Pan/Crop Video limitations

TomG wrote on 12/12/2003, 5:08 PM

Perhaps this is a dumb question and please, don't hit the "ignore this user button, but ......

When Pan/Cropping on a DV Video (.avi), I would like to Pan/Crop on a speaker and use key frames to follow him as he walks around giving a sermon (i.e. the source media is at a greater distance than I would like to edit). I'm rendering to MPEG2 for DVD output.

I've noticed that, of course, the closer I Pan, the more distortion I get in the picture. But this distortion is not constant even though the Pan and source remain constant.

Is there any rule of thumb one should follow when doing a pan on a video or should this be just kept to a minimum (and let the camera do the panning)? I assume there is no filter or add-on which can remove such distortion....?

Thanks,
TomG

Comments

rebel44 wrote on 12/12/2003, 6:24 PM

First-do not worry about this "ignore this user". It was design for dummies.
I am ssuming that you notice this distortion after rendering. Try render in avi and see if you get those distortions. About the camera-better let the camera doing that and then edit unwanted clips. How many lines of res you camera have?

TomG wrote on 12/12/2003, 6:50 PM

Excuse my ignorance, but I don't know. It's an older Sony DCR-TRV103 NTSC camera. The level of distortion (fuzziness) in the picture is just the same in .avi as .mpg. I begin with a 720x480 and pan to a 391x266.

Thanks,
TomG

Jay Gladwell wrote on 12/13/2003, 8:20 AM

"I begin with a 720x480 and pan to a 391x266."

Tom, in the for-what-it's-worth deparment, what you've actually done is "cropped" the image. Another way to put it would be that you zoomed in on the image.

The term "pan," which comes from the word "panorama," refers to a horizontal movement, as in moving the camera from left to right or right to left.

All these terms can be a bit daunting at first, but it's not so bad once you get into it. You might want to browse this site: http://www.filmsite.org/filmterms1.html. Some items are very useful and others are interesting at best.

Hope this helps. Have a Merry Christmas!

J--

TomG wrote on 12/13/2003, 8:57 AM

Thanks, Jay... Terminology is important and I will strive to improve.

But do you have any insights as to the limits one can "zoom" into a DV? I guess as soon as you zoom at all, the distortion will start?

Merry Christmas,

TomG

Catwell wrote on 12/13/2003, 9:04 PM

When you zoom in you are essentially throwing away part of your image. Based on your description you have eliminated three forths of the information in the original frame. Vegas is very good at interpolating new data to replace what has been lost, but it cannot create detail that wasn't there. The more you zoom in, the worse the image will be. Try to keep your zoom to at least 1/2 of the original frame. Note that 360 x 240 is 1/4 of 720 x 480.

Liam_Vegas wrote on 12/13/2003, 10:00 PM

Another approach to minimize the pixellation ocurring is to find a way to keep your resulting image smaller than full screen. perhaps have some appropriate graphic or background and place this cropped video on one portion of the resulting frame.