HD > SD down convert question

[Steve Roberts]

If you don’t want to see those, you need to remove pulldown and separate fields in the HD footage before scaling.

[Kevin Camp]

[Matt Rogers] “once I changed it from none to Lower First they disappeared. However instead of seeing “flicker” frames that I’m used to seeing in film down converted to SD with pulldown, there are duplicate frames instead.

It’s the duplicate frames that are vexing me. Everything looks fine played back at 29.97, but I wanted to make sure I wasn’t missing something. “

i’m assuming that in addition to setting ae to separate fields, you also set ae to remove a pulldown, right?

if so, the duplicated frames are normal…. if you place 23.976 footage (which is what you have once the pulldown is removed) into a 29.97 comp, you will see a duplicate frame every 5th frame. this is due to the differences in frame rate. if you simply set your comp to 23.976 your duplicate frames should disappear.

once down-converted to sd, you can reintroduce the pulldown in the render settings… set ae to render fields, set field order and then pick a pulldown. now, when it renders, the footage will be 29.97 sd.

i am concerned that what dave suggests may be true…. that the footage was edited without removing the pulldown. you’ll notice this problem after trying to remove the pulldown… the first shot will look good, but then a later shot will show interlacing/pulldown. if that’s the case, it will be some work to down-convert this piece, and what dave outlines are probably your best options.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Kevin Camp]

[Matt Rogers] “once I changed it from none to Lower First they disappeared. However instead of seeing “flicker” frames that I’m used to seeing in film down converted to SD with pulldown, there are duplicate frames instead.

It’s the duplicate frames that are vexing me. Everything looks fine played back at 29.97, but I wanted to make sure I wasn’t missing something. “

i’m assuming that in addition to setting ae to separate fields, you also set ae to remove a pulldown, right?

if so, the duplicated frames are normal…. if you place 23.976 footage (which is what you have once the pulldown is removed) into a 29.97 comp, you will see a duplicate frame every 5th frame. this is due to the differences in frame rate. if you simply set your comp to 23.976 your duplicate frames should disappear.

once down-converted to sd, you can reintroduce the pulldown in the render settings… set ae to render fields, set field order and then pick a pulldown. now, when it renders, the footage will be 29.97 sd.

i am concerned that what dave suggests may be true…. that the footage was edited without removing the pulldown. you’ll notice this problem after trying to remove the pulldown… the first shot will look good, but then a later shot will show interlacing/pulldown. if that’s the case, it will be some work to down-convert this piece, and what dave outlines are probably your best options.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Kevin Camp]

[Matt Rogers] “once I changed it from none to Lower First they disappeared. However instead of seeing “flicker” frames that I’m used to seeing in film down converted to SD with pulldown, there are duplicate frames instead.

It’s the duplicate frames that are vexing me. Everything looks fine played back at 29.97, but I wanted to make sure I wasn’t missing something. “

i’m assuming that in addition to setting ae to separate fields, you also set ae to remove a pulldown, right?

if so, the duplicated frames are normal…. if you place 23.976 footage (which is what you have once the pulldown is removed) into a 29.97 comp, you will see a duplicate frame every 5th frame. this is due to the differences in frame rate. if you simply set your comp to 23.976 your duplicate frames should disappear.

once down-converted to sd, you can reintroduce the pulldown in the render settings… set ae to render fields, set field order and then pick a pulldown. now, when it renders, the footage will be 29.97 sd.

i am concerned that what dave suggests may be true…. that the footage was edited without removing the pulldown. you’ll notice this problem after trying to remove the pulldown… the first shot will look good, but then a later shot will show interlacing/pulldown. if that’s the case, it will be some work to down-convert this piece, and what dave outlines are probably your best options.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Kevin Camp]

sorry for the multiple posts.. i’ve been having network problems for the past 2 weeks, and when my post just hung, i assumed it was another network problem here. so i kept checking settings, resting routers pinging things and then reposting my post….

but it seems it was just my impatience…

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Kevin Camp]

he mentioned that his hd footage was originally shot at 24p on film…. so i assume the company that did the transfer added the pulldown to transfer the film to tape, which was then captured at 29.97 with pulldown intact.

what i’m not sure about is if the hd footage was edited, or if these are single shots…. which is, of course, where all the problems may lay… although, he did mention that separating fields made things look good, and he seemed to only be concerned with the duplicate frames in a 29.97 comp…

there can be so many places in the 24p workflow that things can get messed up it’s hard to give the best advice without seeing all the footage.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Matthew Rogers]

Sorry for the delayed response.
I actually did respond, but my browser apparently decided better. Thanks for all your time on this. I did edit in 29.97. I was trying to create a generic clip to place a disclaimer on. We didn’t have anything to go on but the transfer tape which was in HD. I brought the SD master and the HD sections into Final Cut. I eye-matched the scenes and brought the pieces (SD and HD) into After Effects via Automatic Duck.
I used the SD master as reference and then scaled and repositioned as best I could.

By the sounds of it it looks like I should have removed the pull down, did my repo and then adding pulldown back in the render. Does that sound right?

Thanks again.

-Matt

Matthew Rogers
engine room
Boston, Ma
http://www.engineroomedit.com

[Matthew Rogers]

No it really was, I swear. It’s always the easiest of things that can go wrong.

We had about 13 different scenes to revise. Each with a different disclaimer. Unfortunately there was no generic master or EDL. So we had to create our own. There was a unique repo on each scene, I had a good time making sure everything matched. The disclaimer was the easy part. I actually didn’t notice the issue. The dub house was sending the commercial via DG (?) and it I believe the compression they used exaggerated the incorrect field order.

Either way it was a lesson learned the hard way. Thanks for everyone’s help on this. It’s helped me understand the innards of After Effects a little better.

-Matt

Matthew Rogers
engine room
Boston, Ma
http://www.engineroomedit.com