Hi!
I'm trying to make a codec in order to stream audio over the internet.
I'm interested in transform the raw PCM data into DCT coefficients and then make some processing.
The problem is that I can't find any Java DCT and IDCT code for audio.
Someone knows something about this topic?
Thanks in advance, every suggestion will be welcome.
This DCT / IDCT works on an 8 by 8 array.
http://forum.java.sun.com/thread.jspa?threadID=482368&start=15&tstart=0
It was specifically optimated for JPEG files. Try searching Java2D forum for DCT. However, your question is about audio, so I don't know how much this will help you.
Thanks, but I need a 1D DCT, and also a bit larger than 64 positions.
But finally I found something, in the FFTPACK page they have
something written in Java http://www.netlib.org/fftpack/jfftpack.tgz
I also found a lot of C code which is easy to transform to Java. One
interesting code is this one http://www.ac.usc.es/arquivos/articulos/1990/gac1990-j09.ps.gz
But finally I'm using a 1D DCT based on a FFT radix-2, it's quite fast.
Kostadin Dabov is the author and he kinldy sent me the code.
Here you can see an applet with his DCT http://www.cs.tut.fi/~dabov/dct/index.html