[Pau Perez]

Thanks. I see there’s another issue with the pixel size (C4D exported video is 0.90:1 and AE’s NTSC DV is 0.91:1)… so I’ll interpret in AE following its NTSC DV standard for fps and pixel…

[Pau Perez]

So when I make a composition out of this video in AE, and it states it’s 30 fps, whenever I export it to 30 fps it won’t matter and will be actually 29.97? Or should I create the AE composition in NTSC DV 29.97 fps and drop the video into it after creating it?

Thanks!

[Pau Perez]

Thanks, with the formula deformer it kind of works in this case!

[Pau Perez]

Ok, that’s clear, but let’s get out of AE for one minute. Imagine any TV channel, like NBC. They have videos on the Internet with what they broadcasted on TV. What they broadcasted on TV is 4:3, and so is what they have on the web, when being a square pixel it should look like NTSC (3:2 I think). How do they manage? They cut? They stretch? The image doesn’t look stretched at all so I suppose they cut…

[Pau Perez]

Yes, I’m sure I’m not capturing 16:9 footage. In the after effects forum someone is telling me that PAL in square pixel looks in fact 720×576, that is 5:4. This is what he tells me:

—

It’s the same encoded aspect ratio, for native PAL devices the resolution is always 720×576.

Only in the cases where you want to see what those 720×576 encoded pixels will look like when displayed would you need to scale the image (yes scale it, stretch it) out to 768×576.

However, this is not the way I would recommend to work, instead I would recommend placing your non-square footage into a matching non-square comp and enabling pixel aspect ratio correction preview (it looks like a small screen with a double sided arrow running horizontally through it, it’s along the bottom of the comp preview pane). That way you are maintaining the same correct 720×576 encoded frame throughout the workflow.

To reiterate: unless you know what you’re doing, it’s best to always maintain the 720×576 resolution of the footage.

Whether the image is being displayed on a square pixel or non-square pixel device will determine whether those 720×576 pixels will appear to be 5:4 (square pixel device) or 4:3 (PAL device). We do not use different aspect ratios whether working on a square or non-square device, we just have to account for the different ways in which the same pixels are treated.

[Pau Perez]

Thanks for your long explanation. But I have a general doubt: Imagine any TV channel, like NBC. They have videos on the Internet with what they broadcasted on TV. What they broadcasted on TV is 4:3, and so is what they have on the web, when being a square pixel it should look like NTSC (3:2 I think). How do they manage? They cut? They stretch? The image doesn’t look stretched at all so I suppose they cut…

[Pau Perez]

No, my captured video is not square pixel. But I have to turn it square pixel in order to see it correctly for the computer, right? I want its natural proportions.

So, the point is, it is impossible to have square pixel PAL videos in 4:3 without squeezing or cutting. The natural look of the PAL video in a computer is 5:4, right? It’s just that I had understood that PAL on a square pixel device would be 768×576, but not by squeezing the image. I suppose that I’ll have to cut a part of it on top or bottom to fit the 4:3.

I just don’t understand why we have a different aspect ratio for non square pixel devices and for pixel devices. Imagine that you want to broadcast something and later have it on the Internet too. Broadcasted it will be 4:3, but on the Internet it will be 5:4 unless you deform or cut the image.

[Pau Perez]

But as a result it squeezes the image… So I assume it is impossible to have square pixel PAL videos in 4:3 without squeezing or cutting.

Thanks for your time anyway

[Pau Perez]

Yep, I’m capturing DV and I use Firewire. I use the standard 48hz DV for Pal available in Premiere (image size 720×576 (1,067); 25f/s; milions of colours…)

[Pau Perez]

Well, the point is I can’t transcode it to 640×480 without distorting it. When I write 640, it automatically writes 512. To change that I have to uncheck the “keep proportions”.

So, I capture the video with Premiere for example, but I tried also with the window movie maker to see what would happen… it happens the same.

I get a squeezed video that looks 768×576 when seeing it in the media player or quicktime for example. When I transform it to square pixel (converting it to a .flv file, or interpreting the footage in After Effects) I get a normal looking image, no longer squeezed, but that in fact is 720×576.

If you want I can e-mail you 3 seconds of a captured video for you to see if that’s normal or not.

My e-mail is paubcn@gmail.com