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Unofficial VirtualDub Support Forums > Newbie Questions > Jitter, Judder, Frame Jumping Issue

Posted by: WhiteKnight Dec 27 2013, 09:55 PM

Hi,

I've been trying to solve this issue for a few days now. In the clip below, there is a noticeable jitter-like symptom where the video does not play smoothly but instead seems to slightly "jump" during motion, almost like a frame is missing or something. This video is encoded at 30fps.

The only way I could get it to play somewhat smoothly was to use the Frame rate - Process every other frame (decimate by 2) option by then the framerate drops to 15fps. I'm not sure why lowering the framerate would make it appear smoother though. I thought the problem would be worse with a lower frame rate.

What is the actual name of this issue I'm experiencing (jitter, judder, frame skip, etc)? And is there a way to fix this without re-encoding with different settings?

Moderator note - links to copyrighted material removed

Thanks for any info you can shed on this issue.

Posted by: meowmeow Dec 27 2013, 11:51 PM

Do you like AviSynth?

CODE

#script supposed to remove duplicate frames by "visual" compare
#download program http://neuron2.net/multidecimate/multidecimate.html
#put multidecimate.dll into avisynth\plugins folder

#first pass
AviSource("file.avi")
ConvertToYUY2()
MultiDecimate(pass=1,quality=3)
ConvertToYV12()

#open .avs with VirtualDub, run video analysis pass, exit (don't view manually)
#mfile.txt created
#run MultiDecimate.exe to create dfile.txt

#second pass
#change to "pass=2" in function MultiDecimate and save .avs
#ready for play or encode

http://i.imgur.com/8T0yV8U.png

Maybe there's better AviSynth scripts than this program idk.

Posted by: WhiteKnight Dec 28 2013, 11:12 PM

Appreciate the reply. Unfortunately it didnt resolve the issue. However, I was able to use the method to see that between certain frames the ratio in mfile.txt file is 6.0+ and this corresponds to the "jumps" that are seen when the video is played. Is there any way to smooth these jumps out or is it now embedded this way in the encode and nothing can be done on the post processing side?

I apologize if this was copyrighted material but I only included like a 30sec clip so I thought it would be ok to post the link.

Thanks!