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cropping large files - Region of Interest unreliable

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James St Clair
cropping large files - Region of Interest unreliable
on Apr 7, 2011 at 9:26:23 am

Hi AE,
I've looked @ for this one, it seems obvious, but haven't found any direct info about it in Creatve Cow.

The issue is using large files (bigger than 720x480), I'm using currently files betw. 3,000-5,000 px square. These need to be rendered finally to ntsc 720x480. There is on the output module a box I am checking that says "Crop" and I then check a sub box called "Use Region of Interest".

This method only works sort of. The two main downsides are 1. Using the ROI is sometimes significantly inaccurate. What I see in the ROI is often not what I get in the final crop.
But mainly the problem is, the ROI renders the file cropped, but there does not seem to be any way of specifying final file size and aspect ratio. I've been importing large files into Final Cut, then exporting them as ntsc DV, and reimporting them. Surtely there's a way to get the file size I need directly out of AE?

QUESTIONS: Is there a way to easily specify the end crop AND file size? AND I've got in Comp Settings the aspect ratio set to square pixel. Is this correct for ntsc 720x480? I'm always having to adjust the aspect ratio in Final Cut after importing the clips. Which is do able for 20 sec or less clips, but after that it becomes a major time consuming job...

thanks
James


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Walter Soyka
Re: cropping large files - Region of Interest unreliable
on Apr 7, 2011 at 2:44:33 pm

Why use the ROI for cropping?

If you need a 720x480 crop, I'd drop the photos into a 720x480 composition and re-scale and re-position as necessary.

720x480 NTSC uses non-square pixels (PAR 0.91).

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Everett Keithcart
Re: cropping large files - Region of Interest unreliable
on Apr 15, 2011 at 10:37:57 pm

Thanks guys, new AE user here, I've been searching all over for the answer to a similar "Crop" question.

MY GOAL: use a 720p section (@100% size) of a 1080p .MOV, for a nice "crop" with no degradation in image quality from the original, only reduced size.

Coming from a Photoshop background and not finding a "Crop" tool, it made sense to want to crop using ROI+Output checkbox or some funky workaround with Masks or something...

<> ~ Walter

So, what I'm hearing is, don't crop to get desired final output size, rather, make Comp file with the desired size and import into that. Is that right?

Thanks!


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Walter Soyka
Re: cropping large files - Region of Interest unreliable
on Apr 16, 2011 at 2:27:24 am

[Everett Keithcart] "MY GOAL: use a 720p section (@100% size) of a 1080p .MOV, for a nice "crop" with no degradation in image quality from the original, only reduced size... So, what I'm hearing is, don't crop to get desired final output size, rather, make Comp file with the desired size and import into that. Is that right?"

Yes. Bring your 1080p material into a 720p comp.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Dave LaRonde
Re: cropping large files - Region of Interest unreliable
on Apr 7, 2011 at 2:54:10 pm

[James St Clair] "...there does not seem to be any way of specifying final file size and aspect ratio. I've been importing large files into Final Cut, then exporting them as ntsc DV, and reimporting them"

Your workflow will result in degraded image quality. I recommend doing the work in AE, putting the big images into a comp using the NTSC DV comp preset, and RENDERING -- using the AE Render Queue and not the export function -- either in a lossless codec, or in your case, something like ProRes 422.

By using a comp preset, you don't have to guess about the size of the image: it's fixed. By using the Render Queue, you can specify default Render Settings and Output Module, so you simply add the comp to the Render Queue, no guesswork necessary: you've already done it. A further virtue of the Render Queue: you can set up multiple comps to be rendered; batch processing, y'know.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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James St Clair
Re: cropping large files - Region of Interest unreliable
on Apr 7, 2011 at 3:05:16 pm

@Dave, @Walter
thanks for the replies, I think I must be missing something basic. The reason the files are so large is because I have a 720x480 video clip sitting in a landscape which is about 15 times bigger than the clip. I pan and zoom into the clip from "far away" across a large landscape.

So if I have a comp preset that's 720x480 how am I going to get that video clip to be sitting in the huge landscape it needs so I can pan for a while and arrive finally at the video clip filling the screen?
thanks
James


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Dave LaRonde
Re: cropping large files - Region of Interest unreliable
on Apr 7, 2011 at 3:11:51 pm

If I understand what you're trying to do, how are you integrating the 720x480 clip into the larger background?

Is the 720x480 clip simply a 4x3 rectangle sitting in the midst of these big images?
Have you masked or keyed around around the subject in the 720x480 clip?

Just what are you doing? Sorry, but I'm not following it.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Walter Soyka
Re: cropping large files - Region of Interest unreliable
on Apr 7, 2011 at 3:22:21 pm

[James St Clair] "The reason the files are so large is because I have a 720x480 video clip sitting in a landscape which is about 15 times bigger than the clip. I pan and zoom into the clip from "far away" across a large landscape. So if I have a comp preset that's 720x480 how am I going to get that video clip to be sitting in the huge landscape it needs so I can pan for a while and arrive finally at the video clip filling the screen?"

If I'm understand what you're trying to do, then I think you're misunderstanding how to use compositions. (If not, please post a screenshot or two of your AE workspace with one of your comps open -- seeing what you're working with might help us help you.)

Your comp should match your best deliverable -- not necessarily your original source files. If you're delivering to standard definition NTSC, you can use a standard definition NTSC comp. If you're delivering to HD and SD, work in an HD comp.

There is no need to use a huge comp that was the size of the original image, only to crop it down later. You can still do your big 3D camera moves in a standard video-sized comp. AE will handle all the scaling and positioning correctly.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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James St Clair
Re: cropping large files - Region of Interest unreliable
on Apr 8, 2011 at 8:38:53 am

"Your comp should match your best deliverable -- not necessarily your original source files. If you're delivering to standard definition NTSC, you can use a standard definition NTSC comp. If you're delivering to HD and SD, work in an HD comp."

No need for screenshots. That's hilarious, I knew I was missing something. Someone in the beginning showed me how to import the PSD files into After Effects directly as a composition, so that's how I was doing it. Import -> File, option "As Composition." So the composition size was the size of the PSD file, a couple were over 6,000 px wide. Every time I moved the timeline I had to wait ten seconds for the preview to update, and I'm using a Macbk Pro 2.53 Ghz machine w plenty of RAM. Cropping accurately was a problem, and I had to wait 2 hours for a 20 second clip to render. I was thinking, my god I have to get a new computer now, this one is too slow. Lol.

I tried doing what you suggested, and that solved everything. I didn't realize the 720x480 frame in the NTSC preset was also the preview window and I could simply import the PSD files as a group and dump them into the composition. As you can see, I just started with AE last month. The 23 sec. clip I just did that way rendered in 4 minutes. Thanks for answering all my questions.

thanks
James


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James St Clair
Re: cropping large files - Region of Interest unreliable
on Apr 11, 2011 at 11:35:44 am

By the way,
I've been using forums for open source and retail software since 2004, but Creative Cow's forum is the highest quality forum I've ever seen. Amazing resources from some impressively qualified people. The project I've been working on for 6 wks is finished thanks to the help here on After Effects, it's a music video of a cover of All Along the Watchtower. Does Creative Cow sponsor any events where that could be shown?
James


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