I have an aliasing type artifact that I cannot remove or fix

[arcorob]

I have a bug in some captured digital video. When rendered to MPEG 2 (or even in the avi) I get a cross line effect like a jagged edge across a persons front.

They are wearing a tuxedo, approaching the camera and walking off to my left. As they are about toi exit the picture I see an effect or artifact that looks like this

----------
---------
----------
---------

In other words their clothes become a series of UNEVEN bars instead of just a flat outline.
Is this aliasing ? How do I get rid of this.

I have captured via digital video into computer via firewire.
Vegas video for editting.
I have tried both TMPGennc and Mainconcept for rendering to mpeg 2. Same effect.

With TMPGenc I set for the very slowest motion compensation. 4500 KB per sec, CBR, 9 bit precision (have tried 10) Am i missing a setting ? This effect ONLY happens on this motion. No other motion however,
on another video one time, I had a startling scene where a maid of honor goes to walk offscreen and she fades to transparent before she gets offscreen, just like a ghost.

Even viewing the AVI for this one, I see lines that I just attributed to interlace thinking they'kll come out in the wash so to speak. Not so. They got MUCH worse as an MPEG.

HELP....and thanks

[Gazorgan]

Sounds like Interlacing. Try changing your field order when you encode? MPEG2 is interlaced, so definately don't de-interlace.

[DJRumpy]

It could also be field order (although TMPGenc usually doesn't guess wrong). If its video from a CAM, then it's bottom field first.

[arcorob]

Yes, i have read as much as I can on this. It would seem that the field order is correct (lower field first) and I do not have these artifacts anywhere else. I read what Vegas had to say and a host of others.

Here is where it gets tricky. I could TRY reversing the field order but do not think that is the answer. Anit-aliasing filters seem to be BEFORE the fact, that is prevent high frequencies from being generated beyond pixel ability. Thus creating things that are not there (the ghosting lady ?)

What I am really afraid is or might be happening is a field order plus fram problem

Example
Frame 1 is made of
Lower field 1
Upper field 1

Frame 2 is made of
Lower field 2
Upper filed 2

Both would look fine.

But if they cross and you get
Upper field 1
matched with
Lower field 2

you would get that motion aliasing effect sort of like below when motion occured

11 22 33 44 45 66 77 88

frame 5 is corrupt because it is really using two frames incorrectly. Uggg

Anyone know how I might CORRECT this ?

[DJRumpy]

I only suggested it as a possibility. I agree with Gazorgan. It's probably an interlacing artifact. I don't suppose you could post an example somehwere. We would only need a screenshot/capture to see what it looks like. A tiny clip would be even better.

[arcorob]

Sure ..WOuld love to !!! I will do so after work but do you want to see the mpeg 2 or avi screen shot or both ?

[DJRumpy]

Whichever shows the artifact your describing. AVI is fine.

[arcorob]

Okay, I figured out what caused the artifact and it SUCKS. Was able to correct, but not as I wanted.

It is not field order or anything, it is a GENUINE Vegas Video 4.0 bug.

One of my camera's shows a small circle of the wide angle lens I use if I am pulled all the way back. SO I use vegas PAN and CROP. Just like I use alot of Vegas tools. Basically its like zooming in so the black edge disappears. For some reason, this function created an Artifact HERE. I use it elsewhere, no issues. But that spot due most likely to the HIGH input (sky , grass , colors, et) sigh.

I found out by checking the original captured avi. It was perfect. as I had already rendered the whole dang wedding, I took the GOOD clip, overlayed the bad part , re-rendered and its fine.

So good news, its fixed. Bad news, I have a potential problem.

[vhelp]

hi arcorob,

You figure it out before I could answer you

This seems to be w/ most cams that are set to 16:9 recording. It also
effects the LIVE (when not recoridng to tape) shots as well. So, you can't
really go blaming the tape either.

I am still puzzed by this issue. But, when I swith off the 16:9 mode of my
cam, the issue are GONE, and the video is sharp (w/out jaggies you described)

I did notice at times, if I zoom in/out, I could manuver past this, but could
get tricky when you are zooming in and hit those jaggs and you don't catch it during recording So, I find it tricky at times. But, I'm not too
sure that this is working. I have to do some more testing with this to be
absolutely sure

I suspect that most if not all cams share this issue. However, I don't think
that most peoples are actually realizing this. I think they are either ignoring
it and brushing off to normality, or they are just not catching it (yet)
Now is the time to wake up upon this issue.

@ arcorob,
..So, you're not alone on this problem.

-vhelp

[arcorob]

Thank you !
Here is my exact situation.

I have three sony's. The wide angle lens is really made for the TRV340 however, I do use it on the TRV140.

If I am pulled all the way back (no zoom) I get a small black curve upper left and upper right that is because the lens can see the screwed on wide angle lens. If I zoom slightlight it doesn't.

Anyway, if I forget to zoom, Vegas Video has a PAN and CROP funtion that lets you do thinks like zoom, move in , even fake a slow zoom shot when you did not zoom.

So to remove the little black curves, I use that and ZOOM the frames slightly on that clip. But for some reason, Vegas hosed it but good.
Right on the avi. I checked the original captured AVI and it was fine.

So vegas has a bug Uggg. One I have to be carefuloff. It is really a nasty little bug and I bet they knew about it because they describe it in teh guide (when an upper from one frame is merged with a lower of the next during motion) oh well..Thanks to all !