VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Mon Apr 08 2002 - 22:23:01 CDT

Dear VMD-L,
  I've fixed a few of the problems that people were having
with the 0.2 version of the vmdmovie script. In addition to
various bug fixes the new version has added several new features.

The new script is available from its page in the VMD script library:
  http://www.ks.uiuc.edu/Research/vmd/script_library/scripts/vmdmovie/

Noteworthy features and other improvements:
  - image smoothing (pre-compression blur convolution)

  - half-size image rescaling (will be arbitrary scaling in future rev)

  - text titling/labelling (NOTE: only works on Unix with NetPBM presently)

  - We are now getting good results with the NetPBM "ppmtompeg" tool
    for looping animations. This would be my first-choice recommendation
    for Unix users. A minor change to the encoder options now forces
    the ppmtompeg encoder to emit all encoded frames, which is an absolute
    necessity for looping animations.

  - The script was fixed so it works with the SGI 'dmconvert'
    tools again. We're still seeing the SGI video encoders drop
    frames at the end of the video for some reason so there's more work
    to be done here.

Remaining bugs and limitations:
  - The video encoder frame rate controls are still quite limited.
    I intend to implement encoder-specific options which will allow
    the user to tune their video output much more than is possible
    presently. Some video encoders (such as ppmtompeg) only support a
    single frame rate, so in order to provide for low-frame-rate
    trajectory animations, I'll have a "frame duplication" mode to do
    three-two-ing, and other similar tricks to adjust frame rates.

  - The windows version still lacks support for the NetPBM-based features
    we've implemented on the Unix side. I'm currently investigating how
    best to handle this, we may provide a pre-compiled NetPBM package to
    make this easier to deal with, but that's a ways off yet.

  - I'd like to eliminate as many dependencies on external software
    as possible, so that users don't have to install or compile numerous
    other packages to do animations. At present we've got it down to
    the following list:
      - NetPBM (scaling, text labelling, smoothing, MPEG-1 compression)
      - ImageMagick (animated GIF production)
      - VideoMach (all compression functions on the windows versions)

Suggestions and feature requests for the vmdmovie script are welcome.
I'll try to work in new features as I have time among the other VMD
development activities we have in progress. As always, please let us
know when you find bugs. Despite the fact that this is only a script,
it has already grown to about 1600 lines of Tcl code, so bug reports are
appreciated.

Thanks, and enjoy!
  John Stone
  vmd_at_ks.uiuc.edu

 --
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
Email: johns_at_ks.uiuc.edu Phone: 217-244-3349
  WWW: http://www.ks.uiuc.edu/~johns/ Fax: 217-244-6078