The Horrors Continue

Movick wrote on 6/14/2004, 8:34 PM

I’ve been experiencing a host of problems with VV5 on this 40 minute instructional DVD I’m authoring. First the “combing” effect issue I’d submitted earlier, now a horrid flickering problem. I am using still images throughout this project for bumper screens, product shots, etc. I created these images at 654X480 and insert them into the VV5 timeline where needed. After I render, and create a test DVD, I see considerable flicker in many of the still shots on playback. Some of the stills dynamically reduce in size as picture in picture windows. Additionally, I’ve reduced the overall size of the main video window by about 10% or so to reveal an underlying “Digital Juice” type background (for effect only). I added a simple pinstripe border around the main window to define it from the background, and on playback, the edges of the window appear wavy and fluttering (particularly the vertical lines). I also notice that the main window appears off center on the screen.
I spoke to tech support about the earlier “combing” issue, and they suggested rendering from the original timeline at full screen (720X480) to a progressive scan .avi. I next rescale the rendered avi and drop it over the animated background. I render this file as a MPEG-2 (NTSC DVD template). I had already selected the “reduce interlace flicker” check box of the troublesome clips in the original timeline, and this really does not significantly improve the flicker problem. Does anyone have any suggestions for minimizing this flicker – especially the bordered edges of the main video window, which appear distorted?

Thanks in advance,

Movick

Comments

PeterWright wrote on 6/14/2004, 9:16 PM

If the border lines are very thin they will always cause flicker, so you could try making them thicker, and apply a little blur.

John_Cline wrote on 6/14/2004, 9:40 PM

Thin lines will cause flickering and so will too much detail in a scanned image so try Peter's suggestions. Make the lines fatter and try adding a little bit of blur to your images.

Regarding the wavy issue, it's likely that the television on which you are monitoring your work doesn't have a well regulated power supply and the brightness variations in your images are causing the TV to "flutter." TV's don't like sharp horizontal contrast changes. This needs to be dealt with in your production because your audience is going to be viewing your DVD on the same type of TV's. As far as the centering of your image is concerned, all TV's are off by some amount and there isn't anything you can do about that.

John

Movick wrote on 6/15/2004, 1:28 AM

Thanks for the suggestions guys. I am still however quite unclear as to why my stills are flickering when played back on DVD. I see all types of productions on broadcast daily, which exhibit stark, often complex contrasts between image overlays, and they look crisp and clean.
There has to be a method to address this issue without reducing the quality of the image by blurring. Am I to understand that I should blur every still that appears to flicker? Wouldn’t the video look abysmal in this instance? May I ask to which blurring process you refer? Any other suggestions… I’m running out of time and steam on this project.

Thanks again,

Movick

PeterWright wrote on 6/15/2004, 1:36 AM

I was only suggesting thickening/blur for the line border.

Unless they contain lots of intricate lines or non-kosher colours/contrasts, stills should not flicker - I would double check those - if video stills, are they deinterlaced?

farss wrote on 6/15/2004, 4:33 AM

One trick I've used to clean up SOME still images is vertical guassian blur. This makes the lines more than one scan line thick without fattening them in the other direction..
If the overall iamge in flickering something is wrong. You should be able to see this on the scopes. During a still they shouldn't move.