Letterboxing remove problem

Hello,

I am having a problem in the removal process because of the black bars/letterboxing in the video. I made cleanplates in Photoshop and cropped the bars out, but the problem with that was that it stretched the image when removed. I put the bars back in, but they travel with the tracking data and are present in the remove. Is there a way I can crop them out but not necessarily crop the image, so that the image doesn’t get warped? Thanks!

Alyssa

Martin,

Thanks for your response! I have been cropping the bars out in the clip tab, but I get the same result. It’s cropping the clip but not the cleanplate, and I tried cropping the cleanplate myself but that’s what caused the stretching. I am removing a large portion, if that helps at all. Do you have any ideas of what might be happening? Thank you!

Alyssa

Martin,

I am using cleanplates exclusively, because I am removing static overlay, so if I don’t use cleanplates exclusively it picks up things from the previous frames that should not be there.

Martin,

Thanks very much for looking into that for me! How would I go about recomping the render to the letterbox? Also I have one other question. Is it possible to use a cleanplate larger than the frame? Sort of like a panoramic cleanplate… The problem I am having is with a long pan shot I am using several cleanplates, and as it loses information from frames, it uses the next available cleanplate to replace with, resulting in a line where you can see the next cleanplate coming in(because of lighting changes and such). I tried importing one with 3 cleanplates overlapped and the dimensions were 2301 x 1238, but Mocha just squished it all together to fit to the original dimensions. Thank you for your help!

Alyssa

Martin,

Thank you very much for your help! It is working out well so far. I will email you if I have any other questions!

Alyssa

Hi Alyssa,

Do deal with letterboxing, just mask out the clip by:

  1. Go to the Clip tab
  2. Go to the Mask subtab
  3. Either crop by dragging the dotted lines in the viewer, or entering numbers into the fields

Anything masked here will be ignored in the other modules. This means you can avoid cropping plates and keep their letterbox.

Hi Alyssa,

Are you using clean plates exclusively or a combination of the standard remove and the clean plates?

Hi Alyssa,

It appears this one is a bug with the clean plates. It should respect the original masking, as it inherits from the base clip, but you are right, it does not.

At present the only work around I can think of is cropping out the letterboxing in both then recomping the render back to the letter box.

An alternative is to create the clean plate with an alpha crop on the letter boxing (i.e. delete the black borders but leave them as blank alpha), but I’d have to confirm this works.

We will investigate the bug!

Hi Alyssa,

To recomposite the shot it depends on what you are currently using for your comp software, but I would recommend something like After Effects to insert the rendered layer on top of your original footage then mask the original bars over the top.

The reason the clean plate would be squishing is that it inherits attributes from the original clip in order to maintain consistency.

If you are getting lighting changes in the remove, you are better off using linear illumination as this will try to accommodate for the light shift over time.

Removal in passes is not uncommon. You can either do it the way you suggested, or you can set a new input and output clip in the remove module.

If you like I can take a look at the footage as sometimes it is easier to solve these by seeing exactly what you are trying to do: martinb[at]imagineersystems.com