Scan lines?!?!?!

[John Harris]

Sorry for the newbie question, and i'm sure someone out there already knows how to fix this, but when we're using our XL-1s, we often see really bad lines on our video shoots, especially when the camera is moved or turned during handheld shooting or when bright lights/flashes go off while we're filming.

It's so bad in some shots it looks like horizontal bars of missing video across the image.

What can we do to reduce these scan lines, and what settings and/or film modes do we need to set inside of the camera to reduce them?

Thanks!

[Jesse Rosten]

Almost sounds like you're talking about Zebra stripes.
Do these lines appear in your recorded footage as well as your
viewfinder?

[John Harris]

Yep. Big time. In fact, moreso on tape when we review it at a later time. The lines aren't as noticeable when actually filming through the camera optics.

Here's a few stills which show what i'm talking about, once again they seem to get worse when the camera is in motion or when a sudden flash goes off.

Girl with lines across her face:

http://www.aiptasiafilms.com/uvs030731-005.BMP

Motorcyclist in motion:

http://www.aiptasiafilms.com/uvs030731-001.BMP

Riding a Mechanical Bull:

http://www.aiptasiafilms.com/uvs030731-018.BMP

[Jesse Rosten]

Hmmm...

From the looks of the stills you uploaded I've come to the conclusion that.... you were filiming a Harley convention? :)

Here's another question... are you using a TV monitor or the computer screen to view your video?

To me, the lines look like regular interlacing artifacts. When I take your pictures into Photoshop and apply the "Deinterlace" filter they disappear. If you are viewing your footage on a standard NTSC television monitor these lines shouldn't show up. If you view your footage on a progressive scan computer monitor, the interlacing inthe footage is much more apparent.

If this isn't an interlaced issue then I'm stumped. Any one else have any ideas?

[Jean-Philippe Archibald]

Yes, it is typical of frame grabs from an interlaced video. If you plan to diffuse theses clips on a regular NTSC TV, you should not have any problem. But you can use a deinterlace software to convert you 60i footage (60 fields or half frames / seconde) to 30p (progressive scan, 30 full frame second).

But your XL1 can do a kind of progressive scan. Put it in FRAME mode want the "scan lines" will disapear.

[John Harris]

Well, i'm using my computer monitor to do the editing. I just tried running some of the video through DVFilm maker which has deinterlacing features and it removes a great deal of the lines, but not all of them. It could be related to that, I guess what I really need to do is a test burn onto a blank DVD-R or hook up the S-video and see what it looks like on a T.V..

DVFilm maker can de-interlace the images and convert the files to 30 full frame progressive scan or 24p. I wonder which format lends itself to NTSC mastering in 16:9 the best.

Thanks for the help guys. 95% sure it is a de-interlacing issue.

Oh, and yeah. The shots were from a harley convention! Our working title is "Redneck Riviera" and it wouldn't be Myrtle Beach without filming bike week.

[Rob Lohman]

First I'm thinking you have a field reversal. Which program did you
use to capture the footage to your PC and what program did you
use to export the BMP files?

Keep in mind that in Premiere etc. you must import the footage
with LOWER FIELD FIRST!! Otherwise you WILL get a reversal.

The rest of the lines are interlacing artifacts indeed. You should
NOT see those on a regular TV. If you are only editing on a
computer and then outputting to tape of DVD you should have
no problems as long as you handle everything LOWER FIELD FIRST.

Outputting to web is no problem either since you are dropping
resolution and thus at least 1 field. If you somehow do want
fullscreen playback on a PC to work correctly you should de
interlace the footage or shoot in frame (semi progressive) mode
(which is what I always do).

[John Harris]

Actually, i've used two different programs to do the firewire capture of the videos: Adobe Premiere and Pinnacle. As far as the frame grabs, I think I used Ulead video studio because it has a simple interface for frame grabs.

The deinterlacing functions within DVFilm maker were able to remove most of the scan lines but there are a few shots where camera flashes went off that it won't deinterlace.

I think from now on we'll just shoot in frame mode with the camera. It's not a huge problem and it only affected a few shots, so i'll chalk it up to a learning mistake.

I never knew that Premiere needed to be set to "lower field first" or "lower frame first" when doing captures, but i'll try to re-capture the video where it's a problem and see if those import settings help.

Thanks guys!

[Rob Lohman]

I'm not sure Premiere needs to be set to that during capture, it's
been a long while since I used Premiere. Make sure Premiere is
setup for DV and if there is ever a field selection box make sure
it is set to lower field (there is no lower "frame") when doing DV
work in interlaced!