[snip..] Would anybody be interested in getting this program at all? It's Windows-only at the moment...
tl;dr- some of this gets OT, so for those who aren't in to it, please ignore.
I'll throw out a couple potential alternate use cases which will apply to other tapers generally, and also a oddball concept of mine I've thought about for years.. which I don't expect this program to evolve into, but your development of it has gotten me thinking about it again and I'd love to discuss it more in depth with anyone interested here or elsewhere (happy to take it to another thread, PM or offsite).
Relatively common taper scenario 1-
I've not recorded using a secondary safety track on the same recorder myself, which is the intent of this routine. But I have recorded a safety backup to a secondary recorder at times, as do other tapers. Most of the time that safety recording isn't needed, in the same way that a lower-level safety track made on the same recorder isn't, and when it is most folks will simply discard the primary recording and use that secondary safety recording. However, this program could potentially auto switch between the two, using the primary recording wherever possible. The potential problem with doing that would seem to be achieving a sufficient degree of sync between the two recordings, especially if the back up recorder didn't share the same clock (probably most of the time). Sync that is otherwise audibly "good enough" for mixing AUD and SBD via the typical post process of aligning and stretching may not be close enough for the detector.
Relatively common taper scenario 2-
Plenty of tapers find themselves needing to deal with dropouts, intermittencies, or other brief problems in one channel of a typical 2-channel stereo recording. Most often the solution is a cross-fade to the other channel and back again. That causes the recording to briefly cross-fade to mono and back, which is unfortunate yet is an improvement over doing nothing or simply fading to silence in the damaged channel. This program might automate that process, but may require significantly looser detector settings that are only triggered by the intended obvious problems and not by desirable stereo difference between the two channels.
Oddball scenario 1-
My oddball case is similar to common taper scenario 2 and involves a couple decade of stealth recordings made with a four channel mic rig. That rig started as two complete identical stereo rigs, one assigned to Left/Right and the other to Center/Back, with alignment and sync between the two achieved in post. That evolved to using a single recorder for all four channels (Tascam DR2d) making operation and post processing far simpler. It then further progressed from using two identical preamps to a single 4-channel preamp. But regardless of that evolution, inevitably there were times when one recorder hickuped or failed, or one preamp battery died, or most commonly- one wire or connector went intermittent, crackly, poppy or whatever. I've a significant number of recordings that are compromised in that way. Most of the time the solution is just to not use the bad channel in the mix, or to manually cross fade around the problem from one of the good channels.. This is essentially the same situation as common taper scenario 2, except there are two or three remaining good channels instead of just one to cross-fade from, some a bit more different than others.
Oddball pipe dream- a further improvement for scenario 2, made robust by the presence of additional channels-
The content of the two channels of most any stereo recording differ.. to some extent. Yet are also the same.. to some other extent. In a concert taper recording, some of the particulars of how they are the same and differ will be specific to the recording setup used - specifically and in large degree a consequence of the stereo microphone arrangement. There will be signal relationships specific to: a stereo pair of mics of some particular pickup pattern, spaced a certain distance apart, angled a certain angle apart. Some of the relationships between the two channels will be present in all recordings made with that setup.. as long as that setup remains unchanged. Additionally, some additional aspects will be specific to each specific recording situation. Those relationships will remain constant between channels for that particular recording as long as the recording location doesn't change over the course of the recording, but will differ between various recordings even though the same recording setup was used. The point is that there is useful information about the stereo similarities and differences between channels which gets encoded into each recording and remains constant throughout the recording. Information that is specific to the recording arrangement, and additionally to that specific recording arrangement in each specific recording situation. We should be able to use that to our advantage.
How can we extract that information and use it to filter the replacement cross-faded content so that its no longer just a mono copy of an alternate good channel, but rather is imbued with whatever typical stereo difference information is typical to that particular recording setup.. and more specifically to that particular recording setup in that particular recording situation?
With a four channels (or more) rather than just two, the encoded information about the recording array and the specific situation in which it is used becomes far more robust. As channel count increases arithmetically, the cross-relationships between each chanel and channel groupings increases geometrically.
I dream of a program which analyzes a recording made with a static, unchanging multichannel microphone array, determines useful things about the cross-correlations between all channels, and uses that to synthesize a convincing missing channel from the channels that remain. Some day..
