Artifact at the interface with a speed jump

[dryfang]

Hello!

I've been using Corel Video Studio for many years. And I am experiencing an artifact at the interface with a speed jump (e.g. from 100% to 800%) ever since as shown in the following examples: In order to shorten the time of a long sequence, an interval with a higher speed (200%, 400% or 800%) was cut out in the middle. However, the exported mp4 files contain an increasing artifact that the picture jumps backwards first before speeding up:
http://yfang.com/tmp/2x.mp4
http://yfang.com/tmp/4x.mp4
http://yfang.com/tmp/8x.mp4
This also happens in VS 2019 and VS 2020 last.

I’ve asked Corel support for help. But the solutions suggested by resetting the system and activating the smart proxy couldn’t solve the problem at all.

As far as I know Davinci Videoeditor offers a filter setting for such an interface in order to smooth it.

Does anyone know a special transition or a work-around which can eliminate or reduce this artifact?

Best regards,
Yang

[lata]

Hi
Certainly there does appear to be an issue where one frame goes back then plays forwards to cause the jump
There are several options to change playback speed, Speed Timelapse, Time Remapping and Variable Speed, all do a similar job.

Speed Timelapse
I tried to apply the speed increase, for me the program added a duplicate frame which caused a small blip but did not go back to the previous frame.
I rendered with and without Smart Render, did not appear to make a difference, but can you try without SR

Time Remapping
Did not work for me?

Variable Speed
Was easier to understand and working with KeyFrames seemed a better option
It appeared to give better results with the limited tests I did.
How does things go for you using Variable Speed

[dryfang]

Thank you for the quick response!
I do have tried with Variable Speed: I set Variable Speed from 100% to 1000% for the first short interval and then applied the high speed of 1000% durch out the second long interval (that actually shortens the time). But there's still an artifact between the first interval (ending with 1000%) and the second interval (beginning with1000%).

[lata]

Hi
I was able to see the duplicate clips when nudging through the timelines, press F for forward, one frame at a time and D for back
But then I did not get the frame going back to play again, I just saw a duplicate.
I was using your samples to set the speed but only have 5 seconds to play with.
The blip only seemed to be when increasing speed, where you reduced speed seemed to work ok, what do you think?

I did manage to cut out the frame that caused the blip
I have attached a VSP showing that, you will have to relink to 2x.mp4

2xmp4.zip

opens using 2020

(1.4 KiB) Downloaded 60 times