Video Render Question

btbrossard wrote on 10/21/2004, 4:37 PM

I have sort of a "dumb" question about video rendered in Vegas MS.

When I capture the video from my DV camera, the video looks great on the computer monitor.

After I do whatever editing I need and render the video with MS, the video looks to have thin horizontal lines running though it when I play the video on the computer monitor. If I burn the video to a DVD, it looks good on the tv and in the past that's all I've ever done with my videos so I never cared.

EDIT: After some looking around I found that I was seeing the interlacing of the video on the computer monitor. I do know what interlacing is, I guess I just wasn't putting the two together.

I'm assuming that if I render the file as progressive scan the lines will go away. Is this what others do when making a file for monitor viewing?

Thanks-

Comments

ChristerTX wrote on 10/22/2004, 5:20 AM

I have never seen this problem.
I render to the basic MPEG2 format and that plays fine on the computer monitor.
The progressive scan has not anything to do with the rendered file.

Christer

btbrossard wrote on 10/22/2004, 7:35 AM

I made a sample screenshot to show the what I was talking about:

http://thebrossards.com/sample.jpg

Sorry it's not the most interesting subject matter.

The left half is an avi file rendered with "lower frame first interlacing".

The right half is an avi file rendered with "progressive scan".

The rest of the render settings are the same. The lines are most visable in light areas when the subject is moving.

/Benjamin

Former user wrote on 10/22/2004, 7:45 AM

There is alot of information available about interlacing and computer screens.

Basically, a TV frame is made up of two fields, each 1/60th of a second apart in time. On a normal TV, this is how the frame is drawn. First one field then the second field and you have a frame.

A computer screen draws the whole frame from top to bottom. Since the video frame has fields that are 1/60th of a second time difference, you will see horizontal lines on frames with movement.

Some MPEG2 players allow for this by either playing only one field, or actually simulating a TV scan.

If you are wanting to watch this video on your computer, you can either use a Deinterlace filter, which will either show only one field or blend the fields, or you can make a progressive frame, which does a similar thing as the deinterlacing.

Dave T2