Menu Jags

Dreamline wrote on 8/12/2007, 3:12 PM

Hello,

I did a test with the same video with titles. I used it twice on a single DVD. I used the video as backround for the menu and as a video to be played off of the DVD. The same exact video looks much better when it is not USED as the backround. The letters are smooth and good looking. However, when the same video is used as the backround the letters are jagged.

This leads me to believe that DVDA makes a video with titles look worse than if that same video is just played not as the backround.

Has anyone noticed this too? What gives?

Comments

bStro wrote on 8/12/2007, 4:19 PM

What kind of videos are you using? DV AVI? MPEG2? Divx?

Are you adding anything to the menu background within DVD Architect? Graphics? Thumbnails? DVDA-created text?

When you add additional content to a menu background -- graphics, thumbnails, text -- in DVDA, that means it will have to re-encode your video. That's the law of DVDs -- a menu is a single, encoded video object (with optional audio). Depending on what kind of file the background is, this can result in encoding artifacts such as "jags." It's going to be even worse if the video is already highly compressed, like MPEG2 or Divx.

The best courses of action is to either a) create your menu background (including all titles, thumbnails, etc) entirely in Vegas or other editor and encode to a DVD compliant MPEG2 so that DVDA doesn't have to re-encode; or b) render your background to DV AVI, put that as your menu background, and add whatever content you want to add in DVDA itself. By using one of these methods, you are either a) ensuring that DVDA doesn't have to mess with the quality of your video or b) giving it the best possible image to work with when it does.

By contrast, the videos you add as regular media items, assuming they are DVD compliant, do not need re-encoding because you're not adding anything to them in DVDA.

Rob

ECB wrote on 8/12/2007, 4:28 PM

DVDA will recompress your menu background mpeg video to build the composite of the background video and the letters. Recompressing the mpeg will degrade the quality. You can avoid recompress and the degradation by building the composite title in vegas the using progressive scan when you render the mpeg. YOu ccould also use the dv file for the menu background video and avoid the mepg degraduation. In DVDA you can go to File/Optimization and see what in the menu... is being recompressed. HTH

Ed

<Edit> Sorry for the redundancy. Should not get a cup of coffee during a post. :)

Dreamline wrote on 8/12/2007, 8:29 PM

I don't think there is any encoding going on, since the video file is mpeg2. I am adding one thumbnail. This is what I am doing.

I have a video of a blurry waterfall that has the title The Wedding of... It is an mpeg 2 video prepared by Vegas and it looks great.

Then I perform a test where I import the video in twice to see which was looks better. I import it as backround for the main menu. On that menu I make a button that links to a 2nd import of the same video.

I prepare the DVD in seconds with no re-rendering of any kind. I make the DVD. When I test it the the letters on the video of the menu screen look terrible, but the letters looks great for the video the button leads to.

Is there re-rendering going on without me being aware?

I'm confused why the same mpeg2 file would looks so remarkably different. How could the same video look so good and look so bad there was not any rendering going on.

How does DVDA superimpose the button over the backround video without rerendering it, even though it is a mpeg 2 file. It doesn't make sense to me.

bStro wrote on 8/12/2007, 9:53 PM

I don't think there is any encoding going on, since the video file is mpeg2. I am adding one thumbnail.

If you added a thumbnail, then DVDA re-encode the menu content. The encode was probably just fast enough that you didn't notice. I would assume that the menu is relatively short (under a minute?), which wouldn't take long.

Also: Waterfalls (and blurry ones at that) require a lot of bits because there is so much random movement. So, sending video of that through two encodings is really asking for trouble. ;-)

Rob

Dreamline wrote on 8/12/2007, 11:59 PM

Thanks for the help. I understand now and have everything looking great. I was rendering the video for the menu twice by mistake.

Thanks again.

ECB wrote on 8/13/2007, 4:19 AM

FishEyes, In DVDA you can see how DVDA is processing your menu... Go the File/Optmize DVD and click on your menu in the left column. Click on Video and you can see if DVDS is recompressing your video.

Ed