libdolbyb treats audio recordings to apply or remove something similar
to what Dolby B noise reduction codecs in high-end tape recorders do
by emulating in software the electronics of a real Dolby B unit.
It translates dolbybcsoftwaredecode.sf.net from Pascal into C giving
a generic C library and a command-line tool and is used as a new SoX effect
in sox_ng-14.6.0 on - poke sox_ng above and sox_ng and Releases there.
| LibI64 | ||
| m4 | ||
| test | ||
| .gitignore | ||
| Calibrate.c | ||
| Calibrate.h | ||
| ChangeLog | ||
| configure.ac | ||
| COPYING | ||
| DCfilter.c | ||
| DCfilter.h | ||
| DiodeClip.c | ||
| DiodeClip.h | ||
| dolbyb.1 | ||
| dolbyb.c | ||
| dolbyb.h | ||
| DolbyBi64.PP | ||
| FindOutSmp.c | ||
| FindOutSmp.h | ||
| HPF1.c | ||
| HPF1.h | ||
| HPF2.c | ||
| HPF2.h | ||
| HPF2SetVals.c | ||
| HPF2SetVals.h | ||
| HPFAdj.c | ||
| HPFAdj.h | ||
| INSTALL | ||
| libdolbyb.3 | ||
| libdolbyb.c | ||
| LPFAdj.c | ||
| LPFAdj.h | ||
| Makefile.am | ||
| Mixers.h | ||
| Param.c | ||
| Param.h | ||
| README | ||
| SetGate.c | ||
| SetGate.h | ||
| SidePath.c | ||
| SidePath.h | ||
The libdolbyb project aims to translate dolbybcsoftwaredecode.sf.net into C so that it can be used as a library in SoX_ng. If it's useful to other open source programs, that is very welcome. The C version produces exactly the same audio output as the original Pascal version compiled on a 32-bit system; the audio output of the Pascal version compiled on a 64-bit system differs in a handful of places by one bit value from what you get compiling it on a 32-bit system, presumably some problem with FreePascal, but the differences are sure to be well below any noise floor or the program's deviation from the ideal Dolby B response curves. There is a mailing list libdolbyb@groups.io for discussion and for announcements of new versions. To subscribe, go to http://groups.io/g/libdolbyb or send an email to libdolbyb+subscribe@groups.io The original source code has no copyright statement or licence which makes it in the public domain. The C version of the library is covered by the GNU Public Licence version 2. Yes, GPL, not LGPL. If you want to include it in a commercial product, you can either translate the original Pascal sources and make them work or use FreePascal to compile the original library and link to it. The name "dolbyb" is pronounced "DOLL bib" and is a new proper noun without any implied reference to Dolby Laboratories Inc. with whom I have had nothing to do except as a longtime user of their excellent products. I have the original author's blessing for this work Martin Guy <martinwguy@gmail.com> March 2025.