seeing through upper track'svideo at the edges

megabit wrote on 11/9/2008, 7:41 AM

To my horror I've found some bugs in my ready (i.e. downconverted to DVD from HD) video. Some B-roll events, sitting above the main video track in my Vegas project, do not cover completely that track's picture at the very edges - this is just several pixels wide "slot", or crack, through which I can see the lower track video - especially when it's brighter than the B-roll event.

What can it be? All source events are of course the same format (EX HQ 1080/2p)...I have done no cropping/panning, either.

Of course, this is only visible on a HD TV or computer monitors; the safe area mask in DVDA shows it's safe outside it - but with so many people watching DVD's on the PC's nowadays, it is a problem!

Back to post

Comments

megabit wrote on 11/10/2008, 9:28 AM

I have already investigated this, musicvid.

I suspected the see-through could be caused by a single-take track masking a multi-take track.

But the results of my investigation tell me it doesn't matter: I put a single-take event above another single-take event, and the down-converted mpeg still shows the artifacts in question.

Robert W wrote on 11/10/2008, 11:53 AM

I can't believe I am still trying to help here, but first of all I DID explicitly explain what the theory behind it was:

"The reason that you increase the numbers to do the crop is because you are increasing the size of the track not the project. It is like looking through a window and making everything in the room bigger."

Then you said:

"Thanks Robert. I tried it "my way" (i.e. as intuition told me - DECREASED te horizontal size), and got something closer to the proper aspect ratio.

However, is there a way to precisely calculate this "window" size, or do I need to rely on trial&error?"

And you said that after I gave you the exact settings to scale it to. If you follow the instructions I gave you, it will work. Yes it is the track motion option you need. You need to change the width and height in "position". If they are set to 1920x1080 as default and you take either number up you should see the video get increasingly cropped (i.e. get bigger). If that does not happen, then you are doing the wrong thing. Go back and start again. Follow everything to the letter.

megabit wrote on 11/10/2008, 12:17 PM

I did, Robert.

What I'll say now is very important to us all: nobody likes admitting he was wrong, neither do I. But yes, I WAS wrong.

The method Robert was suggesting from the very beginning of this (and another one) thread, is the right method.

Not only do I get the right proportions in my downconverted mpeg's; I don't see the leaking at their edges, either.

We're having the National Independence day in Poland tomorrow, which gave me one extra 24 hours before the dead-line comes, and I used it with success...

Thank you Robert. And I'm sure I'm not the only one who is satisfied with the output of this dispute.

However, this whole thing is not documented at all; SCS should either document it or make it automated, so that nobody gets in trouble when down-converting from HD to wide-screen SD, using Vegas own template!

PS Robert, one more thing if you please: when asking about "the theory behind your advice", I was only doubtful about the numbers themselves (1971x1081.5) - not the method. Using the actual HD and wide-screen SD aspect ratios, I tried to re-create these numbers, and I failed. Could you enlighten us how they are derived?

farss wrote on 11/10/2008, 12:31 PM

I too did try Robert's method but got wierd results. Clearly I missed something.
Perhaps seeing as how this has now been cracked someone could post a sample project. I guess the VASST site would be one place that comes to mind. Maybe two projects wouldn't hurt, one for PAL and one for NTSC.
I'll certainly go back and give Robert's method another shot. Once I get it to work I'll see if I can post the project file somewhere for future reference as I agree with Piotr, we should be doing this correctly if there's a simple enough way to do it.

Bob.

megabit wrote on 11/10/2008, 1:29 PM

BTW, the sizes 1971x1108,5 are still not perfect - the left frame edge is cropped properly and doesn't show any leaking, but the right one is just at the very edge - I can see it shivering.

Probably moving the frame to the right by 1-2 pixels should be enough, but it's also possible it would reveal the left edge - so 1972 might be worth trying, or moving by 1-2 pixels to the right, or the combination of both...

Anyway, I'd like to once again thank Robert W., Bob (farss), and all others who were trying to help !