I haven't used it myself but I contacted a person that uses Dolby A and I Think he has contacted you. I really appreciate what you are doing even though I have not used your software since I do not have any Dolby A encoded material. I do look forward to try out your future compressor you talked about earlier. I also love that you software is available to Linux and hopefully your compressor can be a LV2 or/and VST plugin.
One thing -- I truly do not know what you know or even about what you know, so PLEASE forgive me if this might seem rude... Before 1yr ago, I would have also said that I had no DolbyA encoded material, yet a large number of my music collection WERE DEFINITELY DolbyA encoded... For example, I had my ABBA collection for over 10yrs (really, really, long time), yet knowing what I know now, and listening to it, I kind of 'whack' the side of my own head now realizing that my ABBA collection IS DolbyA encoded. Here is an example of my UNINTENTIONAL DolbyA material collection (likely well over 1/2 of everything I own including): Petula Clark collection of 4 CDs, massive Carpenters collection, a copy of ABBA Gold, 3 Simon&Garfunkel albums, 2 Linda Ronstadt albums, Fleetwood Mac Rumors, Christopher Cross Album, massive Olivia Newton John collection, Herb Alpert Album, Herb Alpert & Brasil66 Album, Burt Bacharach set of two albums, Dionne Warwick Album, Chicago CD, Queen CD, Carly Simon CD, 2 Anne Murray albums, Bangles CD, Bananarama CD, Moody Blues CD, The Cars, Suzanne Vega, Paul McCartney & wings from HDtracks, Carpenters from HDtracks...
My point in listing these -- you (or someone) just might (more likely than not) REALLY have a DolbyA encoded album (not vinyl, but CD or electronic.) This has been a very common thing, because I have almost had to check my sanity when I realized this. I have gone back directly to the CD source and lo&behold a CD that I might have purchased over 5yrs ago or something I downloaded deep in the past has been left DolbyA encoded.
I did NOT carefully select the material that I put on my repository, because I have found that more likely than not that a given piece of material that I have TRULY, REALLY benefits from DolbyA decoding. I honestly cannot claim that every item that seems to be DolbyA encoded really is -- but I have some traceably DolbyA encoded material and it really doesn't sound much different in 'compressed' sound and HF emphasis from the material that I have given as examples.
The only reason why the material can be left DolbyA encoded is that the result isn't really all that fatal (just a bit too much HF empahsis, too much of a compressed sound, and more hiss than there should be on older recordings from older tape formulations and tape machines..)
Some of my collection that tends to sound quite nasty by my estimation turns into audiophlie grade upon decoding -- REALLY!!!
If you don't have anything that is DolbyA encoded, I understand... But if you have a large electronic or CD sourced collection (or a moderate sized one like mine), then there is at least 1/2 of the selections that benefit from DolbyA decoding. I'd estimate that at least 50% -75% of my collection is almost provably DolbyA encoded, and perhaps 10% is questionable either way (might be sidechain compressed because of excess HF loss but no expansion dynamics problems.) The rest of the 15% is NOT DolbyA encoded.
Wrt my compressor (and possibly expander project) -- my compressor project is essentially on hold for two reasons 1) percieved lack of interest, 2) I have learned a hell of a lot on the expander and psuedo-DolbyA project -- need to feed back info into the compressor project.
Wrt my general purpose expander project -- it isn't really 'on hold', but has been in development on an ongoing basis during the psuedo-DolbyA project. Initially, the psuedo-DolbyA was part of the expander project, but I found that the pseudo-DolbyA design requirements to be so very specific, that I seperated out the high level portions of the psuedo-DolbyA. However, the vastly improved anti-intermodulation dynamics techniques that I have used to make the psuedo-DolbyA work so beautifully (clean, clear, no roughness) are being fed back primarily into the expander project and also secondarily the compressor project.
I already had pretty darned good dynamics classes (attack/decay/gain-riding/etc) in C++ for numerous purposes when starting the expander & DolbyA projects -- the compressor was the basis for all of the work. However, given my own sense of perfection, I have been striving for perfection in the DolbyA project -- FURTHER MORE STRONGLY controlling the mathematically unnecessary intermodulation effects -- thereby producing a DolbyA decoder that changes the character of the sound back to before the DolbyA encoding, but without many of the typical artifacts of either SW compression/expansion or real HW compression/expansion. I think that the ONLY intermodulation distortions left over on the psuedo-DolbyA is greatly attenuated and the sidebands are limited to below about 50Hz wide on the LF bands, and 450Hz wide in the midrange bands and 1000Hz wide in the HF bands. Even that those very significant limits (probably 10dB-20dB down at those bandwidths), the technically unneeded modulation products are attenuated even for the nearby sidebands.
Of course, one cannot do gain control without creating sidebands, so I had to leave the sidebands intact so that gain control would happen (yea, I know that there are tricks to move the sideband power over to one side and to make the distortion less noticeable, but that is too much work.) For example, the compressor is built from a 3band compressor, an 8 band compressor, a 1 band last chance compressor, and a carefully crafted set of limiters (lots of stuff.) The expander has 48 degrees of freedom in its gain control, and the vastly simpler pseudo DolbyA needs to meet really specific design criteria.
(BTW -- I am not exaggerating about the 48 degrees of freedom in the expander -- that is why the expander can provide 1:1.6 dB or higher expansion ratio without pumping.)
Oh well, I am really just trying to help, and anyone is willing to email me for access to the psuedo_DolbyA. The SW will work as long as the OS/HW supports the code. I am limiting the time for the offer for my own sanity, however :-).