Dear friends!

I have implemented a so-called PQMF (pseudo quadrature mirror filter).
Actually, the one which is used in MPEG Audio codecs. It separates 32 input
audio samples into 32 subband samples, critically sampled. So in terms of
Csound we input 32 a-rate samples and output 32 channels of k-signals (ksmps
should be 32).

I suggest someone would like to try PQMF one day. Plus, if I lucky maybe
I'll make MPEG Audio codec model working in Csound for some DSP-related
courses (why not to use Csound instead of say Matlab?)

Actually, I ask you to review my code. I don't like how it looks now. Maybe
it could be optimized a little bit.
Second, any suggestion on how it may go? Like an UDO? or an opcode? It looks
like it should have 32 outputs of k-rate. Is it possible? I know it is
allowed to have up to 256 outs, but maybe it is not rational. 
In MPEG codecs all those 32 subbands go into quantizer controlled by
psycho-acoustical model. So maybe there is no need to separate them.
Otherwise, someone may need to do some special subband processing, not
related to any codecs...

test_mpeg.csd
  
MPEG_PQMF_1.txt
  

Thanks for any suggestions/advises. 



-----
Gleb Rogozinsky, PhD
Associated Professor
Interactive Arts Department
Saint-Petersburg University of Film and Television

Deputy Director of Medialab
Saint-Petersburg University of Telecommunications
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