agf_030fpu

Short:        AGF - n*8-bit Sample Pre-Packing Processor w/src
Author:       olethros@geocities.com (Christos Dimitrakakis)
Uploader:     olethros geocities com (Christos Dimitrakakis)
Type:         util/pack
Replaces:     util/pack/agf.lha
Requires:     68030+fpu
Architecture: m68k-amigaos

OVERVIEW

AGF is a sample pre-processor. It transofrms the data into a form having very
little information content. This makes it easier for compression programs to
pack it down to a small size. AGF combined with GZIP gives an average
compression of 50% and it is always better than any other compression method on
its own. It is similar to ADPCM, but better :)

HISTORY

05-09-1999 : Released a version that works properly (more or less)

SUMMARY

AGF - Adaptive Gradient-descent FIR filter.

This is a neural-network-like adaptive FIR filter. The adaptation is
deterministic, which means that the sample can be recovered from the processed
file without needing to save an FIR coefficients to it as well. Adaptation is
done on-line, on a sample-by-sample basis.

USAGE

AGF MODE sample processed_sample

The processed sample can then be efficiently packed with any kind of packer.
I recommend xpk (xGZIP or xSQSH). lha/lzx will also do :)
The results are always MUCH better.

Modes:
   x  :  extract (decode) using a linear ANN
   c  :  compress (encode) using a linear ANN
   xd :  extract (decode) using a static filter
   cd :  compress (encode) using a static filter

TODO

Make an xpksublib out of it.
Add options for adjusting the number of coefficients and adaptation rate.



BUGS

Might have problems with samples that clip a lot..

Bugs Reports to olethros@geocities.com with "AGF BUG" as the subject message please

SEE ALSO

see also dev/basic/gasp.lha for a similar pre-processor where the adaptive
process is controlled by a Genetic Algorithm