What goes on behind the scenes with different render quality settings?

HPV wrote on 11/17/2001, 8:37 PM

Well after many hours of testing, I'm sold on the fact that preview render quality looks the same as good for 95% of the things you can do in Vegas. This is for rendering out to DV. I know for a fact that preview quality doesn't do frame resampling. But my limited slow-motion test look better at preveiw quality than good quality with resampling set. And it's realtime to boot. Yep, realtime.
With something like the deform filter, I can see just a little cleaner edges with the good setting. Also a little better detail on the squashed area of the picture.
Most everything else looks the same, and renders up to 6 times faster.
So just what is going on behind the scenes with the different quality settings? Not worried about Draft.
For anyone that wants to check this out themselves, all you need to do is use the OHCI external monitor feature with recompression activated. Anything that would render will be using the DV codec, as the preview window will say. Now you just need to bounce between preview and good and watch you monitor.
Things you find that look better with the good setting can be region rendered, then just print-to-tape at preview quality (Vegas 3 only).

Craig H.

Comments

db wrote on 11/18/2001, 12:33 PM

i was under impression that the draft, preview, good , BEST was just for the "preview window" quality does NOT affect the PRINT from timeline as to print from timeline VV 3 must do a little pre-rendeing ??

perhaps SF can set us stright on the print from timeline - does the draft, preview, good, best have any affect on PRINT from timeline ??

HPV wrote on 11/18/2001, 12:52 PM

i was under impression that the draft, preview, good , BEST was just for the "preview window" quality does NOT affect the PRINT from timeline as to print from timeline VV 3 must do a little pre-rendeing ??
-------------------------------------
Yes, adjusting them at the preview screen level is only for the preview window. That's part of how I did my testing. But you get the same options when you do any type of rendering. Look under the custom option in the render windows. Change "Video rendering quality" from Best to Preview, name the template something like "NTSC DV Preview", then save it.
Prerender, Render As and Print to DV Tape all have this option.
I really think SF sound rename them something like:
Draft
Good
Good + Resample
Best
I'm looking forward to hearing from SF about this.
The speed difference is hugh.

Craig H.

SonyEPM wrote on 11/18/2001, 8:07 PM

1) Preview settings have nothing to do with rensder settings

2) "Resample all video..." render switch or "Best" render setting (which does ultra high quality re-scaling) are in most cases not needed, but they are there if you need them.

3) "Resample all video..." switch or "Best" render setting can dramatically increase render time- that's why we default to "Good"

HPV wrote on 11/18/2001, 9:46 PM

Thanks SonicEMP.
But for some reason I just can't get you or others to grasp what I'm talking about. I guess I try to share to much info in my questions and everything goes downhill from there. I'm learning. : )

What is the difference between the render quality settings of GOOD vs. PREVIEW ?

rgwarren wrote on 11/19/2001, 8:34 AM

Can someone answer this question for Craig? We would all love to have the definitive answer. I know Craig would.

My guess it that the difference is similar to what I see in Adobe After Effects. Do you want pixel accurate calculations or sub-pixel accuracy on your effects when they are rendered? Looking at the times and "slight" differences in quality for the majority of the effects I think it really deals with some of the more esoteric effects and isn't worth the time for most projects (especially web video!).

I've seen this discussion ad nauseum in a couple of forums and the bottom line is "Does it look good enough?" If not, use BEST.

Let's move on to the cool parts of VV3. Leave the rendering issues to the programmers.

SonyEPM wrote on 11/19/2001, 9:23 AM

There is no bug involved. We'll put together a in-depth explanation of this after Thanksgiving. Right now we're finishing up Vegas 3 and getting that baby ready to ship!

db wrote on 11/19/2001, 10:33 AM

i knew the good, best etc. affected mpeg and codec's BUT i thought DV was DV ! it's quality a STANDARD when using a dv codec - the only way the quality changes was dependent on how good the dv codec it used ! what you get going IN is what you get going OUT and that any rendering would be at DV quality and choosing good - best made no difference when using the dv template ?? ..... well i used the VV 3 default dv template - i've gone out 5 generations and have found no difference between original and 5th generation ! so whatever it is using ( good) i have NO complaints but am looking foward to SF detailed explanation after release of VV 3

HPV wrote on 11/19/2001, 10:51 AM

We'll put together a in-depth explanation of this after Thanksgiving. Right now we're finishing up Vegas 3 and getting that baby ready to ship
---------------------
Very cool, thanks SonicEMP.
With the new timline playback (awesome), I'll use selective pre-rendering at the good setting on regions where it is needed and preview for everything else. Vegas rendering slow compared to every other NLE is now fixed with this approach. Deform is the only effect I can see a difference between preview and good. Haven't found anything the improves with the best setting. I'm sure there is stuff like MPEG encoding and such that might see some improvement, but for DV I'm all good.

Cheers,
Craig H.

SonyEPM wrote on 11/19/2001, 11:16 AM

For no-recompress, as in cuts-only, there is zero difference. Best uses ultra-high quality rescaling calculations, which are hardly ever needed, and there is a big jump in render times.

Good will be fine 99.5 percent of the time-

HPV wrote on 11/19/2001, 3:14 PM

Best uses ultra-high quality rescaling calculations, which are hardly ever needed, and there is a big jump in render times.

Good will be fine 99.5 percent of the time-
-------------------------------------
On my system, the big jump is between preview and good. Best is not much slower than Good.

Good is very slow compared to other NLE software. Once again, I find preview is the same quality as good for 95% of what you can do in Vegas.
Not trying to drag this out, just keep everybody on track for my original question and findings.

Craig H.

rgwarren wrote on 11/19/2001, 3:48 PM

Wow! If rendering speed is that important you might want to consider a hardware solution.

Granted, the software you would have to use would really suck compared to VV but the rendering time would be almost instantaneous. There are always tradeoffs. The flexibility and creativity that Vegas give me is worth the rendering time (most of the time!)

If I need to crank out a real long video project that I know won't meet a deadline by using VV I end up using a hardware assisted editing solution. Those are the projects where you really miss Vegas. Nothing like having to do 8 steps to do something where it only takes 1 in Vegas to make you homesick for Vegas.

What we need is a way to queue up a buch of Vegas projects and let them render all night. Then it wouldn't be a problem.

Cheesehole wrote on 11/20/2001, 1:19 AM

YES YES YES!!!!!!!!!!

batch render regions/projects. that would be SO useful. lord of all things holy and good that would kick a bottomless bucket of a$$!!!

- ben (cheesehole)