What's up with VMS8 Preview?

rem715 wrote on 8/14/2007, 9:43 AM
I recently upgraded to VMS8 to start editing in HD with footage taken from a Canon HV20. I'm glad that, at least, the hd footage is now pretty smooth in the preview window. However, my head is still spinning from the thread on the HD rendering post and the bug that VMS8 has in rendering 1080 (60i).

While adjusting the project settings for HDV footage shot in 60i, I noticed that the image in my video preview changed considerably. When set to the HDV 60i template, the image in the preview window became very soft, almost out of focus. When I switched the template to 720 (I believe its 30p), the preview image looked the sharpest. On all other templates, including DV widescreen, the image softened up again.

I then loaded up some standard dv widescreen footage and found the same issue. The video preview looked soft and out of focus on all settings except using the 720 template. This is strange and really makes the footage in the preview window look like it was shot out of focus. Is this another bug in VMS8? BTW preview settings are in "draft" and "auto" mode. I tried the other settings including "best" and found the same issue.

Comments

Eugenia wrote on 8/14/2007, 10:34 AM
What you are comparing is resize algorithms and not how Vegas really "see" your footage.
Here is how you will see the real image in the preview window:
1. Click on the properties and choose the correct template (e.g. HDV 1080/60i). Also, select "Best" from the quality drop down.
2. In the Preview window, instead of using "preview quality" select "Best (Full)". This will give you the best quality at 1:1 size.

Now, I recommend you connect a second monitor on your PC, you configure it, and you use that for a preview. It will fit much more of your footage.
rem715 wrote on 8/14/2007, 1:10 PM
Thanks for the comments Eugenia.

Ahh. . . your suggestion for a second monitor is a good one, however, my wife would be a bit resistant to more equipment for this, er, little hobby of mine.

While adjusting the settings last night as you suggested, albeit in auto and not in full, since this is the way I will be previewing the footage while editing, I did see the expected increases in quality when adjusted to Best. However, using the 720 template still resulted in a much better image than the HDV 1080 template even at Best.

I understand that this not the way vegas sees the image since I rendered and got the expected superior image from a 1080 render, but it is the way I see the image while editing and it looks like it was shot out of focus and not a condition I want to work with. At this point, the most obvious work around is to just work using the 720 template for all my editing and change the settings to whatever resolution I want upon completion for rendering.
Eugenia wrote on 8/14/2007, 1:19 PM
I think the "bug" is that Vegas first resizes and then sets the aspect ratio, and so quality is decreased when viewing in 1080i. But in the 720p case they don't have to adjust the aspect ratio, because for 720p it's 1.0000 square pixels.

So yes, there is a minor bug if what you say is true about 720p being sharper in the previews, and the bug is that Vegas FIRST resizes and THEN sets the aspect ratio and so this results in worse quality. The correct way to do this is to first set the aspect ratio to 1.3333 and then resize to fit in the preview window. Otherwise, you lose quality, as you observed.

EDIT: I just tried it and indeed, for 1080i 1.333 aspect ratio videos, 720p looks sharper than 1080i in the preview window. I am 99% sure that what I said above is the culprit.

EDIT 2: It doesn't seem to be the culprit, because even for 1.0000 square pixels videos, the 720p preview is always sharper. I guess, something else is going on.
Ivan Lietaert wrote on 8/14/2007, 2:14 PM
Eugenia, can you confirm you can connect a second screen to VMS8? I thought this was a Vegas Full feature.
Eugenia wrote on 8/14/2007, 2:17 PM
The ability was added on VMS8. Let me snap a picture of my PC setting. Check again here in 10 minutes.
Chienworks wrote on 8/14/2007, 2:23 PM
Part of the reason that 720 looks better in the preview than 1080 is because it isn't reduced as much.
Eugenia wrote on 8/14/2007, 2:26 PM
http://osnews.com/img/vegas/vegas.jpg
You connect the second monitor, you right click in the preview window, you go to its preferences, and then you setup there the second monitor. To enable the second monitor on and off, you then click one of the icons in the preview window.
Eugenia wrote on 8/14/2007, 2:32 PM
Chienworks, this is not true. Both preview images have the same size and so there is no reason why they should look different. If anything, the 720p image should look worse (not the other way around), because of the lower resolution that is then extrapolated to the preview window. And yet, it looks better than 1080i.
Chienworks wrote on 8/14/2007, 7:02 PM
"Both preview images have the same size"

That's exactly the point.

"and so there is no reason why they should look different."

There is every reason for them to look different.

"If anything, the 720p image should look worse (not the other way around), because of the lower resolution that is then extrapolated to the preview window."

The resolution is the issue. The 720 image is modified less to obtain the smaller preview. The 1080 image is modified more. More modification means less fidelity to the original.

"And yet, it looks better than 1080i."

Exactly. Nice to see you agree.
Eugenia wrote on 8/14/2007, 8:56 PM
You are having it wrong. Are you actually a programmer? You can create HIGHER quality mini-views of an image when the source resolution is higher, because you have more *information* to build a better mini-view. And so, logically, the 1080i preview should be of higher quality of the 720p one. But it's not.
rem715 wrote on 8/15/2007, 8:37 AM
I would add that on my machine, using sd material in vms8, the 720 template looks superior to both the 1080i template and the DV and DV widescreen template (which is only 400 +/- lines, correct?). These templates make the image seem soft and out of focus. However, the same sd material previewed in vms7 using the DV template does not have this problem, the previewed image looks crisp.

So this makes me think there is a problem with vms8's preview.
busterkeaton wrote on 8/16/2007, 6:59 PM
you're confusing still photo data with video data
Eugenia wrote on 8/16/2007, 7:10 PM
There is no difference. The more data you have, the better mini-preview you can create.
rem715 wrote on 8/16/2007, 7:17 PM
Sorry, I don't think I'm confusing video with stills. I'm talking about the quality of video running through the preview window in vms and how that video looks much worse in vms8 than in vms7.

In order for the preview video to look good in vms8, i.e. comparable to vms7, the project has to be set to a 720p setting. If I use any other setting other than that, the video looks unaccepably soft.



Eugenia wrote on 8/16/2007, 7:26 PM
Yes. It is a bug. But a minor one IMO.
4eyes wrote on 8/16/2007, 9:31 PM
It would be helpful to post your computer specs. (P4-3.2Ghz, Core-Duo, Core2-Duo/Quad ......)
You may be alittle under powered for HD previewing & editing. A fast computer may yield totally different results.
Eugenia wrote on 8/16/2007, 9:39 PM
Actually it doesn't. This is just a VMS resizing bug. A pixel off during calculation so the division has a remainder, resulting in the algorithm trying to compensate and it resorts to softness. The only people who can fix this (minor in my opinion) bug are the Sony engineers. There is nothing else we can do here.
4eyes wrote on 8/16/2007, 11:25 PM
My VMS 8 Plat isn't performing as the above users posts.
The best previews are when my "Project Properties" equal the source videos properties.
In most cases this is HDV1080i(60) UFF.
I preview on & off between a 2nd lcd & a Sony hdtv monitor (crt), component or dvi.
I do have a HD Certiified video card in this machine.

Maybe I'm not being picky enough? But my previews are certainly not even close to being termed un-usable (posted above). Even at the lowest setting.
Still interested in his computers cpu speed and video card used to pre-render a preview on the fly.
rem715 wrote on 8/17/2007, 12:22 PM
As requested by 4eyes, my pc specs are: 1.5 GB Ram, P4 524 / 3.06 GHz, GIGABYTE GeForce 7600GT 256MB DDR3 PCI Express video card

My processor is my weak spot, however, my above described issue occurs (and is possibly worse) with sd material so I'm not sure that is what is to blame. 4eyes' results are what make sense and are what I would've expected on my machine. I'm happy just editing sd and hd material using the 720 template and then changing it just prior to rendering. Thanks for everyone's input.

4eyes wrote on 8/17/2007, 12:55 PM
The machine I used was a 2.8Ghz_HT 800fsb w/1gig with an AGP video card, so your computer is faster. My screens are setup at 1280x1024_32bit. I wonder if making changes under "Options | Preferences" for Preview_Device selection would make any difference, maybe worth a try. Mine is setup to use the 2nd display.