Fields question

[Kevin Camp]

“When your footage is for broadcast you should shouldn’t deinterlace the interlaced footage because it is supposed to be interlaced again after you render it out.”

it depends a bit on what you’re doing. if you are only color correcting or something that is not adding motion or modifying the vertical position, scale or rotation of the original video, then you are ok to not de-interlace, but you will then render it as progressive (since you didn’t de-interlace, you don’t want to re-interlace).

if you want to modify the vertical position, scale or rotation of interlaced video footage then you need to set ae to separate fields or you’ll have a real mess on your hands. you could then render back to fields if you wanted (rendering back to fields will look smoother).

i would also recommend separating fields if you want to add motion graphics to interlaced footage. this way when you render, you can render back to fields and your motion graphics will be interlaced too, so it will look as smooth as the video footage. even if you decided to render progressive, if you separated fields, then both the footage and the motion graphics will be progressive.

as for what to do with mixed interlaced and progressive footage… if you do have mixed footage, you should not separate fields (or de-interlace in any other way). this will degrade the quality of the progressive frames. this of course means that you won’t be able to modify the vertical position, scale or rotation of the footage and that your graphics will be rendered progressive over the interlaced video, but most people won’t notice much of a difference.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Elin Grome]

Thanks guys, that pretty much covers it

It’s all the those pesky details :p

[Kevin Camp]

since it sounds like he didn’t capture the footage, it’s hard to guarantee that the progressive footage came straight from tape (which would be interlaced).

if it was de-interlaced in something like ae and rendered at 29.97 progressive, then it won’t have fields, and separating fields would result in poor image quality of that footage (similar to field doubling).

we occasionally have that happen here do to our workflow, which normally involves rendering from ae as 29.97 progressive to avoid filed issues when renders are imported into our edit systems — the issues occur depending on how the avid’s are set to import. if they are using a local media drive then it gets ingested as d1 (486 lines) if it gets ingested to our unity drive then it becomes dv (480 lines) and avid will scale the render to fit… so if there is a mismatch between the render and the ingest the fields get all mushed up. 29.97 progressive just made it more of a brainless operation.

they are looking into upgrading to new fcp stations here within the next 6 months and i hope we can get a smarter workflow… of course then it will all be hd so there will be lots of other changes.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW