Hi Paul, Eric Pettersen, another Chimera developer, I believe tested some different POV-ray settings, and Greg Couch has worked on that code a lot. I don't really know anything about the POV-ray settings because I think I get better results without POV-ray as discussed by Elaine in a previous mailing list message. http://www.cgl.ucsf.edu/pipermail/chimera-users/2009-June/004030.html I'm sending your POV-ray settings question to the mailing list and perhaps Eric or Greg will have suggestions. Tom

Thanks Tom,

The mpeg4 movie with qscale 1 looks pretty good. I forgot to mention in my first message that I was setting bitrate to 10000, and yet still the results were fuzzy around the edges. Seems like variable bitrate is the way to go.

Can you give me any advice on antialias method, depth, threshold (currently I’m using recursive, 3, 0.3, respectively) or jitter (I’m using true with an amount of 1.0). I’ve read the chimera manual entries on the topics but I’m still confused, can’t see much difference when I change variables one at a time. Do you have favorite settings for these variables? Time to process, as long as it stays within a week for a 1600 frame movie is fine, the product will go out as supplemental material for a paper, so I’m willing to wait if some change to the settings I’m using now will make a difference.

Thanks a lot for your help!

Paul

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*From:* Tom Goddard [mailto:goddard@cgl.ucsf.edu] *Sent:* Wednesday, April 21, 2010 11:45 AM *To:* Paul Brandt *Cc:* chimera-users@cgl.ucsf.edu *Subject:* Re: [Chimera-users] POV-Ray setting for movie making

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.

http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/movie.html

Tom

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