answer,and its not late at all.

Yeah, what you say fits perfectly with what I have been learning about the aspect ratios deal. Little by little the whole mess its starting to make sense.

I think i have enough info and understanding now to not screw up the ratios of my vids in the different scenarios that have been discussed in this thread.

Thanks a lot for the help, Cg Talk rules :)

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