using mencoder to speed up video by skipping frames?

[tomviolin]

I have a very simple task. I have a number of .mpg files that I would
like to convert to .avi using mencoder. This is simple, and I can do
this.

However, in addition what I need to do is have the resultant avi files
only contain every 10th frame of the original mpg, and have the avi
still play back at 30fps, thus playing back the original video at 10
times the speed.

I've tried the -vf framestep=10 option, this seems to do almost what I
want except that the avi plays back at 3 fps, instead of the 30 I want.
I've also tried tacking on a -ofps 30 with no effect, and also adding
filmdint=io:10:1 and it still doesn't do what I want.

Any ideas out there?

Thanks.

[Heiko Recktenwald]

tomviolin wrote:

> I've tried the -vf framestep=10 option, this seems to do almost what I

Great. Is it MPEG 4? Then I would extract the divx with avi2raw and
create a bla.mp4 with mp4creator -rate=30 bla.divx bla.mp4

avi2raw and mp4creator are part of Ciscos MPEG4IP, mpeg4ip.sf.net ,
binaries of the tools for Windows are in the net.

[tomviolin]

I have found a solution to my problem. The key was to use the -speed
option in conjunction with the filmdint option. The filmdint=io=10:1
option outputs 1 frame for every 10 input, and the -speed 10 option
speeds up playback by a factor of 10. These combine to give me what I
want. Here is the complete command line I used:

mencoder -vf hqdn3d=5:4:10,filmdint=io=10:1 -speed 10 \
-ovc lavc -lavcopts vcodec=msmpeg4v2:mbd=2:trell:vbitrate=8000 \
-of avi -o 2004-1202.avi 2004-1202-*.mpg