[Coladam] More about tone channels attenuation (volume) -and- digital sounds (PART 3)

Daniel Bienvenu newcoleco at yahoo.fr
Fri Dec 11 04:27:47 CET 2009


Thanks for your idea about compression used in modems. If I remember well, it's a kind of dictionnary compression, no?


Back to the current experimentation, I did implement the lossy compression and the result is less noisy than I expected first... of course, it's not perfect, but I've got almost the same result for less number of bits.

http://www.ccjvq.com/newcoleco/sndtest2.mp3

Note : I did optimize a little bit the decoder part to run more quicker. Don't be surprised to hear the difference of speed between this file and the previous one.

So, I've now nibbles instead of 6-bit values. I didn't put yet two nibbles per byte. I've notice a lot of repetitions in the data; using RLE compression should be appropriate and fast enough for this.

If RLE compression works fine, I'll conclude the experiment by releasing my more advance source codes of this coder and decoder (codec). Almost there...

Have a nice day!

Daniel


      


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