• Blackmagic Design

  Deinterlacing 1080i with hardware like the UpDownCross?

  Posted by Dan Swiney on July 26, 2012 at 12:54 am

  My knowledge/understanding is a little weak in this area, I am hoping someone can correct any misconceptions I may have.

  The problem:
  I will have an HD-SDI 1080i (29.97fps) feed handed off to me.
  I bring the signal in using a BM Ultrastudio 3D, thunderbolt.
  I will be using Wirecast to encode and stream that signal at 1280×720.
  There is de-interlacing within Wirecast as a software solution, but it boosts CPU use and doesn’t do the best job.

  Normally I use a 1080p or 720p workflow to eliminate this issue, but in this case I have to take what I am given.

  The available gear:
  BMUpDownCross, it can do a conversion, but is it deinterlacing?
  Aja KiPro, which can convert 1080i to 720p but it is not de-interlacing?

  My basic confusion seems to be, is a conversion from 1080i to 720p by definition also doing the deinterlace?

  Juan Salvo replied 14 years, 1 month ago 2 Members · 1 Reply
• 1 Reply

• 

  Juan Salvo

  July 26, 2012 at 6:06 am

  [Dan Swiney] “My basic confusion seems to be, is a conversion from 1080i to 720p by definition also doing the deinterlace?”
  Yes. By definition a 720P (as in Progressive) signal cannot be interlaced.

  That said what usually happens in cross conversion is each 1/59.94th field is scaled to it’s own 1/59.94th frame in the 720P image. Combine both fields by quickly showing one frame after the other and you get a fluid looking image, like a 60i image. However each individual frame would have to be a progressive image. As that is what the format requires.

  So to answer your question, any device properly converting to 720P is deinterlacing.

  Colorist | Online Editor | Post Super | VFX Artist | BD Author

  https://JuanSalvo.com

Reply to this Discussion! Login or Sign Up