• Broadcasting

  Question re: interlacing

  Posted by Jeff Strachan on October 28, 2010 at 4:06 pm

  I am one of those old codgers that sometimes get put down on these forums. But I’m a nice guy!

  I was recently asked a question about interlacing that I simply don’t know the answer to.
  In analogue each field is a partial image separated in time by 1/60th(approx) of a second.
  In progressive digital each frame is a complete image of a single instant in time and displayed 1/30th of a second apart.
  Now interlaced digital; are the two fields partial images of two different instants in time that are separated by 1/60th of a second, or are they partial images of the same instant in time but displayed separated by 1/60 sec?

  Jeff Strachan replied 15 years, 6 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Gary Hazen

  October 28, 2010 at 6:29 pm

  That’s a bit confusing Dave. Interlaced and PsF are not the same thing.

  [Jeff Strachan] “…two fields partial images of two different instants in time that are separated by 1/60th of a second…”

  This is interlaced.

  [Jeff Strachan] “…partial images of the same instant in time but displayed separated by 1/60 sec”

  This is PsF.

  You could argue that PsF is interlaced, but you wouldn’t win that argument with an engineer.
• 

  Jeff Strachan

  October 28, 2010 at 8:07 pm

  “In between frame rates”
  Ugh! glad I am not the one writing NLE programs that have to work with this %$#%$

  yes, I had expected an array of possible frame/field arrangments but not something quite that messy.

  So the answer to my question is, “both, and more”

  Jeff Strachan
  CJBN TV
  Kenora, Ontario

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