ragged edge

drb05 wrote on 3/17/2005, 10:44 AM

Hi all:
Lately I have realized that vegas has been introducing some defects in my video. It is hard to explain without attaching an image to show what exactly is happening. However, i will explain. please help.

I use miniDV. Capture video using vegas in avi format. The video looks fine. But when i render it as mpeg2, see ragged edges objects in the video appearing often. I mean, say you are looking at a face, the curvature appears smooth, then in an instant it become jaggedy appearance and then goes off. Imagine looking at a straightline. This happens often throughout the video. But does not remain constant.

Can somebody explain why this is happening? and how to prevent it?

thanks,

drb

Comments

craftech wrote on 3/18/2005, 5:44 AM

Actually there are two current threads on the subject of "aliasing". They are here and here.

John

ericd2003 wrote on 3/22/2005, 8:47 PM

I have the same problem and can't seem to find the answer as well.

chaboud wrote on 3/22/2005, 8:58 PM

Where are you playing this footage back?

On what type of device?

johnmeyer wrote on 3/22/2005, 9:30 PM

But when i render it as mpeg2, see ragged edges objects in the video appearing often.

I have a hunch. When you render to MPEG-2, what template do you use? Do you use the "Default Template?" Or, do you use one of the "DVD Architect" templates?

My hunch is that you are using the "Default Template." Sony made a horrendous mistake, which they keep failing to correct. Any time you start Vegas, and then select MPEG-2 as your rendering format, they always present the "Default Template" as the option. You are therefore forced to select something else. The problem is, the Default Template -- to put it mildly -- STINKS! You will find, that if you select the Default Template, then select Custom, and then click on the Video tab, that the Video Quality is set to 15, whereas it is set to the maximum (31) when you select any of the DVD Architect settings. The difference in quality between 15 and 31 is not subtle, and when it is set to 15 you will definitely get the horrendous artifacts you are speaking of.

The only reason I can think of why Sony would force you back to the Default Template every time, and why they would make a Default Template that produces such lousy video is marketing: The lower quality settings encode MUCH faster, and therefore they must have hoped that the brain-dead reviewers would simply write down the fast encode times and give Sony the edge.

Whatever the reason, try encoding using the DVD Architect NTSC template (you'll have to encode your audio separately), and see your problems go away.

Also, what average bitrate are you using for your MPEG-2 encoding?

drb05 wrote on 3/30/2005, 6:43 AM

Extremely sorry for the delayed reply. Got sick.

Thanks for the replies.
I am using my own settings as per suggestions from this forum to my previous threads. It is
Variable bitrate, two-pass
Field order: interlaced
7,500,000 Max bps
6,000,000 Ave bps
2,000,000 Min bps
Video rendering quality: best
NTSC
All other settings are untouched/default.

For 'big-time's software, I am surprised why it has this problem. Lately I bought a sony computer which has 'click to DVD', seems simple enought software to create DVDs. I am going to try that also and see.

The problem is, avi files do not have that ragged edges but mpeg2 has. One can clearly see this when there are straight objects like a stick or outlines of a face.

I am also looking into aliasing threads suggested by other user.

(ON a different note: can somebody help me out in finding the 'theme' files of click to DVD software. I liked those and would like to use them with DVD architect, but unable to locate the files in click to dvd programs files folder. What extensions do they have. the reason I am asking is that click 2 dvd does not allow to add more text boxes on the menu, so it is kind of a pain to have everything in the title and same font size)

Thanks for the help in advance.

drb

johnmeyer wrote on 3/30/2005, 4:33 PM

1. If you view the video on your computer monitor, you will see jagged edges because your MPEG-2 is interlaced, but your computer monitor is progressive. You MUST play back the results on a TV set before you know if you have a problem. This is NOT a problem with Vegas. The reason you don't see the artifacts in the Vegas preview window is that the window is not full screen, and therefore doesn't show all the scan lines, is therefore not interlaced, and doesn't have the problem. If you can burn a test DVD using a DVD-RW and then play it on your TV's set-top DVD player, that is the best way to see your final quality.

2. Another possibility is that you have chosen the wrong Interlace setting in the MPEG-2 encoder, although you would have had to change it to get it wrong. The Field Order for encoding from NTSC DV video should be "Interlaced, bottom field first."

B.Verlik wrote on 3/30/2005, 4:44 PM

If the artifacts occur mostly when the camera is panning or an object in the video is moving quickly, it's most likely the field order is backwards. Bottom field 1st is normal, but make sure that your source (camera) is the same too. If you're camera is Top field 1st (pretty rare), then you need to change you're settings to "Interlaced Top field 1st" (in the mpeg custom settings video tab).