ADOBE AFTER EFFECTS: Forum Expressions Tutorials Creative Cloud

HD field problem

COW Forums : Adobe After Effects

<< PREVIOUS   •   FAQ   •   VIEW ALL   •   PRINT   •   NEXT >>
Bob Root
HD field problem
on Nov 2, 2010 at 10:45:02 pm

Hi all. I hope someone can help me make sense of this.

I have a very basic HD project that is basically keyframed text over a BG. Nothing to dramatic.... just a :02 move vertically and scale down.

My composition settings are HDTV 1080 29.97.

My render setting in the render cue is set to Upper Field First and I am rendering uncompressed at 1920x1080.

After the render, I am taking the movie file into my Smoke for QC on an HD monitor. All settings on the Smoke are correct and confirmed.

For some reason, the field dominance in my AE movie file is reversed.

I went back into my AE comp and changed the render setting to Lower Field First and this fixed the problem.

This really makes no sense to me, as I know Upper Fields should be the correct way to render out my comp.

I must be missing something... but I've been in and out of all of my settings and can't find a thing.

Unfortunately I'm not on my system right now, so I can't upload any screenshots or explore the problem further until tomorrow morning.

Thanks for any suggestions you may have.

Regards,

Bob


Return to posts index

Dave LaRonde
Re: HD field problem
on Nov 2, 2010 at 11:27:54 pm

It doesn't sound as if you interpreted the footage as upper field first. If you both interpret and render 1080 footage as upper field first, it's tough to go wrong... even if it was shot progressive scan. Unless, of course this was shot on a RED or something...

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

Bob Root
Re: HD field problem
on Nov 2, 2010 at 11:38:39 pm

Hi Dave,

Thanks for the quick response.

Everything is interpreted as upper field first.

The odd thing is that the keyframed text layer shows all the signs of reverse field dominance when viewed on the HD monitor.

As I said, it does correct itself when rendered lower fields

Thought I was an intermediate user but this one has really thrown me for a loop.

Forgot to mention that this is CS3 (maybe a bug?).

Bob



Return to posts index


Dave LaRonde
Re: HD field problem
on Nov 2, 2010 at 11:41:35 pm

[Bob Root] "Forgot to mention that this is CS3 (maybe a bug?)."

Yup. Sure could be, especially if you're working with HDV footage. Since you're on AE8, this still applies:

Dave's Stock Answer #1:

If the footage you imported into AE is any kind of the following -- footage in an HDV acquisition codec, MPEG1, MPEG2, AVCHD, mp4, mts, m2t, H.261 or H.264 -- you need to convert it to a different codec.

These kinds of footage use temporal, or interframe compression. They have keyframes at regular intervals, containing complete frame information. However, the frames in between do NOT have complete information. Interframe codecs toss out duplicated information.

In order to maintain peak rendering efficiency, AE needs complete information for each and every frame. But because these kinds of footage contain only partial information, AE freaks out, resulting in a wide variety of problems.

I'm a Mac guy, so I like to convert to Quicktime movies in the Animation or PNG codecs; both are lossless. I'll use Apple's Compressor, Adobe Media Encoder or Quicktime Pro to do it.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

Bob Root
Re: HD field problem
on Nov 2, 2010 at 11:40:46 pm

Forgot to mention that this is all graphics... no camera.



Return to posts index

Dave LaRonde
Re: HD field problem
on Nov 2, 2010 at 11:48:30 pm

Is it all progressive-scan, then? Set the field order to NONE every place.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index


Bob Root
Re: HD field problem
on Nov 2, 2010 at 11:53:09 pm

The one .mov (animation codec) I have is upper fields and interpreted as such.

The client is looking for 1080i deliverable.

I'd like nothing more than to do the progressive workaround though (:



Return to posts index

Dave LaRonde
Re: HD field problem
on Nov 3, 2010 at 12:03:42 am

The footage could still be progressive, but recorded as Progressive Segmented Frame... or psf.

It works like when you render frames-only SD quicktime movies. You really do record two fields, but since they're from the a single frame rendered at a single point in time, it looks like a frame.

When you render fields, you render at two different points in time to make a single frame. That's why the motion of interlaced SD footage is smoother than progressive SD footage.

If you put the movie in question into a 59.94 comp, then step through frame by frame, do you see motion on each and every step, or every other step? If it's every other step, you can do your voodoo with NO fields, and it ought to work fine.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

Bob Root
Re: HD field problem
on Nov 3, 2010 at 1:23:07 am

Hey Dave,

Thanks so much for your help!

My (Smoke) system is actually set up with a TriSync of 59.94 for any and all HD projects. There's definitely something going on there.

Thinking back on earlier projects, I've had some interlacing issues bringing in HD movies from AE. A lot of the time we resolve by just going with progressive.

I'll give you a shout out when I figure this thing out... definitely a lot closer now.

It seems a bit of anomaly (or maybe just a brain-fart) on my end. I'll know better in the morning.

Thanks and regards,

Bob



Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]