View Full Version : choppy playback in slomo

scott w. keller
03-07-2003, 06:38 PM
Been loving my T2, dual Xeon machine, but I just tried something that has me puzzled. I was using TeD and went into edit on a clip that was a pan with a lot of detail. It played smooth in regular time, but I thought it may look better slowed down somewhat. I highlighted the clip clicked edit and set the speed from 100% to 90% and the playback was really choppy. Preferences settings as per recommendation for dual. 2.0 xeons, and have worked fine for everything else I have thrown at it. Drives are testing 125MB/sec. The machine is more than adequate, can't believe I would have to compress capture. Running 3718 build. Someone has to have come across this before, infact I think I read the solution on the old forum, but did not save it.

03-07-2003, 08:29 PM
Slo-mo looks best when it's done at 1/2 or 1/3 speed. Other speeds can make it shaky very easily because it's harder to process frames to the right length.

All of my slo-mo's through the T2 have been great. Unless I run them through Aura for something, then I have to use the Fix Motion filter.

If you still have problems, try rendering it. If the rendered version looks good, then you might have a preference set wrong.

03-07-2003, 10:16 PM
About a year ago, Andrew and his team improved the slo-mo quite a bit.

One thing about slo-mo, certain moves with some scenes just don't translate well for slo-mo.
I've found that even with my deck's dynamic tracking, lot's of movement, especially rapid diagonal moves, will most certainly produce less pleasing results no matter what speed you use.

Think of it in frames. If on one frame the object is several degrees to the right, and the next frame the object is several degrees towards the left, slowing down the playback will result in a jumpy animation look since the object is never in a position in between.

I'll have to play with the deck's slo-mo, Toaster, and my other systems slo-mo to see if there is a noticeable difference. So far I've not noticed one since NewTek improved it.

03-07-2003, 11:03 PM
One of the key things with TEd slo-mo is to stay at 51% of the speed or higher. If you do that, it should look really good.

If you go slower than that, it will drop to single field, with a reduction in quality.

It can still look good, and if you need to you need to, but not as good as at the faster speeds with both fields.

03-08-2003, 06:08 AM
Still, it shouldn't be choppy. I routinely demo the Toaster's ability to stretch clips to weird values (like 42.68) with good-looking slomo, and usually drop it down to 17% or so to really nail the point down. True, it isn't absolutely perfect at such ridiculous speeds, but I wouldn't describe it as choppy ...

03-09-2003, 01:08 AM
Agreed, I wouldn't call it choppy at any of those speeds.

03-09-2003, 10:42 AM
This may or may not help, but I've had choppy playback problems in other situations when my video drives get too full to properly cache information (even the Force Render FX doesn't help). It feels like the cache file gets truncated without an error, and the project will have persistent playback problems until you recache it:

If your video drives (or wherever you're caching, see the preferences item) are close to full, try freeing up some space on that drive, deleting the old cache file (or fileS, sometimes T2 will leave old caches around when it crashes), and reload the project (it should recache at this point, the hard drive light will blink for a while and the green light will be off). When the green light comes back on, try playing that section again and see if it looks any better.

Good luck! -MG