Jerky playback with track motion

LoTN wrote on 1/7/2010, 11:49 PM
Hello all,

Getting jerk and flicker on a very basic "splash screen" project, I tried to understand the root cause using a single track containing text media and track motion. My guess is that it has something to do with the movement speed, so it could also be related to the framerate.

This is the very first time I see this. I did tests with 8c and both 9c versions, the outcome is the same.

Here is the "splash" tentative: http://www.vimeo.com/8317650

Here is the troubleshooting project render: http://www.vimeo.com/8600962

In order to verify my assumption about the fps / motion speed relation, I've put the same media on the track but changed the movement speed. Last segment is 30s and is quite fluid but I can see some flicker too.

Project is 720p 25fps. I tried setting reduce interlace flicker flag, adding a supersampling enveloppe, raising the framerate to 50fps, nothing did really solve the issue. Renders to files are almost identical to what I see using RAM built previews.

A word about the text media: it's a TrueType font, size set to 288, foreground and background set to transparency, shadow effect only.

Is there one guru that could shed some light on this ?

Comments

farss wrote on 1/8/2010, 2:45 AM
Only looked at the first sample. That is really bad motion, so bad I have to risk possibly insulting your intelligence :)

Have you very carefully checked for errant keyframes?
I've just spent a bit of time on an AE project with much the same problemo looking in all manner of places until I finally realised they object that was moving smoothly had a few less keyframea than the one that wasn't. Vegas makes it very easy to create a keyfram where you might not want one. Use the next/previous keyframe buttons to check you haven't got two stacked close together. Also check your keyframe interpolation.

Next thing is Vimeo doesn't do 25fps unless you pay, sometimes their conversion to 24fps mungs things up with motion.

Digging deeper into the technical stuff, the skier has no motion blur, that can make for jerky motion at low fps. Use MB in conjunction with Supersampling to get good looking MB. Set MB to asymetric gaussian in your project for the most natural MB.

Bob.
LoTN wrote on 1/8/2010, 2:53 AM
Hum, my intelligence ? Maybe some bad fluid motion in my brain :D

I confirm there are only two keyframes, only begin and end. What is interesting with the second video is that the more slow is the motion the more it gets smooth. Vimoe reveals my issue, possibly worse than it is on my local fiel renders. I've tried AVC, MPEG, uncompressed it's always the same jerky playback.

I already had a try with MB but it wasn't really helpful. I'll test again with a more longer trial & error process.

thanks Bob.
LoTN wrote on 1/8/2010, 5:13 AM
No luck. It's time to give up on this one...
farss wrote on 1/8/2010, 5:27 AM
Send me the project file and the other bits and I'm pretty certain I can fix it for you very quickly. Email address is in my user profile. You'll need to send me a message first, I'll bounce it back to you and then you can send me ths file(s) as an attachment. Have to wait until tomorrow though.

Bob.
LoTN wrote on 1/8/2010, 6:06 AM
Wow, that's really cool. But don't waste your time on this. It's been weeks I am trying to get it and video is not for my living...

Anyway, many thanks bob.