VMD-L Mailing List

From: Marc Baaden (baaden_at_smplinux.de)
Date: Tue Dec 09 2003 - 10:54:28 CST

Hi Ioana, John and vmd-l,

I remember having had a similar problem at some point. There is another
solution, which is to post-process the video file.

It was a while ago, but as far as I can remember I used a tool called
ffmpeg or another one called transcode to do that.

In my notes I found the following lines:

# error
transcode -i bfactor.mpg -o test -f 1 -y mpeg,null
transcode -i bfactor.mpg -o test -f 1,9 -y mpeg,null
transcode -i bfactor.mpg -o test -f 1 -y mpeg,null --export_frc 9
transcode -i bfactor.mpg -o test -f 0,9 -y mpeg,null
transcode -i bfactor.mpg -o test -y mpeg,null --export_frc 9
# ok
transcode -i bfactor.mpg -o test -f 1 -y mov,null

without any warranty, but one of those should slow the movie down,
I think. At least I remember that I did manage in the end.

Hope this helps,
Marc

>>> John Stone said:
>> Ioana,
>> Unfortunately, most of the video codecs that work with the
>> vmdmovie plugin only support one or two frame rates. This means
>> that in order to achieve the playback rate you desire, you'll need
>> to replicate frames in your trajectory such that each frame is copied
>> N times, where N is the integer factor "slower" that you want your
>> movie to play. MPEG only has three common frame rates, 24fps, 25fps,
>> and 30fps (and the drop-frame equivalents), and the 'ppmtompeg' encoder
>> used by the vmdmovie plugin only does one frame rate in the older versions,
>> so thus far there hasn't been much latitude in allowing other frame rates.
>> I do plan to work on improving the vmdmovie plugin so that some of these
>> things can be done automatically, but at the present moment, the easiest
>> way for you to get the desired frame rate will be to replicate your frames.
>> Let me know if you need more help with this. 

-- 
 Dr. Marc Baaden  - Institut de Biologie Physico-Chimique, Paris
 mailto:baaden_at_smplinux.de      -      http://www.marc-baaden.de
 FAX: +49 697912 39550  -  Tel: +33 15841 5176 ou +33 609 843217