Supersample affects slo-mo. Yes it does!

johnmeyer wrote on 5/15/2007, 7:16 PM

OK, lots of post over the years about how the supersample envelope on the video bus does not affect video, but instead only acts on media generated by Vegas.

Well, I have now found out that this is not true.

1. Take an m2t HDV file (although my guess is that this will work with regular DV as well).

2. Set the playback rate to 0.25, and put a velocity envelope on the event and set it to 25%. Thus, we are going to play back at 1/16 normal speed.

3. Disable resample for the event.

Now, render to an MPEG-2 file using the normal DVD Architect NTSC (SD) template and view the result (after preparing to a DVD) on a normal TV monitor. In fast motion sequences, you should see "double vision" because both fields are being displayed simultaneously.

Now, add a supersample envelope to the video bus, and set it to "2." Repeat the render as in the previous paragraph.

Note that there is no longer any "double vision"!!

This is actually the effect I was trying to achieve, namely a continuous series of still photos.

Here are the results. The first is without supersample. Notice the "double vision" on the club head at the top of the swing. By contrast, the second version, with supersample set to 2, shows a perfectly clean club head motion. These two files, when encoded to interlaced MPEG-2 and displayed on an NTSC monitor show exactly the same thing as in these YouTube clips.

No Supersample

Supersample set to 2

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Comments

busterkeaton wrote on 5/17/2007, 8:47 AM

How come we don't get to see the downswing?

What a tease!

johnmeyer wrote on 5/17/2007, 2:44 PM

How come we don't get to see the downswing?

Good point! I was in a hurry and rendering the smallest possible segments. The following is the complete swing. Note that the Pacific Grove golf team, of which this person is a member, won the Central Coast Section golf tournament just a few hours after this was taken. That tournament includes all schools between San Francisco and Monterey, CA. Helps to have Pebble Beach as your practice course (local high schools get to play there for free).

I uploaded this clip as a WMV rather than MPEG, following the directions given by another user here on the forum. It will be interesting to see how the quality compares.

Here's the clip (hopefully it will have uploaded by the time you read this):

Cheesehole wrote on 5/17/2007, 3:11 PM

>1. Supersampling only affects slow mo IF Smart Resample is disabled for the event that is slowed. If "forced" or "smart" is selected, then supersample has no effect.

Yup.

>2. As Bob pointed out, the effect of the supersample in this case seems to be to eliminate either the odd or even fields (not sure which). That is hardly a great thing.

Yup also.

>3. Changing the supersample to higher numbers has absolutely no impact, either positive or negative. Nothing happens at 0 or 1; the field disappears at 2; then nothing more beyond that.

>Thus, I think this is an interesting, but not particularly useful, anomaly.

Afraid so.

I went through all this a while back trying to get Vegas to treat 60i footage like 60p in an NTSC project. I happened upon that supersample trick/glitch but ultimately I had to render my stuff out to 60p and then bring it back in to get the results I wanted. (I need to sync two tracks at the field level for a good 3d effect - and also be able to change velocities without losing the field sync)

It makes me wish we had more control over de-interlacing at the clip level so I could avoid that whole render. Vegas just won't let go of the fields no matter what you do.

Oh well it's still easier than working in AfterEffects.

DJPadre wrote on 5/17/2007, 7:01 PM

"It makes me wish we had more control over de-interlacing at the clip level so I could avoid that whole render. Vegas just won't let go of the fields no matter what you do."

try mike crash's Vegafied Smart Deinterlacer
It a VDub plugin which has been written to run in vegas.. works a treat