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Re: Spectrogram to a movie file?

Subject: Re: Spectrogram to a movie file?
From: "stoatwizard" stoatwizard
Date: Tue Apr 24, 2007 2:25 pm ((PDT))
> And maybe turning the spectrogram specimens into movies is not
> common.    ??

I saw that technique on the Cornell/macaulay library site
http://www.birds.cornell.edu/brp  It seems to have gone unbeliveably
commercial since I visited a few months ago, but I did eventually
find a link to something like what I saw this idea on -

http://www.animalbehaviorarchive.org/loginPublic.do

I wasn't prepared to d/l the raven plugin which was how they
synchronize their sound and vision which probably saves a lot of
bandwidth. My greenie is 650kB for 4 seconds which is pretty
outrageous - that compression ratio improves a lot as the sound gets
longer since your video is always the same number of frames as you
have pixels across the PNG.

But I liked the idea - it made me revisit Raven in the hope that
would do this for me. No such luck, so I developed that way of
creating these movies using mostly open source stuff.

Avisynth and virtualdub are free (Quicktime isn't, but the technique
can also be used to create WMV which is) You create a PNG of your
spectrogram and use avisynth to dub the audio onto it create a low
framerate ( =3D png active width/ audio duration) movie. Then use the
screencap codec.

Avisynth automates most of that but the learning curve for it is near-
vertical. You're welcome to the script if you fancy a go.





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