[MPlayer-dev-eng] Audio Visualization Plugin

[Gustavo Sverzut Barbieri]

 --- Anders Johansson <ajh at atcrc.com> escreveu: 
> Hi Gustavo,
> 
> The current audio plugin layer will soon be replaced by a new more
> generic one. Attached to this mail is the current work in progress. 
> Warning the attached files "mplayer.c" and "Makefile" brakes mplayer
> a
> little bit so take appropriate precautions before you use them.
> 
> As for where to start:
> 
> If you want to do something that works for real (which imho you
> should) then you could use Welch periodogram method to do the
> spectral estimation. This will give you a good spectral estimates
> where the level of each frequency bin represents the actual energy
> level in that frequency band. 
>
 
> To do the required FFT you could use the fftw package (very fast).
> 
> If you have access to Matlab (and understands matlab code) you could
> have a look at the source code for the psd() function to get the
> implementation started (search for psd.m in the matlab installation
> directory to find it). I guess you can find something similar in
> Octave. I can also recommend the following two books on the subject:
> 
> "Digital spectral analysis with application", S.Lawrence Marple, Jr
> "Statistical Digital Signal Processing and Modeling", Monson H. Hayes
> 

I'll try to find them here in my university.


> I have some sample code for using fftw if you want it (can't send it
> public so contact me outside list).
> 

Please, send me: gsbarbieri at yahoo.com.br


> To check your results try dumping the estimates to file and read them
> with gnuplot or matlab.
> 
> I will be happy to help you with the audio part of the work.
> 
> Good luck,
> //Anders

I'll start looking the Welch Method, then I'll try to implement it. If
I succeed, I'll try to integrate with your new libaf

Thanks for your help! :)

Gustavo

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