• Adobe After Effects

  rotoscoping interlaced footage

  Posted by Chicken Kebab on April 4, 2007 at 4:57 pm

  Hi everyone,

  I know there’s allot of info on this subject but i can’t help the feeling that I’m falling through the cracks a little bit on this one, so your advice or reassurance will be very much appreciated.

  I need to tightly rotoscope a large piece of some interlaced footage and then export it interlaced again for broadcast. Obviously all without losing quality. I’ve imported the footage (PAL, targa sequence by the way) and have set the import to 25fps, have separated fields (UFF) checked preserve edges(don’t know why), left remove pulldown off, and have dropped the footage in a comp set to 50fps so i can see both fields seperatly. So now i’m set to rotoscope correct??? The problem is as the frame changes to upper and lower there is a small shift up and down 1 pixel to accommodate the different fields, it’s very noticeable on locked of shots, and it’s definitely not because i have chosen the wrong field first. This is making the rotoscoping very difficult as i am having to work on literally every single frame as it shifts up and down. Do i need to bite the bullet here, or is there something I’m missing? If i deinterlace the footage and work from that, won’t i be loosing allot of the quality?

  Hours of my life are in your hands.
  Regards

  James

  Chicken Kebab replied 19 years, 1 month ago 2 Members · 2 Replies
• 2 Replies

• 

  Kevin Camp

  April 4, 2007 at 7:51 pm

  i think your workflow is good (although i don’t think you need preserve edges on if you are going to render back to interlaced)… i think it maybe your footage…

  does your shot contain sharp or contrasty detail around horizontal edges or patterns? detail like that would create issues with interlacing, and create a vertical shift like effect when you separted fields this way.

  if your 50fps comp workflow is too difficult to work in, you cound try the same workflow but with a 25fps comp, and render back to interlaced (your footage is actually still interlaced, the separate fields option just allows ae to apply effects as if it were progressive, but you can still render back out with fields on).

  Kevin Camp
  Designer – KCPQ, KMYQ & KRCW
• 

  Chicken Kebab

  April 4, 2007 at 8:07 pm

  Hey Kevin , it’s always good to know you on the right track. Nothing worse than spending a week on something and then learning you could have done it in 10 mins and 100 times better with the correct process.

  There is a lot of shelving in the locked of shots which i think could be causing the patterning you refer to. My test renders look fine so i guess it’s just a matter of pushing ahead.

  thanks for the post.

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