Resolution Catch-22

John Ealer · July 27, 2004

An upcoming project will be finishing to video for initial festival release, but hopes to do a film-out shortly thereafter (i.e. when a distributor picks up the project on the back end.)

The catch-22 is whether to use Interlace or Progressive resolution mode. Conventionally speaking, interlace would be likely be a safer choice, as it would probably have somewhat better results for the video finish, at the expense of being slightly less crisp in the final film output, if and when that happens.

Any thoughts or experiences in this regard are much appreciated.

Regards,

John

David Mullen ASC · July 27, 2004

Why would you want to shoot in interlaced-scan mode on that camera EVER except for non-fictional material (documentary, sports, news)???

The camera always records interlaced-scan, so stores progressive scan capture as two fields, plus a pulldown if 24P is used and it is a 60i camera (not an issue if you are shooting 25P onto a 50i camera). You are not losing sharpness by shooting in progressive scan and you will definitely be gaining vertical resolution for moving shots whenever you show the image on a progressive-scan monitor or transfer it to film. But you do not lose resolution by viewing or editing the progressive scan material as interlaced-scan. You do have less "temporal resolution" (fewer motion samples per second) but that's the look of 24 fps film -- very high sampling rates make the image very fluid and "hyper-real", i.e. more like traditional video and less like 24 fps film.

There's nothing "unsafe" about using progressive-scan mode on that camera; it's the same as transferring 24 fps film material to NTSC. Would it be "unsafe" if you had shot your project in film? No. If anything, it's less "safe" to use interlaced scan mode because that would definitely create that standard video look which might turn off a potential distributor.

Phil Rhodes · July 27, 2004

Hi,

It's not particularly "better" results for the video finish. It may be more appropriate if it's a sports documentary, but that's a pretty specific situation. If it's drama it's more likely to be appropriate to do it progressive irrespective of the final format.

Phil

David Mullen ASC · July 27, 2004

Another thing, use 24P, not 30P, for anything to be transferred to film or converted to PAL someday.

Jan Crittenden · July 28, 2004

I think the question does not reference whether it is interlace or progressive capture, but rather there is a setting in the camera for V. Res and its choices are interlace or progressive. If you are shooting in 24P/PA or 30P the camera can record 480 lines of vertcal resolution. This is great for film-out work. This is the Progressive choice.

The problem is that when you shoot for video release aka an interlaced display, the TVs can only show 360 lines of v. res. Any more can turn into excessive aliasing, or what looks like odd noise. The Interlace function of the v. res choice rolls off the vertical resolution to about 360 lines. This is the same set of choices as in the DVX100/A v.res called Thick or Thin.

So here is his question, does he deal with the excessive aliasing for his video release?

My answer is that if he is going to up-res to HD for his vestival release, the I would shoot with the Progressive. If not, then no, and that way when and if it does get picked up, you can in the up-res add some detail in the HD suite.

Reactions?

Best regards,

Jan

John Ealer · July 28, 2004

I'm sorry if the question lacked clarity.

Jan got exactly what I was after. It's certainly not a choice between 24p or 60i; we'll shoot 24pa and edit in a 24p timeline. It's a question of the V.Res mode.

My instinct was to go interlace as the festival release is likely to be standard def, and deal with the options to add some detail enhancement back in later for a high-def finish and / or film out.

My experience has been that you have better luck adding a bit of detail enhancement rather than trying to remove aliasing.

Any additional thoughts or comments appreciated. Thanks for the feedback.

John

Phil Rhodes · July 28, 2004

Hi,

I'd certainly shoot with this in whatever the "off" mode is. If that means it's going to flicker in interlace, you can always blend fields later - this is likely all the setting does anyway, and then you'll have best resolution for the filmout.

Phil

Jan Crittenden · July 29, 2004

Phil,

It will not flickr, it will just have too much res for video, so the resolution is that if you do shoot it this way you need to filter in post to lose some of the vertical res or gain it back later in Hd up res. That's all.

Best Jan

John Ealer · July 29, 2004

Thanks for the feedback.

Final decision based on this advice and the input of some post-production folks is to shoot in the PROG v.Res mode and just add the filter for any aliasing problems that might occur in SD.

Thanks,

J