Video capture Jaggy Motion Blur edges- fixes?

ken c wrote on 4/28/2004, 10:27 AM
Hey Vegas editors... quick question for you experienced folks:

look at my blurred hand in this screencap... why does it blur - ideas?

http://www.daytradingu.com/semblur1.jpg

do you know know What causes an image being captured on video to blur when it's moving like this?

In trying to capture source DV via firewire into Vegas 4, I get jagged edges during the capture.. same issue w/external capture card,

whenever I'm moving, there's a fuzzy/motion blur type of minor distortion around the edges of me when I or my hand moves etc in the source video..

in this photo, you can see that the image of me standing is fine, but the hand is all fuzzy, vs clear... this also happens to other edges, whenever I'm in motion...

when I'm standing and talking, no distortion appears..

ideas as to how to a) fix this for current capture project and/or b) avoid that blurring in future video captures?

this was done professionally by a videographer using a high end sony camera, on the source dv it looks clean, but capturing to pc causes jagged edges (capturing on high end P4 2gig pc, to a 2nd hard drive etc)..


thanks,

ken

Comments

Chienworks wrote on 4/28/2004, 10:41 AM
It's interlacing. The video stream consists of two fields for each frame, 1/60 second apart. Each field contains every other line of the image. So, when you move, the first field captures all the odd lines and the next field, 1/60 second later, captures the even lines after your hand has moved slightly from where it was in the first field. When you combine both fields together on the computer screen this time difference results in the combing affect you see around your hand.

This is completely normal. Do not panic.

When your video is played back on a television the effect will disappear because the television will again show the fields separately 1/60 second apart. This is only a problem if you view it full resolution on a computer monitor. If you're going to be rendering full frame size (720x480 for example) for computer playback then you will have to live with it or de-interlace. If you render for TV or render half-size for computer playback then it's not an issue.
ken c wrote on 4/28/2004, 10:58 AM
Hi - hey thanks a bundle Chienworks...! I was starting to panic there ... :p

I'll have to do what SPOT / DSE/ David Spotted Eagle says in his (excellent) vegas 4-dvd tutorial, eg get an external CRT monitor, so I can see what the final video stream will look like on a tv monitor.. vs just looking at it on the pc crt...

thanks -- I owe ya!

ken
jccoulter wrote on 4/30/2004, 11:53 AM
I have had the same problem for a while now. I typically reneder my video in MPEG2 and create a DVD for playback throught a projector on a large projection screen at Church. This problem is very noticable in the final production when viewed on the large screen. Is there any way to eliminate it in the final render to DVD?
PunchNBurn wrote on 4/30/2004, 2:40 PM
I have a similar problem. I am getting flicker with STILL images. Why is there flicker in still images? How do I get rid of it? The DeInterlace setting has no effect.

Thanks.
farss wrote on 4/30/2004, 4:55 PM
Have you tried playing a commercial DVD throught the same system and if so how did it look?
This problem could be coming from a number of issues so we'd need more specific info:

1) Are these truly interlace artifacts, they look like combs or fine teeth on the vertical edges of moving objects.
2) Maybe your seeing macro blocking as the bit budget is too low for the material being encoded.
3) Maybe your seeing DV comprssion artifacts, cannot do much about them although a VERY slight amount of blur before encoding may make it look better.
4) Maybe the projector is displaying progressive scan and you're feeding it interlaced material.


If you can try playing back a cmaera tape, even from the camera into the projector and see how that looks. Keep working down the workflow chain using just a sample bit of video to isolate where the issue creeps in. A little science goes a long way in this game,
corug7 wrote on 5/3/2004, 7:02 AM
I have had this problem quite a bit. It is not normal interlace and in fact leaves the final production looking very jumpy, and capturing stills requires using a de-interlace filter, or else the frame looks like two blurring together, like pause on a two head vcr. I'm wondering if maybe fiddling with the capture settings (odd/even field first, etc) will make a difference. I'll post my findings.
ken c wrote on 5/3/2004, 9:42 AM
one helpful suggestion from one of the folks on another board is to use the windows media encoder to deinterlace, not the vegas one..

eg output vegas in uncompressed avi, then render using windows' media encoder (free) and use the deinterlace option..

ken