[Chimera-users] POV-Ray setting for movie making

Tom Goddard goddard at cgl.ucsf.edu
Wed Apr 21 11:45:16 PDT 2010

Hi Paul,

   Sound very likely that the quality degradation is from the movie file 
compression.  The movie compression algorithms use a perfect image every 
tens of frames and differences that are compressed between those frames 
I think.  I suspect MPEG1 is one of the worst because it is the oldest 
format.  You may see some improvement using the MPEG4 based codecs (mp4, 
avi, and mov movie command mformat values).  The movie encode command 
two options that control compression are "bitrate" and "qscale".  The 
bitrate option pertains to fixed bitrate compression schemes while 
qscale refers to variable bit rate (more modern) compression methods.  
In your old Chimera version I believe the default is bitrate 2000 
Kbits/sec which gives pretty horrible quality but was chosen to improve 
the chances of PowerPoint being able to play the movie.  Current Chimera 
daily builds instead use qscale 8 as the default which gives quite good 
quality but much bigger movie file size.  If you really want the best 
possible quality and giant movie files is not a problem use qscale 1.



> Hello,
> I am using chimera alpha version 1.3 (build 2577) running in linux 
> (sled11) to make a movie using POV-Ray.
> The quality of the first few frames is stunning but thereafter becomes 
> fuzzy around the edges of the molecule.  Is there a way to fix this so 
> that the entire movie is as clear and nice as the first few frames?  
> Is there something wrong with my settings?  Is what I'm seeing an 
> artifact of mpeg compression?
> I am using the following POV-Ray settings to make an Mpeg1 movie
> Quality 11
> Antialias: true
> Antialias method: recursive
> Antialias depth: 3
> Antialias threshold: 0.3
> Jitter: True
> Jitter amount: 1.0
> Transparent background: false
> Wait for POV-Ray to finish false
> Keep input files: false
> Thanks for the help!!
> Paul

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