HDV Capture Artifact (Interlace Lines / Horizontal Bars)

intersilmultimedia · Post by **intersilmultimedia** » Thu Feb 21, 2008 9:45 pm

When I capture HDV I get what I can best describe as alternating horizonal bars or interlacing lines. There seem to be about 120 lines total or two sets of 60.

It happens on moving things, and it occurs so often on almost anything that moves. The artifact does not seem to show up on the camera monitor when I simply play the tape (though it's hard to be 100% sure it's not there, as the camera playback monitor is small), so I think it is being introduced by MediaStudio Pro.

I am capturing all video with Video Capture 8.0 using it's default settings for my camera.

Any ideas why this is happening?

Here is an frame grab of the problem:

If the above does not show the image, or you want to see a bigger version with more detail, you can go to this link:
http://www.facebook.com/photo.php?pid=3 ... 1130568685

I am using:
* MediaStudio Pro 8.00.0028 Trial Package
* Sony HDR-FX1 (recording in HDV mode)
* Windows XP Pro SP2 with 3Gb of memory, a video card, and a hard drive with plenty of room

troppo · Post by **troppo** » Fri Feb 22, 2008 4:30 am

you field order settings are reversed. You have either top/upper/first field or bottom/lower/second field. Change to the other one and it will work fine.
(for some reason I think the field order on HDV opposite to DV)

Nice informative post by the way.

intersilmultimedia · Post by **intersilmultimedia** » Fri Feb 22, 2008 4:57 pm

Thank you for the reply.

I couldn't see any way to change the field order settings during capture, so I worked with that (and other settings) in MediaStudio Pro proper. I tried various settings. Initially, the clip was set to Upper Field First as was the project overall. This seems to match the actual format of the clip. My export with the problems was also the default settings and matched the clip settings.

Since I have this problem with all my projects, I created shorter test clips to try things out. When I import the clip, just before clicking Open, I choose Info..., and MSP tells me the clip is MPEG-2 Video, Upper Field First.

In any case, here are the changes I made, each time creating an MPG video file and watching the results in Window Media Player:

Clip to Upper Field First, Project at Upper Field First
Bad (horizontal bars appear)

Clip to Lower Field First, Project at Lower Field First
Worse (horizontal bars appear even more prominent)

Clip to Upper Field First, Project at Frame-Based
Worst (horizontal bars appear very prominently)

Clip to Upper Field First & Deinterlace, Project at Frame-Based
Great (no bars)

So the solution seems to be set the Clip | Media Source Options to Upper field first (the default) and check Deinterlace. Then, change the project overall to frame based (Project | Project Settings choose Edit¡K go to the General tab and change Frame type to Frame-based).

Thanks for pointing me in the right direction, troppo. I now have two follow-up questions:

I am only playing my clips on a digital computer monitor and I do not have a HD monitor on which to review things. If I played my interlaced (1080i) clips that were showing the horizontal bars on a interlace monitor, would they not show up? And vice-versa, will my frame-based project look bad on an interlace monitor?

Also, does my quality suffer in the process of converting the clips to deinterlace and the project to frame-based?

troppo · Post by **troppo** » Mon Feb 25, 2008 3:38 am

Hmm, interesting.
What format HDV are you using? There's interlaced and progressive recording formats. Your capture format should match the camera recording settings.
If it's 1080i then it's interlaced. 1080p is progressive.(frame based)
I'm sure there must be a way to change the capture settings somewhere. I had this exact same problem when I first tried to capture HDV with MSP8.
Good luck.

robtywlak · Post by **robtywlak** » Tue Feb 26, 2008 2:16 am

When displaying any interlaced source on a computer that is natively progressive interlacing artifacts will be visible unless your display matches exactly the source properties and is viewed full screen.

One option is to set your preview window to be either 1/4 or 1/2 scale and you will not see the interlacing.

Another is to de-interlace the video by setting the media source options on the timeline.

If the intent is to maintain 1080i output then do the first option and match the field order to the source - HDV appears to be upper field first while DV is lower field.

The lines in your preview image are a combination of interlacing and image scaling causing the banding effects.

Hope that helps.... now if I can just get the Damn Playstation 3 to read a dual layer disc I will be set

It plays native HDV files at full resolution and bitrate.... one DVD4.7 gig holds 24 minutes.

Regards,

Rob

intersilmultimedia · Post by **intersilmultimedia** » Thu Feb 28, 2008 6:04 pm

I'm shooting on a Sony FX1, which only shoots interlace at 1080i. As I am not sure where my final material will end up, I think I will create two versions of every project. One will keep it 1080i. The other will be a non-interlace version where I use MSP to convert it.