VirtualDubMod (simple?) question about speeding up a portion of a video

[kaosguy]

I have a high speed video camera (Edgertronic).I produced a nice video clip: http://www.youtube.com/watch?v=OL8xwX0QUCA
Now I want to speed up part of the video, and keep the rest at the current speed.
So I've installed VirtualDubMod and separated the two pieces...


a=avisource("untitled.avi").trim(1,124)# comment
#assumefps(100)
b=avisource("untitled.avi").trim(125,1196)# comment
video=a+b
video


The above works fine, but of course it doesn't DO anything, other than separate the two pieces and then play them back as one..
What code would I have to add (keep it simple, please) to speed up the first part.
Say, by a factor of 6.
I know there is assumefps, changefps, but I can't seem to get the syntax right.
I am not fussy about getting this perfect the first time.
I could select every 6th frame, or blend frames, whatever.


Would appreciate it if someone could suggest exact changes to the above, so I have a starting point for experimentation.


Thanks a lot.


Alan Wolf

[jagabo]

a=avisource("untitled.avi").trim(1,124)# comment
a=a.SelectEvery(6).AssumeFPS(a.framerate)
b=avisource("untitled.avi").trim(125,1196)# comment
video=a+b
video

[racer-x]

I don't use VirtualdubMod, but I assume it's using something like Avisynth scripts. So if you are using 30 fps source and want to speed up the first part by 6x, then you may want to use something like this:

a=avisource("untitled.avi").trim(1,124).assumefps( 180).changeFPS(30)
b=avisource("untitled.avi").assumeFPS(30).trim(125 ,1196)# comment
video=a+b
video

[kaosguy]

Thanks! Worked great!(Both of them.)