Upscaling and cropping

Say I have a clip that has something on the borders that I don't want in a scene. Now if I wanted to crop it out, or expand the scene to 110% stretch, I lose pixels. How do I know how much I lost, and at what point would I have to change the clip from 1920x1080 to 1280x720. Shooting at 60i, don't think that makes a difference. Thanks guys.

Hmmm... its seems I lost my original reply. So I'll try again.

There's no hard-and-fast rule about when blowing up a shot becomes unacceptable. It depends a great deal on the content of the clip. For example, critical fine detail like peoples faces in the middle distance, or the text on signs, etc, would probably not stand much blowing up before the shot became unacceptable. On the other hand, a timelapse of soft clouds in a blue sky would probably be able to stand a great deal more zooming in before it became unusable. I recommend a high-quality pixel-for-pixel LCD monitor or a pro-grade CRT to make that call.

But remember that 'acceptability' varies by context: if the finished product is ending up on the web, the clip can handle a great deal - faces in the middle distance and text on signs wont be visible at a highly compressed 320x240 anyway. But if its going to be on the air or in a movie theater, the standards are much higher.

As far as how much you lose, it depends on whether %110 stretch means expanding the horizontal and vertical axes each by %10 or expanding the total area by %10. In the latter case, you lose %10, or 207360 pixels in a 1080 frame.

In the former case you lose %21. Here's how I reckoned that:
(1920x1080) / ( (1920x1.1) x (1080x.10) ) = 0.21.

That's likely to be noticeable, but as I said, depending on the clip, it may still be okay.

Upsizing an interlaced clip should be generally off limits because you'd mess up the field information.

"Upsizing an interlaced clip should be generally off limits because you'd mess up the field information."
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Sometimes it may be needed to upsize due to motion stabilization. After using a program such as After Effects CS3 to stabilize slight motions such as wind jitter or such you will need to upsize slightly to avoid having a clip with incorrect proportions or black edges on one of the sides. In this case progressive or interlaced really should not matter.
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Klipper, whatcha think, if ya have to expand the edges of a clip a small amount to move something that detracts out of view, or to compensate for removing motion, will that mess up an interlaced or progressive field info. I don't believe it will.
Don

As a general rule for stock, never upres your footage. Frame it right in the first place. If you absolutely need to crop something out, you can consider generating a lower resolution clip in post. If you're shooting 1080i, for instance, you can generate a 1280x720 version -- but make sure that the footage is deinterlaced before getting downsized.

It's always best to submit footage at native resolution and frame rate, with no scaling.

It is possible to 'fix' upressed footage, but its a pain in the butt
you have to do a whole lot more than sharpening the edges. You have to have like 10 layers and you have to add a ton of effects.

At that point its more CG than real footage. I once took public domain 640 x 480 footage and made it 'HD'... It looked pretty good but it was a little weird. (its not on p5 BTW)

Tom, you say 'but make sure that the footage is deinterlaced before getting downsized.'.
Why would I want to deinterlace interlaced footage. Can't I just 'crop' to 1280x720... and how do I do that with CS, anyone know? If I change my footage to deinterlaced, isn't that a bad thing? Since original was interlaced..

Do I then use a different codec instead of the mjpg b?
Thanks guys for your helps!

I do plan on doing some image stabilization stuff too, so I will need to familiarize myself with it.

BTW, there are some nice AE/Premiere plugins that do a DARN good job of upsizing video and keeping decent quality. It's mostly designed for moving SD footage to HD. You might check that out.

I guess I am still confused on the interlaced portion. If I deinterlace it, it then becomes progressive footage...which then needs to use a different codec?

720p is a progressive format, so if you are generating a 1280x720 version from 1080i footage, you will want to deinterlace before downsizing.

BUT, as I said, you really should not be making any changes to resolution or frame rate at all, especially if you're not absolutely sure about what you are doing.

Codec is not a big deal, but yes - if you are going to generate a 720p version, you should output in PhotoJPEG. 1080i should be motionjpeg.