Problem with fuzzy preview on 30" monitor OUCH!

xberk wrote on 4/10/2009, 11:34 PM

Is there a maximum size to the preview window at which point the images starts to fall apart? .. Most of us will not encounter this problem but my daughter uses Vegas 8.0c and recently got a 30” Dell 3008 LCD monitor.

Vegas looks great on it (lots of real estate) but the preview window is SOOOO large it seems to turn certain video clips into FUZZZZ. She actually has to reduce the preview window in size to make it look decent. The clips that seem the worse are standard DV clips shot on a Panasonic GS250 and captured with Vegas 8.0c in the standard AVI format. Here's what the larger preview window looks like. But when the preview window is reduced it size it it looks like this.

Everything seems to render normally, but she would love to have as large a preview window as possible and it’s disturbing to look at the choppy image. Would there be a reason only certain clips behave this way? Could it be a bum setting somewhere? Checked all the preview window settings and project properties. Nothing seems to help. Has she hit some sort of limit? Any thoughts?

Comments

farss wrote on 4/10/2009, 11:42 PM

She has the preview window set to Preview Auto. Try increasing the quality to Best Full. You could also try turning Off Scale Video to Window by R-Clicking the Preview Window except that will prevent Preview being any larger than pixel to pixel which will probably look pretty tiny on a 30" monitor.

Bob.

Grazie wrote on 4/10/2009, 11:48 PM

You've got Preview (Auto) selected, I am guessing this is 'cos you need more frame rate? Try Preview FULL. Then Good (Auto) then Good full. Is this the only monitor? If it wasn't then you could try the 2nd Monitor setup OR even have the Preview pass to an External Monitor.

The "fuzz" you are alluding to is the de-interlace of fields coming into play.

Grazie

Tim L wrote on 4/11/2009, 7:11 AM

Much of the story is told in the "Display" numbers shown to the lower right of the display window. In the "good looking" image, the Display pixels match the project size, at least as far as vertical resolution of 480. In the "bad" picture, the Display height is bigger than the original source, so things have to get interpolated.

What actually looks bad about the bad picture though is the interlacing, as Grazie suggests. Look at the "Preview" numbers below the display. In the "good" picture, the preview image is 360x240, This means that Vegas is only displaying one field of the original image (just the even lines, or just the odd lines). It calculates a 360x240 pixel image internally, then expands that (line doubles it) to an 872x480 image on the display. So the image is actually lower quality (less detail), but looks better because it avoids the interlacing artifacts. (All this is presumably NTSC.)

I'd always thought that "Preview" quality always used just one field for the display, but that must be true only as long as display size is less than or equal to project size. Once you exceed that, it must start using both fields. (Maybe "Draft" always uses just one field.)

Also, as to why some clips look better than others -- it all depends on the amount of motion. If no motion in the frame you are looking at, the image that contains both fields will look sharper and more detailed. This looks bad when you do have motion in the image because the image for the even lines and the image for the odd lines where taken 1/60th of a second apart, but are "combined" into one picture in the displayed image.

Solutions? Probably what Bob suggests -- trying different settings. However, I think that using "Good" or "Best" settings are always going to use both fields of the frame, and consequently will always show the interlacing artifacts.

Tim L

Addendum: The solution to get rid of of interlacing artifacts is to use one of the "Half" settings: "Preview (Half)", "Good (Half)", "Best (Half)". Then Vegas will use only one field to create the display image, no matter how many pixels you stretch the actual display window to.

However, using a "half" quality display might not be very satisfying in the long run, because of the loss of detail and crispness in the image. Maybe another solution is to just get comfortable with the fact that this display issue is normal, its the result of interlaced video, and is only an issue when you stop on a frame with motion in it.

So find a solution that works best for her -- whatever is least distracting to her and lets her focus on editing rather than the display.

xberk wrote on 4/11/2009, 9:11 AM

Thanks guys. I'll pass on this information. I'm assuming this will be less of a problem with higher resolution video shot at higher frame rates. Understanding the de-interlacing, interpolation etc is not intuitive. But it's probably worthwhile to understand it.

We expect so much today in an editor. Real time everything right down to the color correction. I remember the days of film editing when we'd be using a b&w workprint and one track at a time on a moviola. Dissolves were grease pencil marks. A simple superimposed title was "an optical" that had to be sent to the lab. I think my daughter will get past this little problem on her HUGE monitor.