1080i to SD: De-interlace or not?

I am cutting HD material (1920x1080i - Apple Prores 422 HQ) that I am dropping into an SD sequence.
After exporting a QT from the SD timeline, I notice so interlacing issues.
I applied the FCP de-interlace filter, and it looks fine.
However, the spot will be broadcasted. Does this has anything to do with de-interlacing or not?

> I notice so interlacing issues.

What interlacing issues? lines or stuttery frames?



www.strypesinpost.com

lines on fast moving shots

That isn't an issue. That's interlacing (the format). However, play it out on a properly connected broadcast monitor/TV to check for stuttery frames/inverted fields.



www.strypesinpost.com

but you'll agree that it doesn't look good which to me, makes it an issue
Therefore I am trying to fix it by de-interlacing but according to the research Ive done, I might not have to de-interlace if it goes to broadcast

>but you'll agree that it doesn't look good which to me, makes it an issue

Interlacing has been around since the invention of television. It allows for higher temporal resolution (smoother movement) at half the bandwidth, as the image is sampled at twice the frame rate. The lines are imperceptible when viewed on a properly connected monitoring system. On traditional CRTs, each field is displayed separately (at 50 or 60 Hz).

The reason you're seeing the lines is probably because you are viewing it on a computer monitor which usually displays both fields at the same time (progressive). All consumer TVs are designed to correctly deal with interlacing. Basically, you only de-interlace on mediums that cannot deal with interlaced formats properly (web or theatrical projection). De-interlacing basically gets rid of one field, and images will end up a bit softer, but that's a worthy trade off if your display medium cannot handle interlacing properly.



www.strypesinpost.com

So I shouldn't worry about what I see. I just did because it never really happened before, when I work in HD.
Is it because I converted to SD?
Thanks for the detailed answer Strypes

>I just did because it never really happened before, when I work in HD.

You should be able to see it if you're working with an interlaced format (including HD). If you have a 1080i60 clip, play it on Quicktime player, and make sure "deinterlace" is not selected in movie properties. In the FCP canvas/viewer, switch to view at 100%, and it will display both fields. Fit to window will discard one field.

One more thing, I won't count on FCP to do the down conversion to SD. It doesn't do it that well. I'd usually use hardware or Compressor (if hardware is not available).



www.strypesinpost.com

But what happens if I stick to the De-interlaced version (SD)?
Would that become a problem when airing?

if it's intended for broadcast, then i can think of two points to bring up:

1. you should check it on a broadcast monitor,
not worry so much about what a quicktime looks like on your computer monitor.

2. check your delivery requirements.
some stations don't want shows to be de-interlaced.


nick

I'll look into that.
Thanks

If you do de-interlace keep in mind that this will change the look of the motion in your final project. 60i video presents 60 images per second to the viewer. If you de-interlace you now will be showing only 30 images per second. That is closer to the 24 images that film is normally shown as than it is to to 60 images of traditional TV.

what about deinterlacing only the sections that are causing an issue?

If I want to re-interlace just to be able to watch on a monitor, how do i remove the filter?
I applied it on the sequence created when I dropped the HD sequence into the SD sequence.
I was tempted to use Remove Attribute and check filter, but was afraid to remove all the filters applied in the HD sequence as well? (and re-rendering is an issue as far as time)

"what about deinterlacing only the sections that are causing an issue?"

but ARE they causing an issue on a broadcast monitor, or TV style monitor?

personally i find it a bit disturbing when shots change from interlaced to progressive


"how do i remove the filter?"

a couple of thoughts:
tunr on the "Clip keyframes"in the timeline.
thats a tiny button lower left of the timeline (with a green and blue line)
blue lines indicate a motion effect on the clip,
green indicates a filter.
that could help you find the clips with filters.

double click a clip into the viewer, switch to the filters tab.
stay in the viewer,
and use the up or down arrows on your keyboard to step though each shot.
eventually you will see the clips with the de-interlace filters.


nick

Unfortunately no "real" broadcast monitor. Just a monitor hooked up wit AJA card...

Will try your recommendation

that'll do for interlacing issues.
old "glass" CRT tvs are great for interlacing issues.


nick