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Interlacing Confusion – Argh
I’ve cut together some good footage of a big ferrari meeting I went to a couple of months ago [shot on sony hvr z1e], captured the footage [was shot in SD], then I rendered it out so it could go into AE 6.5pro.
The footage is widescreen D1\PAL – interlaced
Some of my shots were kinda jerky, so I thought I’d use my steadymove pro plug in to sort that out, no problem, bit of colour correcting ect ect rendered it back out:
I made sure that the output included the interlace, and set it back to microsoft DV.
Upon viewing with windows media player, I saw that the footage was REALLY interlaced, VERY noticable, however the original footage you could barely see it. So I checked media player and made sure it now rendered the footage in “high quality” mode under the advanced tab. Played the footage back and now it looks fine.
However I played that footage on “power dvd” and it looked terrible again.Which one is playing the truth ?
Was I doing everything correct ?
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10 Replies
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I am far from being an expert on any of this but I am sure that if I am wrong one of them will solve your problems for you, so
have you tried watching this rendered footage on a tv screen or refecence monitor?
hope it helps, sorry if its not the case
renato
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Check that the footage is interpreted correctly in your after effects project, it needs to be separating the fields (upper or lower first for Pal DV? I can’t remember) then you need to do a field render with the same field order.
That should work, I wouldn’t worry too much about which application is showing you the right thing as some of them deinterlace and some don’t.
Hope this helps,
Glenn Stewart
1K Studios -
Yeah its lower first for PAL.
Right its annoying not being able to tell what is playing it properly.
I’ll try and play it on a TV [the only way I can do that is by making a DVD at the moment]. -
I also just tried this out:
Rendered from Prem – with interlacing, then rendered from AE without interlacing set in the render dia, then imported back to prem, rendered out with interlacing this time… looks fine on the players that were displaying bad interlacing from AE originally.
When I say BAD interlacing I mean its hideous, when the original footage you couldn’t even see it.
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Here’s what I know. Or at least what I’ve found. I hope it’s relevant:
1. In AE, if you import an interlaced movie and plan on scaling it, moving it vertically, blurring it, rotating it, or otherwise distorting it, you should separate its fields on import. You will then be looking at only one field’s worth of info (basically) while working. If you then tell AE to render fields, the field info will be returned to the clip and rendered as scanlines relative to the resulting frame (not the old frame if you, say rotated the video), and the animated motion in AE will be field-rendered.
2. If you don’t want to do all that scaling, moving, distorting (etc.) stuff to the clip, and you just want to leave it in the center of the frame, don’t separate fields on import. Separating in that case will degrade the image.
3. If you render out of AE without fields, that field info is gone. Kaput. You have 25 (whatever) full frames per second. No field info.
4. If you scale a non-separated fielded clip in the Y (or X&Y) direction, you’ll get thick and thin field lines, kind of like a simple moire pattern. If somebody ever gives you footage that looks like that, you can’t fix it. You need the original.Steve
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Ah yes thats sounding more like it.
Well the Steadymove pro plug in effectivly zoom’s into the image a little bit, once its steadied the footage [to remove the resulting black boarder].So import it with fields, but export it with non.
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So if the Steadimove plug is within AE, then the interlaced (with fields) footage should have had its fields separated automatically when imported into AE. If not separated automatically, you should interpret the footage again, separating fields this time.
Then you steadymove, then render out of AE with fields if you want fields in your final output.
If, however, you export out of Premiere with no fields (as “progressive” footage or “frames”), then you import that progressive footage into AE, you’ve lost the field information. Gone. If you then SteadiMove and render with fields, the action in the footage will no longer be interlaced because it wasn’t there when you imported the footage. (I can’t say if there would be interlacing artifacts due to the steadymove or not.) It should look fine, just not as smooth (or video-like) as interlaced footage.
Remember: using fields or not is an aesthetic decision if you don’t need to match interlaced footage. However, if you choose to work with fields, you should know how to avoid messing them up. 🙂
Get Chris & Trish Meyer’s AE books. They’re a necessary part of every AE user’s library.
Steve -
Many thanks for the help, I guess I was only confused because of the playback being odd.
I prefer to work without interlacing anyway, but magic bullet takes a heck of a long time to deinterlace 25mins of footage 🙁 -
Ok last thing I promise: [sort of :)]
Why then does the original footage look fine when rendered out of premiere pro before going into after effects? [just using media player classic to view it]
When the footage is interpreted with interlacing, and rendered without interlacing it looks as far as I can tell fine [on my monitor] once again with media player classic.
Only once I’ve set after effects to render with interlacing that it becomes visible [including the interpreted interlace]. Which you can also see in premiere.It just seems to me that I shouldn’t be interlacing the footage for the render out of after effects, but once it’s gone back into premiere pro I need to set it back to interlacing [and once again it looks fine].
I want the footage to look clean on pc monitors as well as tv screens.
[I remembered I once rendered something out of premiere and I forgot to include interlacing, the footage looked slightly blurry.]
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Ok, its definatly something to do with steadymove pro, because I just rendered out the footage without any effects and interlaced it both ends, and one with just the interlaced import…both look fine, hard to tell if the 2nd one is slightly blurry or not because its a fast moving shot [doh].
Im going to try another steading plug in.
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