I know the "ghosting" that he is talking about, its almost like instead of a continual forward motion its like Vegas renders the avi to be 2 step forwards, 1 step back. It has annoyed the hell out of me for a while. But I never noticed that it only seems to happen on DV avi's, I just slowed something down as slow as possible and rendered it out to a 9mb/s WMV and the chosting apears to be gone. it looks much smoother.


I use slow motion enough that I will consider rendering out to WMV first and then back to DV to get rid of the ghosting.

Depending on what you want to see wth Slo-Mo, I sometimes turn off the Resampling. If you speed up/slow down even the slightest, it usualy turns on, making the ghost effect. If you disable the re-sampling, for slo-mo it will just stretch the length of the frame, and if you speed up it will cut out frames.

There is programs that do exactly what you want, but they cost around $1000. They do a good job from what I understand. Also, if your action if to fast, it will blur the image on your camera (due to shutter speed). If you got a better camera with a faster shutter speed, it would give you crisper frames, and would probely look better slo-mo'd.

Hmm, I never thought of turning off the resampling - I'll give that go right now

As for the camera, we use Sony's DSR 250P with the shutter speed set to 100. I'm thinking of changing it to around the 250 mark (the same speed I use for still photography for this type of image) for a slightly crisper image, although I've found speeds above 1000 look too artificial for my liking

Here's another app you might want to consider. It's by DynaPel, the folks who created Steady Hand. This one is called "MotionPerfect." It does both slow and fast motion.

They also have one called "Slow Motion." However, the MP appears to have more control than does SM. There is a comparison chart of the two apps on the site which are good to refer to.

http://www.dynapel.com/com/private/mp_overview.htm

I've never tried it. It may do no better or worse than Vegas. The few times I've used slo-mo in Vegas, it has served my purpose. However, I must say the demo video (auto slidiing off track) on the above site is impressive.

J---

Two comments.

First, turning off resample will stop Vegas from blending adjacent frames in order to synthesize the intermediate frames. This eliminates ghosting and also makes the video much sharper. The downside is that the motion becomes jerkier.

Second, I have used MotionPerfect. It is one of the few slow motion applications that actually attempts to truly synthesize the intermediate, extra frames required to get slow motion. It does this, as near as I can tell, by using some of the same algorithms that are used in MPEG encoding, namely motion estimation. It actually looks at groups of pixels and estimates where they will be in the next frame. In MPEG encoding, this information is used to create the difference information needed to create the next frame without having to store the entire frame. For MotionPerfect, it is used to actually create a frame that never existed.

The results can, at times, be unbelievable. There is an eery fluidity to the results. Absolutely pure, smooth, motion. However, you can get some really wierd, unwanted artifacts. For instance, I used it on a scene where I was panning past a picket fence. All the pickets melted and warped on the intermediate frames.

There are some $1,000 and up applications that also do this, and they may work more predictably. There was one I briefly considered, but they didn't have anyway to evaluate it prior to purchase. The high end programs let you go to problem frames and give the program some manual assist to help it avoid creating artifacts.

I also got involved in two unusual uses for this program. The first was to use it to create the pulldown from film to video. I had individual frame captures from each frame of film using the Workprinter. The film was shot at 18fp. I then used MotionPerfect to create the extra frames so that the motion was the proper speed when shown at 29.97 fps. For those scene where the artifacts didn't appear, the results were absolutely other-worldly. They were neither film nor video, but something entirely new. It had the warmth and depth of film, but a fluidity far beyond either medium (because the source was, in essence progressive, there were no interlacing artifacts). If this could be made to work reliably, one could create a whole new look and feel.

The other application was created by someone whom I introduced to MotionPerfect. He was (and is) involved in stop motion animation. You know, take a single frame, move the clay model, take another frame, move the model, etc. (Wallace & Gromit, Chicken Run, etc.). Really tedious stuff. He was looking for a way to let him take far fewer pictures and then have the software create intelligent "tweens." Again, MotionPerfect worked in some cases, but not others.

Bottom line: Worth a look.

Sure you aren't seeing field artifacts?

Sure you aren't seeing field artifacts?

These were BIG artifacts. Looked like the wicked witch of the east melting. I also had another sequence where someone was running and if you went frame by frame, it looked like their foot had been broken, then magically healed itself in the next frame.

Thanks for the replies everyone

The solution in the end was that Vegas' slo-mo is about the best at this level, although I am convinced that a slightly faster shutter speed on the camera will also lessen the effect, too

I am convinced that a slightly faster shutter speed on the camera will also lessen the effect, too

Let me know if you do any experiments on this. I just shot some more volleyball yesterday, but this time used a high speed shutter setting. I'll be experimenting to see if the results are any better, but I'd be interested in anyone else's results.

Veggie: Any chance you can park a few seconds of this footage (unrendered) on an ftp site someplace?

The standard .avi file that I'm slowing down? If so, yes - but I'll need a direct E-mail address for you so that I can tell you where it is

John Meyer:
Let me know if you do any experiments on this.

I've had a quick experiment with it, but it was just a quick one. 1/100 sec is definitely better than the standard 1/50. I then tried 1/215 and 1/3500 but the results offered nothing as the jumpt between the two speeds was far too much

When I next get a chance I'll be comparing 1/100 and 1/215 as I'm convinced the answer (and most natural looking footage - obviously you need some motion blur in the background otherwise there's no sensation of speed) lies somewhere between these two speeds

So if I am doing alot of stretching of clips in the timeline, i should either have "force resample" on- or have resample off?

I have been Stretching rather than using velocity envelopes. Does VV do something different when Stretching than when using velocity envelopes?

Good question. The answer is yes.

Try this experiment. Take an event that's exactly 10 seconds long. Make a copy of it so its on two tracks aligned vertically, no audio.

Stretch the first track to exactly 20 seconds in effect doubling its length.

On the second track add a Velocity Envelope and set it to 50%. Do not stretch.

While both track have nearly the same slow motion effect the track with the Velocity Envelope has roughly 300 frames so while you have slow motion, then event's time span is still just 10 seconds. Now look at the track that you stretched. Its time span has doubled to 20 seconds, yet the slow motion effect is the same which you can confirm if you carefully pull down the opacity level on the top stretched track and stop play you'll see they are at the same place. Pretty cool!

Which method you use depends on the effect you want to get. If you have some audio tied to the event streching it will of course mess up the audio. So in that case you would want to use an Velocity Envelope.
If however you're adding/altering the audio you may want to just stretch which also adds time. The advange is your doubling the frames which will give you smooth slow motion playback. When you use an envelope obviously the process is handled differently.

So if one is having problems with jittery results using velocity envelopes and wants to slo-mo a clip, say, half way into it, maybe it would be better to split the clip at that point and stretch it....interesting, I'll try it.
Thanks BB,
Randy

So if I am doing alot of stretching of clips in the timeline, i should either have "force resample" on- or have resample off?

If you stretch (i.e., create slow motion) in Vegas 4.0, it resamples the video and creates intermediate frames by blending adjacent frames. This gives smoother motion, but the new, blended frames are not as sharp as the real frames because they are a blend (like a crossfade) of two different frames. So, if you turn off resample, you will get much sharper video, but the motion will be jerky.

Try this test yourself: Find a fast motion clip. Render ten seconds using smart resample and then render the same ten seconds with resample turned off. Watch the results on your TV monitor. The difference is not subtle at all.

I recently posted the results of testing I did in order to get the best possible results from volleyball video (really fast motion). You can read the results here:

Slow Motion Settings

Thanks John,
I just happen to be doing a local high school volleyball highlights video...I'm anxious to try your settings. BTW, what kind of camera do you use and what shutter speed do you use for V ball?
Thanks again,
Randy

BTW, what kind of camera do you use and what shutter speed do you use for V ball?

I'm still using my original DV camcorder, a Sony TRV-11. I've been contemplating the VX2000 or TRV-950, but they're a lot of money, and most of my video work (weddings, school productions, ballet, and video restoration), I do for free (I am semi-retired).

I've just been using the default shutter speed, because there isn't that much light in most gyms (compared to outdoor lighting). The TRV-11 doesn't give you direct control of shutter speed, but you can change it by using one of the special effect presets (like Spotlight mode). According to information I obtained three years ago, these are the shutter speeds that you get with these various modes (on a Sony TRV-11 NTSC -- other Sony models may, or may not, be the same):

Soft portrait mode: 1/500 sec.
Sports lesson mode: 1/1500 sec.
Beach & Ski mode: 1/250 sec
Low lux mode: 1/8 sec.

With image stabilization on, the shutter speed is 1/100; with it off, it drops to 1/60 sec.

I have the opposite problem - I have to speed up the video (I sent some 8mm film out to be transferred to miniDV tape, but did a crude video capture from the projector myself and had narration done off of that while the film was being transferred. The transferred tape runs 90 min instead of the 60 min capture I did (I must have goosed the projector speed too much trying to cut down on the flicker) so I figure I wil have to render it to avi speeded up some (I can't just cut the narrative apart and spread it out). I was going to use the velocity envelope - is that the best way?

Thanks